Catalysts

24 pages, 4024 KB

Open AccessEditor’s ChoiceArticle

Synthesis of Novel Key Chromophoric Intermediates via C-C Coupling Reactions

by Laila M. Nhari, Elham N. Bifari, Aisha R. Al-Marhabi, Huda A. Al-Ghamdi, Sameera N. Al-Ghamdi, Fatimah A. M. Al-Zahrani, Khalid O. Al-Footy and Reda M. El-Shishtawy

Catalysts 2022, 12(10), 1292; https://doi.org/10.3390/catal12101292 - 21 Oct 2022

Cited by 6 | Viewed by 5425

Abstract

The fundamentals of Pd-catalyzed Csp²−Csp² Miyaura borylation, Suzuki cross-coupling, and Stille cross-coupling reactions for a variety of borylated precursors based on phenothiazine (PTZ), phenoxazine (POZ), carbazole (Cz), and quinoxaline (QX) units have been explored. Three palladium-based catalysts were chosen for [...] Read more.

The fundamentals of Pd-catalyzed Csp²−Csp² Miyaura borylation, Suzuki cross-coupling, and Stille cross-coupling reactions for a variety of borylated precursors based on phenothiazine (PTZ), phenoxazine (POZ), carbazole (Cz), and quinoxaline (QX) units have been explored. Three palladium-based catalysts were chosen for this study: Pd(PPh₃)₄, Pd(PPh₃)₂Cl₂, and Pd(dppf)Cl₂, applying different reaction conditions. Around 16 desired chromophores were successfully designed and synthesized using C-C cross-coupling reactions in moderate to excellent yields, including PTZ, POZ, and Cz units coupled with QX, indolinium iodide, thienyl, phenyl, or triphenylamine moieties. Additionally, PTZ, POZ, and Cz have been employed in synthesizing various pinacol boronate ester derivatives in good to moderate yields. Interestingly, Pd(dppf)Cl₂ was found to be the best catalyst for borylation, and C-C cross-coupling reactions occurred in as little as 30 min, with an excellent yield exceeding 98%. Pd(PPh₃)₄ and Pd(PPh₃)₂Cl₂ catalyzed the reaction to obtain the desired products in moderate to good yields after a long time (20–24 h). On the other hand, the Suzuki-Miyaura cross-coupling between N-(2-methyl)hexyl carbazole pinacol boronate ester derivative 10c and three halogenated quinoxaline derivatives—4-(3-(5-bromothiophen-2-yl)quinoxalin-2-yl)benzaldehyde (27), 4-(5-(3-(5-bromothiophen-2-yl)quinoxalin-2-yl)thiophen-2-yl)benzaldehyde (30), and 4-(3-chloroquinoxalin-2-yl)benzaldehyde (25) catalyzed by Pd(PPh₃)₄—afforded three carbazole-quinoxaline chromophores (28, 30, and 31, respectively) in 2–3 h, with good to excellent yields reaching 86%. The electron-deficient QX couplers proved to be coupled efficiently using the Stille coupling reaction, which involves the coupling between electron-rich orgaostannane and electron-deficient halide. The synthesized precursors and desired chromophores were characterized by FTIR, ¹H-NMR, ¹³C-NMR, and HRMS. Full article

(This article belongs to the Special Issue The Role of Catalysts in Functionalization of C-H and C-C Bonds)

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16 pages, 3824 KB

Open AccessArticle

Abundant Oxygen Vacancies Induced by the Mechanochemical Process Boost the Low-Temperature Catalytic Performance of MnO₂ in NH₃-SCR

by Yuanyuan Dong, Baofang Jin, Shaomian Liu, Jiajian Gao, Kangjun Wang and Fabing Su

Catalysts 2022, 12(10), 1291; https://doi.org/10.3390/catal12101291 - 21 Oct 2022

Cited by 10 | Viewed by 2801

Abstract

Manganese oxides (MnO_x) have attracted particular attention in the selective catalytic reduction of NO_x with NH₃ (NH₃-SCR) because of their excellent low-temperature activity. Herein, we prepared a highly efficient MnO₂ (MnO₂-M) catalyst through a [...] Read more.

Manganese oxides (MnO_x) have attracted particular attention in the selective catalytic reduction of NO_x with NH₃ (NH₃-SCR) because of their excellent low-temperature activity. Herein, we prepared a highly efficient MnO₂ (MnO₂-M) catalyst through a facile ball milling-assisted redox strategy. MnO₂-M shows a 90% NO_x conversion in a wide operating temperature window of 75–200 °C under a gas hourly space velocity of 40,000 h⁻¹, which is much more active than the MnO₂ catalyst prepared by the redox method without the ball-milling process. Moreover, MnO₂-M exhibits better H₂O and SO₂ resistance. The enhanced catalytic properties of MnO₂-M originated from the high surface area, abundant oxygen vacancies, more acid sites, and higher Mn⁴⁺ content induced by the ball-milling process. In situ DRIFTS studies probed the reaction intermediates, and the SCR reaction was deduced to proceed via the typical Eley–Rideal mechanism. This work provides a facile method to enhance the catalytic performance of Mn-based catalysts for low-temperature denitrification and deep insights into the NH₃-SCR reaction process. Full article

(This article belongs to the Special Issue Catalytic Treatment of Air Pollutants (VOCs, PACs, PCDDs/PCDFs, Soot, NOx, CO) II)

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11 pages, 3928 KB

Open AccessArticle

Photocatalytic Degradation of Eriochrome Black-T Using BaWO₄/MoS₂ Composite

by Yuvaraj M. Hunge, Anuja A. Yadav and Seok-Won Kang

Catalysts 2022, 12(10), 1290; https://doi.org/10.3390/catal12101290 - 21 Oct 2022

Cited by 50 | Viewed by 3599

Abstract

Photocatalytic degradation of organic compounds using semiconductor oxide materials has attracted increased attention in the recent decades. Both the catalysts and light play an important role in the photocatalytic degradation process. This research work focuses on the synthesis of BaWO₄/MoS₂ [...] Read more.

Photocatalytic degradation of organic compounds using semiconductor oxide materials has attracted increased attention in the recent decades. Both the catalysts and light play an important role in the photocatalytic degradation process. This research work focuses on the synthesis of BaWO₄/MoS₂ composite using green chemical method and its use in the degradation of Eriochrome black-T dye. Synthesized BaWO₄, and BaWO₄/MoS₂ composites were characterized by XRD, XPS, Raman, SEM, TEM, BET and UV-Vis characterizations techniques. BaWO₄/MoS₂ composite exhibits superior photocatalytic performance towards Eriochrome black-T degradation than BaWO₄. Superior photocatalytic activity of BaWO₄/MoS₂ composite corresponds to enhanced light absorption, effective charge generation, separation, and minimum recombination of photogenerated charge carriers. Full article

(This article belongs to the Special Issue UV/Vis/NIR Photocatalysis and Optical Properties)

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27 pages, 7657 KB

Open AccessReview

Asymmetric Hydroarylation Reactions Catalyzed by Transition Metals: Last 10 Years in a Mini Review

by Martina De Angelis, Antonia Iazzetti, Andrea Serraiocco and Alessia Ciogli

Catalysts 2022, 12(10), 1289; https://doi.org/10.3390/catal12101289 - 21 Oct 2022

Cited by 9 | Viewed by 3390

Abstract

Hydroarylation reactions play a pivotal role in organic chemistry due to their versatility and efficiency. In the last 10 years, the scientific production around this reaction has been very high, but in its asymmetric version, the results are less. In this mini review, [...] Read more.

Hydroarylation reactions play a pivotal role in organic chemistry due to their versatility and efficiency. In the last 10 years, the scientific production around this reaction has been very high, but in its asymmetric version, the results are less. In this mini review, selected literature examples are considered to draw attention to directions of the asymmetric hydroarylation reaction mediated by transition metal catalysts. The selected works were grouped in two main sections. In the first, we reported examples relating the narrower definition of hydroarylation, namely the metal-catalyzed processes where inactivated aryl moiety undergoes a direct functionalization via insertion of an unsaturated compound. In the second part, hydroarylation reactions take place with the use of pre-activated aryl substrates, usually aryl-iodides or aryl-boronated. Full article

(This article belongs to the Special Issue Advances in Transition Metal Catalysis)

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17 pages, 4703 KB

Open AccessFeature PaperArticle

3D-Printed Raney-Cu POCS as Promising New Catalysts for Methanol Synthesis

by Maximilian J. Poller, Christina Renz, Torsten Wolf, Carolin Körner, Peter Wasserscheid and Jakob Albert

Catalysts 2022, 12(10), 1288; https://doi.org/10.3390/catal12101288 - 21 Oct 2022

Cited by 3 | Viewed by 2558

Abstract

Simultaneous generation and activation of Raney-type periodic open cellular structures (POCS) is a highly promising approach for generating novel structured methanol synthesis catalysts. In detail, we produced stable and highly active POCS from a Cu50Al50 alloy by additive manufacturing via Powder Bed Fusion [...] Read more.

Simultaneous generation and activation of Raney-type periodic open cellular structures (POCS) is a highly promising approach for generating novel structured methanol synthesis catalysts. In detail, we produced stable and highly active POCS from a Cu50Al50 alloy by additive manufacturing via Powder Bed Fusion by Electron Beam (PBF-EB) and activated them via selective leaching of aluminum in a sodium hydroxide/sodium zincate solution. The Raney-type Cu structures possessed catalytic methanol productivities of up to 2.2 g_MeOHg_np-Cu h⁻¹ (PBF-EB sticks) and 1.9 g_MeOHg_np-Cu h⁻¹ (PBF-EB POCS), respectively. Moreover, it was found that besides the nanoporous layer thickness, an optimum Zn/Cu ratio of 0.3–0.4 can also by adjusted by the leaching conditions. Full article

(This article belongs to the Special Issue New Catalysts and Reactors for the Synthesis or Conversion of Methanol)

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16 pages, 6982 KB

Open AccessEditor’s ChoiceArticle

Computational Insights into Ru, Pd and Pt fcc Nano-Catalysts from Density Functional Theory Calculations: The Influence of Long-Range Dispersion Corrections

by Marietjie J. Ungerer and Nora H. De Leeuw

Catalysts 2022, 12(10), 1287; https://doi.org/10.3390/catal12101287 - 21 Oct 2022

Cited by 6 | Viewed by 4246

Abstract

Ruthenium, palladium and platinum fall within the group of noble metals that are widely used in catalysis, especially for the electrocatalytic production of hydrogen. The dominant phase of the bulk Ru metal is hexagonal close-packed (hcp), which has been studied extensively. [...] Read more.

Ruthenium, palladium and platinum fall within the group of noble metals that are widely used in catalysis, especially for the electrocatalytic production of hydrogen. The dominant phase of the bulk Ru metal is hexagonal close-packed (hcp), which has been studied extensively. However, significantly less attention has been paid to the face-centred cubic (fcc) phases, which have been observed in nanoparticles. In this study, we have carried out density functional theory calculations with long-range dispersion corrections [DFT-D2, DFT-D3 and DFT-D3-(BJ)] to investigate the lattice parameters, surface energies and work functions of the (001), (011) and (111) surfaces of Ru, Pd and Pt in the fcc phase. When investigating the surface properties of the three metals, we observed that the DFT-D2 method generally underestimated the lattice parameters by up to 2.2% for Pt and 2.8% for Ru. The surface energies followed the observed trend (111) < (001) < (011) for both Ru and Pd with all three methods, which is comparable to experimental data. For Pt the same trend was observed with DFT-D2 and DFT-D3(BJ), but it deviated to Pt (111) < Pt (011) < Pt (001) for the DFT-D3 method. DFT-D2 overestimated the surface energies for all three Miller Indexes by 82%, 73%, and 60%, when compared to experimental values. The best correlation for the surface energies was obtained with the DFT-D3 and DFT-D3(BJ) methods, both of which have deviate by less than 15% deviation for all surfaces with respect to experiment. The work function followed the trend of Φ (111) < Φ (001) < Φ (011) for all three metals and calculated by all three methods. Five different types of Ru, Pd and Pt nanoparticles were considered, including icosahedral, decahedral, cuboctahedral, cubic and spherical particles of different sizes. The bulk, surface and nanoparticle calculations showed that the DFT-D2 method for Pt overestimated the exchange-correlation, leading to higher energy values that can be contributed erroneously to a more stable structure. The calculations showed that as soon as the surface-to-bulk ratio > 1, the energy per atom resembles bulk energy values. Full article

(This article belongs to the Special Issue Application of Heterogeneous Catalysts in Energy Conversion and Storage Systems)

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17 pages, 3719 KB

Open AccessArticle

Spillover Hydrogen on Electron-Rich Ni/m-TiO₂ for Hydrogenation of Furfural to Tetrahydrofurfuryl Alcohol

by Ravi Balaga, Kishore Ramineni, Xiaoqiang Zhang, Peifang Yan, Mahender Reddy Marri, Vijayanand Perupogu and Zongchao Conrad Zhang

Catalysts 2022, 12(10), 1286; https://doi.org/10.3390/catal12101286 - 21 Oct 2022

Cited by 13 | Viewed by 3338

Abstract

Conversion of biomass-derived furfural (FFA) platform molecule to value-added tetrahydrofurfuryl alcohol (THFA) molecule is a sustainable route using an efficient non-noble metallic catalyst in water solvent. In this work, Ni in various loadings on mesoporous titanium dioxide (m-TiO₂) was synthesized in [...] Read more.

Conversion of biomass-derived furfural (FFA) platform molecule to value-added tetrahydrofurfuryl alcohol (THFA) molecule is a sustainable route using an efficient non-noble metallic catalyst in water solvent. In this work, Ni in various loadings on mesoporous titanium dioxide (m-TiO₂) was synthesized in one pot by Evaporation-Induced Self-Assembly (EISA). The synthesised catalysts were evaluated for the hydrogenation of furfural to tetrahydrofurfuryl alcohol. The catalysts were characterised using a combination of spectroscopic techniques such as XRD, H₂-TPR, H₂-TPD, XPS, SEM-EDX, TEM, and HR-TEM. The characterization results show that the Ni/m-TiO₂ materials exhibit enhanced electron-rich active sites, facilitated hydrogen spillover, uniform dispersion of small Ni particles (~5 nm), and strong metal support interaction between Ni and TiO₂. Among the various Ni dopings, 7.5 wt.% Ni/m-TiO₂ catalyst exhibited the best performance and achieved 99.9% FFA conversion and 93.2% THFA selectivity in water solvent at 100 °C and under 2 MPa H₂. Additionally, detailed kinetic studies, process parameters, the stability and reusability of the catalyst were also studied. The results demonstrated that the 7.5 wt.% Ni/m-TiO₂ catalyst is highly active and stable. Full article

(This article belongs to the Special Issue Advanced Catalysts for the Production of Fuels or Chemicals from Biomass)

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13 pages, 3369 KB

Open AccessArticle

Structure Sensitivity of Ammonia Synthesis on Cobalt: Effect of the Cobalt Particle Size on the Activity of Promoted Cobalt Catalysts Supported on Carbon

by Magdalena Zybert, Aleksandra Tarka, Wojciech Patkowski, Hubert Ronduda, Bogusław Mierzwa, Leszek Kępiński and Wioletta Raróg-Pilecka

Catalysts 2022, 12(10), 1285; https://doi.org/10.3390/catal12101285 - 21 Oct 2022

Cited by 10 | Viewed by 3191

Abstract

This work presents a size effect, i.e., catalyst surface activity, as a function of active phase particle size in a cobalt catalyst for ammonia synthesis. A series of cobalt catalysts supported on carbon and doped with barium was prepared, characterized (TEM, XRPD, and [...] Read more.

This work presents a size effect, i.e., catalyst surface activity, as a function of active phase particle size in a cobalt catalyst for ammonia synthesis. A series of cobalt catalysts supported on carbon and doped with barium was prepared, characterized (TEM, XRPD, and H₂ chemisorption), and tested in ammonia synthesis (9.0 MPa, 400 °C, H₂/N₂ = 3, 8.5 mol% of NH₃). The active phase particle size was varied from 3 to 45 nm by changing the metal loading in the range of 4.9–67.7 wt%. The dependence of the reaction rate expressed as TOF on the active phase particle size revealed an optimal size of cobalt particles (20–30 nm), ensuring the highest activity of the cobalt catalyst in the ammonia synthesis reaction. This indicated that the ammonia synthesis reaction on cobalt is a structure-sensitive reaction. The observed effect may be attributed to changes in the crystalline structure, i.e., the appearance of the hcp Co phase for the particles with a diameter of 20–30 nm. Full article

(This article belongs to the Special Issue Applied Catalysis in Chemical Industry: Synthesis, Catalyst Design, and Evaluation)

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17 pages, 1061 KB

Open AccessArticle

Production and Characterization of Durvillaea antarctica Enzyme Extract for Antioxidant and Anti-Metabolic Syndrome Effects

by Ming-Kuei Shih, Chih-Yao Hou, Cheng-Di Dong, Anil Kumar Patel, Yung-Hsiang Tsai, Mei-Chun Lin, Zheng-Ying Xu, Pitchurajan Krishna Perumal, Chia-Hung Kuo and Chun-Yung Huang

Catalysts 2022, 12(10), 1284; https://doi.org/10.3390/catal12101284 - 21 Oct 2022

Cited by 9 | Viewed by 2851

Abstract

In this study, three enzyme hydrolysate termed Dur-A, Dur-B, and Dur-C, were produced from Durvillaea antarctica biomass using viscozyme, cellulase, and α-amylase, respectively. Dur-A, Dur-B, and Dur-C, exhibited fucose-containing sulfated polysaccharide from chemical composition determination and characterization by FTIR analyses. In addition, Dur-A, [...] Read more.

In this study, three enzyme hydrolysate termed Dur-A, Dur-B, and Dur-C, were produced from Durvillaea antarctica biomass using viscozyme, cellulase, and α-amylase, respectively. Dur-A, Dur-B, and Dur-C, exhibited fucose-containing sulfated polysaccharide from chemical composition determination and characterization by FTIR analyses. In addition, Dur-A, Dur-B, and Dur-C, had high extraction yields and low molecular weights. All extracts determined to have antioxidant activities by DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS (2,20-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt), and ferrous ion-chelating methods. All extracts were also able to positively suppress the activities of key enzymes involved in metabolic syndrome: angiotensin I-converting enzyme (ACE), α-amylase, α-glucosidase, and pancreatic lipase. In general, Dur-B exhibited higher antioxidant and higher anti-metabolic syndrome effects as compared to the other two extracts. Based on the above health promoting properties, these extracts (especially Dur-B) can be used as potential natural antioxidants and natural anti-metabolic syndrome agents in a variety of food, cosmetic, and nutraceutical products for health applications. Full article

(This article belongs to the Special Issue Enzymes in Biomedical, Cosmetic and Food Application)

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21 pages, 505 KB

Open AccessArticle

Integral Characteristic of Complex Catalytic Reaction Accompanied by Deactivation

by Zoë Gromotka, Gregory Yablonsky, Nickolay Ostrovskii and Denis Constales

Catalysts 2022, 12(10), 1283; https://doi.org/10.3390/catal12101283 - 20 Oct 2022

Cited by 3 | Viewed by 2120

Abstract

New theoretical relationships for a complex catalytic reaction accompanied by deactivation are obtained, using as an example the two-step catalytic mechanism (Temkin–Boudart mechanism) with irreversible reactions and irreversible deactivation. In the domain of small concentrations, [...] Read more.

New theoretical relationships for a complex catalytic reaction accompanied by deactivation are obtained, using as an example the two-step catalytic mechanism (Temkin–Boudart mechanism) with irreversible reactions and irreversible deactivation. In the domain of small concentrations,

A_{\lim} = N_{S} \frac{k_{1} C_{A}}{k_{d}},

where

A_{\lim}

is the limit of the integral consumption of the gas substance,

N_{S}

is the number of active sites per unit of catalyst surface;

k_{1}

and

k_{d}

, are kinetic coefficients which relate to two reactions which compete for the free active site Z.

C_{A}

is the gas concentration. One reaction belongs to the catalytic cycle. The other reaction with kinetic coefficient

k_{d}

is irreversible deactivation. The catalyst lifetime,

τ_{cat} = \frac{1}{C_{Z}^{'}} \frac{1}{k_{d}}

, where

C_{Z}^{'}

is the dimensionless steady-state concentration of free active sites. The main conclusion was formulated as follows: the catalyst lifetime can be enhanced by decreasing the steady-state (quasi-steady-state) concentration of free active sites. In some domains of parameters, it can also be achieved by increasing the steady-state (quasi-steady-state) reaction rate of the fresh catalyst. We can express this conclusion as follows: under some conditions, an elevated fresh catalyst activity protects the catalyst from deactivation. These theoretical results are illustrated with the use of computer simulations. Full article

(This article belongs to the Section Catalytic Materials)

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13 pages, 3386 KB

Open AccessArticle

Electrophoretic Deposition of Graphene Oxide and Reduced Graphene Oxide on the Rutile Phase of TiO₂ Nanowires for Rapid Reduction of Cr (VI) under Simulated Sunlight Irradiation

by Subagja Toto Rahmat, Nurhaswani Alias, Rajesh Kumar, Wai Kian Tan, Go Kawamura, Atsunori Matsuda and Zainovia Lockman

Catalysts 2022, 12(10), 1282; https://doi.org/10.3390/catal12101282 - 20 Oct 2022

Cited by 13 | Viewed by 2699

Abstract

Hexavalent chromium is very carcinogenic, and it is, therefore, important to remove it from wastewater prior to disposal. This study reports the photoreduction of Cr(VI) under simulated sunlight using graphene-derived TiO₂ nanowire (TNW) composites. Electrophoretic deposition (EPD) of graphene oxide (GO) and [...] Read more.

Hexavalent chromium is very carcinogenic, and it is, therefore, important to remove it from wastewater prior to disposal. This study reports the photoreduction of Cr(VI) under simulated sunlight using graphene-derived TiO₂ nanowire (TNW) composites. Electrophoretic deposition (EPD) of graphene oxide (GO) and reduced graphene oxide (rGO) was carried out on rutile phase TNWs. The TNWs were fabricated by thermal oxidation of titanium foil in the presence of 1M potassium hydroxide mist at 750 °C. The TNWs uniformly covered the surface of the titanium foil. EPD of GO or rGO was done as a function of time to produce deposits of different thicknesses. The photocatalytic performances of the GO/TNWs or rGO/TNWs were tested to reduce Cr(VI) under visible light. The performance of rGO/TNWs in reducing Cr(VI) was better than GO/TNWs. A 10-second-deposited rGO on TNW samples can reduce 10 mg/L Cr(VI) within 30 min under visible light, likely as a result of the high electron transfer from rGO to TNWs accelerating the Cr(VI) reduction. Full article

(This article belongs to the Section Nanostructured Catalysts)

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14 pages, 5133 KB

Open AccessFeature PaperArticle

Self-Doped Carbon Dots Decorated TiO₂ Nanorods: A Novel Synthesis Route for Enhanced Photoelectrochemical Water Splitting

by Chau Thi Thanh Thuy, Gyuho Shin, Lee Jieun, Hyung Do Kim, Ganesh Koyyada and Jae Hong Kim

Catalysts 2022, 12(10), 1281; https://doi.org/10.3390/catal12101281 - 20 Oct 2022

Cited by 7 | Viewed by 2803

Abstract

Herein, we have successfully prepared self-doped carbon dots with nitrogen elements (NCD) in a simple one-pot hydrothermal carbonization method, using L-histidine as a new precursor. The effect of as-prepared carbon dots was studied for photoelectrochemical (PEC) water splitting by decorating NCDs upon TiO [...] Read more.

Herein, we have successfully prepared self-doped carbon dots with nitrogen elements (NCD) in a simple one-pot hydrothermal carbonization method, using L-histidine as a new precursor. The effect of as-prepared carbon dots was studied for photoelectrochemical (PEC) water splitting by decorating NCDs upon TiO₂ nanorods systematically by changing the loading time from 2 h to 8 h (TiO₂@NCD2h, TiO₂@NCD4h, TiO₂@NCD6h, and TiO₂@NCD8h). The successful decorating of NCDs on TiO₂ was confirmed by FE-TEM and Raman spectroscopy. The TiO₂@NCD4h has shown a photocurrent density of 2.51 mA.cm⁻², 3.4 times higher than the pristine TiO₂. Moreover, TiO₂@NCD4h exhibited 12% higher applied bias photon-to-current efficiency (ABPE) than the pristine TiO₂. The detailed IPCE, Mott–Schottky, and impedance (EIS) analyses have revealed the enhanced light harvesting property, free carrier concentration, charge separation, and transportation upon introduction of the NCDs on TiO₂. The obtained results clearly portray the key role of NCDs in improving the PEC performance, providing a new insight into the development of highly competent TiO₂ and NCDs based photoanodes for PEC water splitting. Full article

(This article belongs to the Special Issue Catalytic Methods for the Synthesis of Carbon Nanodots and Their Applications)

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14 pages, 3284 KB

Open AccessArticle

DFT Investigations on the Ring-Opening Polymerization of Trimethylene Carbonate Catalysed by Heterocyclic Nitrogen Bases

by Michael Lalanne-Tisné, Audrey Favrelle-Huret, Wim Thielemans, João P. Prates Ramalho and Philippe Zinck

Catalysts 2022, 12(10), 1280; https://doi.org/10.3390/catal12101280 - 20 Oct 2022

Cited by 5 | Viewed by 2754

Abstract

Organocatalysts for polymerization have known a huge interest over the last two decades. Among them, heterocyclic nitrogen bases are widely used to catalyse the ring-opening polymerization (ROP) of heterocycles such as cyclic carbonates. We have investigated the ring-opening polymerization of trimethylene carbonate (TMC) [...] Read more.

Organocatalysts for polymerization have known a huge interest over the last two decades. Among them, heterocyclic nitrogen bases are widely used to catalyse the ring-opening polymerization (ROP) of heterocycles such as cyclic carbonates. We have investigated the ring-opening polymerization of trimethylene carbonate (TMC) catalysed by DMAP (4-dimethylaminopyridine) and TBD (1,5,7-triazabicyclo[4.4.0]dec-5-ene) as case studies in the presence of methanol as co-initiator by Density Functional Theory (DFT). A dual mechanism based on H-bond activation of the carbonyl moieties of the monomer and a basic activation of the alcohol co-initiator has been shown to occur more preferentially than a direct nucleophilic attack of the carbonate monomer by the heterocyclic nitrogen catalyst. The rate-determining step of the mechanism is the ring opening of the TMC molecule, which is slightly higher than the nucleophilic attack of the TMC carbonyl by the activated alcohol. The calculations also indicate TBD as a more efficient catalyst than DMAP. The higher energy barrier found for DMAP vs. TBD, 23.7 vs. 11.3 kcal·mol⁻¹, is corroborated experimentally showing a higher reactivity for the latter. Full article

(This article belongs to the Special Issue Catalysts for the Ring Opening Polymerization)

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15 pages, 5681 KB

Open AccessArticle

Efficient Cross-Coupling of Acetone with Linear Aliphatic Alcohols over Supported Copper on a Fluorite-Type Pr₂Zr₂O₇

by Suhyun Lim, Minseok Kim, Sang Hyeok Ko, Jae-Hong Lee, Joon Hyun Baik and Young-Woong Suh

Catalysts 2022, 12(10), 1279; https://doi.org/10.3390/catal12101279 - 20 Oct 2022

Cited by 1 | Viewed by 2266

Abstract

In cross-coupling of biomass-derived acetone and alcohols contributing to the production of carbon-elongated chemicals and fuels, the essential catalyst components are metal dispersion for alcohol dehydrogenation and, more importantly, basicity for carbon–carbon coupling. Herein, we report the potential of co-precipitated praseodymia–zirconia solid solution [...] Read more.

In cross-coupling of biomass-derived acetone and alcohols contributing to the production of carbon-elongated chemicals and fuels, the essential catalyst components are metal dispersion for alcohol dehydrogenation and, more importantly, basicity for carbon–carbon coupling. Herein, we report the potential of co-precipitated praseodymia–zirconia solid solution (Pr₂Zr₂O₇) as a support of Cu catalyst for the conversion of acetone and butanol into C₇ and C₁₁ products. Cu/Pr₂Zr₂O₇ exhibits a high yield of C₇ and C₁₁ (ca. 84%) compared to Cu/ZrO₂ and Cu/PrO_1.83. Moreover, it is robust under the employed solvent-free conditions owing to a solid solution of Pr₂Zr₂O₇ compared to PrO_1.83 showing phase transition to PrOHCO₃. It is also tolerant to up to 5 wt % water of the reactant mixture, recyclable once adequate post-treatment is employed after the reaction, and can convert the acetone–butanol–ethanol mixture into C₅–C₁₁ products at the nearly equivalent yield (82%) to the acetone–butanol mixture. Therefore, the Cu/Pr₂Zr₂O₇ reported herein is an efficient catalyst for the coupling of acetone with linear aliphatic alcohols into biofuel precursors. Full article

(This article belongs to the Special Issue Catalysis for Environmentally Benign Production of Alternative Fuels)

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10 pages, 2270 KB

Open AccessArticle

Selective C-O Coupling Reaction of N-Methoxy Arylamides and Arylboronic Acids Catalyzed by Copper Salt

by Ying Wang, Huilin Xie, Kunming Liu, Jinhui Li and Jin-Biao Liu

Catalysts 2022, 12(10), 1278; https://doi.org/10.3390/catal12101278 - 19 Oct 2022

Cited by 6 | Viewed by 3104

Abstract

Herein, we report a copper-catalyzed C-O cross-coupling of N-methoxy amides and arylboronic acids for the synthesis of aryl-N-methoxy arylimides. The fully selective O-arylation of the N-methoxy amides is found to be greatly prompted by the inexpensive and commercially available CuI. The reaction conditions [...] Read more.

Herein, we report a copper-catalyzed C-O cross-coupling of N-methoxy amides and arylboronic acids for the synthesis of aryl-N-methoxy arylimides. The fully selective O-arylation of the N-methoxy amides is found to be greatly prompted by the inexpensive and commercially available CuI. The reaction conditions tolerate a variety of functional groups and promote different reactivities depending on the electronic and steric properties of the distorted substrates. Full article

(This article belongs to the Special Issue Catalyzed Carbon-Heteroatom Bond Formation)

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25 pages, 7840 KB

Open AccessArticle

Catalytic Oxidative Decomposition of Dimethyl Methyl Phosphonate over CuO/CeO₂ Catalysts Prepared Using a Secondary Alkaline Hydrothermal Method

by Weimin Kong, Shuyuan Zhou, Xuwei Wang, Qingrong He, Piaoping Yang, Ye Yuan and Yanchun Dong

Catalysts 2022, 12(10), 1277; https://doi.org/10.3390/catal12101277 - 19 Oct 2022

Cited by 4 | Viewed by 2777

Abstract

Bimetallic synergism plays an important role in lattice-doped catalysts. Therefore, lattice-doped bimetallic CuO/CeO₂ catalysts were prepared by secondary alkaline hydrothermal reaction. During this process, the CeO₂ nanomaterials were partially dissolved and recrystallized; thus, Cu ions were doped into the CeO₂ [...] Read more.

Bimetallic synergism plays an important role in lattice-doped catalysts. Therefore, lattice-doped bimetallic CuO/CeO₂ catalysts were prepared by secondary alkaline hydrothermal reaction. During this process, the CeO₂ nanomaterials were partially dissolved and recrystallized; thus, Cu ions were doped into the CeO₂ lattice. The physical and chemical properties of CeO₂, CuO/CeO₂, and CuO were investigated. H₂ temperature-programmed reduction characterization showed that the oxidation activity of CuO/CeO₂ was significantly improved. X-ray photoelectron spectroscopy results showed that electron transfer occurred between Ce and Cu in the CuO/CeO₂ catalyst. Additionally, Raman characterization confirmed the strong interaction between Cu and Ce. After CuO was loaded, the thermal catalytic decomposition performance of the catalyst was significantly improved with respect to the sarin simulant dimethyl methyl phosphonate (DMMP); with an increase in the Cu/Ce ratio, the performance first strengthened and then weakened. Additionally, the reaction tail gas and catalyst surface products were analyzed using mass spectrometry and ion chromatography, and the changes in the surface products during the thermal catalytic decomposition of DMMP were characterized at different temperatures using in situ diffuse reflectance infrared Fourier transform spectroscopy. Finally, the catalytic reaction pathways of DMMP on CeO₂, CuO/CeO₂, and CuO were inferred. The study results not only demonstrate an effective catalyst for the removal of nerve agent but also a feasible preparation method for lattice-doped bimetallic catalysts in the field of environmental protection. Full article

(This article belongs to the Special Issue Ceria-Based Heterogeneous Catalysis: Experimental and Theoretical Study)

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12 pages, 3998 KB

Open AccessArticle

Two-Dimensional Fe-N-C Nanosheets for Efficient Oxygen Reduction Reaction

by Xin Wu, Wenke Xie, Xuanhe Liu, Xiaoming Liu and Qinglan Zhao

Catalysts 2022, 12(10), 1276; https://doi.org/10.3390/catal12101276 - 19 Oct 2022

Cited by 6 | Viewed by 3042

Abstract

Fe-N-doped carbon (Fe-N-C)-based electrocatalysts are considered to be promising alternatives to replace Pt-based catalysts for oxygen reduction reactions (ORR). Here, we reported a simple and effective approach to prepare Fe-N-C-based electrocatalysts with the shape of two-dimensional nanosheets (termed Fe/NCNSs) to enhance the ORR [...] Read more.

Fe-N-doped carbon (Fe-N-C)-based electrocatalysts are considered to be promising alternatives to replace Pt-based catalysts for oxygen reduction reactions (ORR). Here, we reported a simple and effective approach to prepare Fe-N-C-based electrocatalysts with the shape of two-dimensional nanosheets (termed Fe/NCNSs) to enhance the ORR performance. Fe/NCNSs were prepared by the calcination of Fe/Zn dual-metal ZIFs nanosheets as precursors. Benefiting from its higher specific surface area, electrochemically active surface area, and proportion of pyridinic N and Fe-N, the optimized Fe/NCNS showed excellent ORR performance both in acidic (E_1/2 = 0.725 V vs. RHE) and alkaline (E_1/2 = 0.865 vs. RHE) media, being 23 mV more negative and 24 mV more positive than that of a commercial Pt/C. The optimized Fe/NCNS also exhibited long durability. In addition, the Zn-air battery with Fe/NCNS-1 and RuO₂ as the air catalyst exhibited high power density (1590 mW cm⁻² at a current density of 2250 mA cm⁻²) and superior charging/discharging durability. Full article

(This article belongs to the Special Issue Heterogeneous Electrocatalysis: Fundamentals and Applications II)

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16 pages, 2304 KB

Open AccessArticle

Thermodynamic and Kinetic Study of Carbon Dioxide Hydrogenation on the Metal-Terminated Tantalum-Carbide (111) Surface: A DFT Calculation

by Saeedeh Sarabadani Tafreshi, S. Fatemeh. K. S. Panahi, Narges Taghizade, Maryam Jamaati, Mahkameh Ranjbar and Nora H. de Leeuw

Catalysts 2022, 12(10), 1275; https://doi.org/10.3390/catal12101275 - 19 Oct 2022

Cited by 6 | Viewed by 2849

Abstract

The need to reduce our reliance on fossil fuels and lessen the environmentally harmful effects of CO₂ have encouraged investigations into CO₂ hydrogenation to produce useful products. Transition metal carbides exhibit a high propensity towards CO₂ activation, which makes them [...] Read more.

The need to reduce our reliance on fossil fuels and lessen the environmentally harmful effects of CO₂ have encouraged investigations into CO₂ hydrogenation to produce useful products. Transition metal carbides exhibit a high propensity towards CO₂ activation, which makes them promising candidates as suitable catalysts for CO₂ hydrogenation. Here, we have employed calculations based on the density-functional theory to investigate the reaction network for CO₂ hydrogenation to product molecules on the tantalum-terminated TaC (111) surface, including two routes from either HCOOH* or HOCOH* intermediates. Detailed calculations of the reaction energies and energy barriers along multiple potential catalytic pathways, along with the exploration of all intermediates, have shown that CH₄ is the predominant product yielded through a mechanism involving HCOOH, with a total exothermic reaction energy of −4.24 eV, and energy barriers between intermediates ranging from 0.126 eV to 2.224 eV. Other favorable products are CO and CH₃OH, which are also produced via the HCOOH pathway, with total overall reaction energies of −2.55 and −2.10 eV, respectively. Our calculated thermodynamic and kinetic mechanisms that have identified these three predominant products of the CO₂ hydrogenation catalyzed by the TaC (111) surface explain our experimental findings, in which methane, carbon monoxide, and methanol have been observed as the major reaction products. Full article

(This article belongs to the Special Issue Application of Heterogeneous Catalysts in Energy Conversion and Storage Systems)

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19 pages, 4415 KB

Open AccessArticle

Solvent-Free Synthesis of Nickel Nanoparticles as Catalysts for CO₂ Hydrogenation to Methane

by Olga V. Netskina, Kirill A. Dmitruk, Alexander A. Paletsky, Svetlana A. Mukha, Alena A. Pochtar, Olga A. Bulavchenko, Igor P. Prosvirin, Andrey G. Shmakov, Anna M. Ozerova, Janna V. Veselovskaya, Olga I. Mazina and Oxana V. Komova

Catalysts 2022, 12(10), 1274; https://doi.org/10.3390/catal12101274 - 19 Oct 2022

Cited by 7 | Viewed by 2985

Abstract

The solid-state combustion method was used to prepare nickel-based catalysts for CO₂ hydrogenation from [Ni(C₃H₄N₂)₆](NO₃)₂ and [Ni(C₃H₄N₂)₆](ClO₄)₂. These complexes [...] Read more.

The solid-state combustion method was used to prepare nickel-based catalysts for CO₂ hydrogenation from [Ni(C₃H₄N₂)₆](NO₃)₂ and [Ni(C₃H₄N₂)₆](ClO₄)₂. These complexes were synthesized by adding nickel nitrate and perchlorate to melted imidazole. The composition and structure of the obtained complexes was confirmed by ATR FTIR, powder XRD, and elemental analysis. The stages of thermal decomposition of the complexes and their kinetic parameters were established. It was found that incomplete gasification of more thermostable Ni(C₃H₄N₂)₆](ClO₄)₂ led to the formation of carbon, nitrogen, and chlorine impurities. According to powder XRD and XPS, the solid products of gasification of both complexes consist of NiO and Ni⁰ covered with nickel hydroxide and/or a carbonate layer. In the case of the sample prepared from [Ni(C₃H₄N₂)₆](ClO₄)₂, this layer was pronounced. Therefore, it limits the nickel reduction in the reaction medium of CO₂ hydrogenation, even at 450 °C. The surface of the sample prepared from [Ni(C₃H₄N₂)₆](NO₃)₂ contains nickel oxide, which is easily reduced. So, the catalyst active phase is already formed at 250 °C in the presence of CO₂ and efficiently catalyzes CO₂ hydrogenation as the temperature increases. Therefore, [Ni(C₃H₄N₂)₆](NO₃)₂ is a promising precursor for the CO₂ hydrogenation catalyst, and its solvent-free synthesis follows Green Chemistry principles. Full article

(This article belongs to the Special Issue Catalytic Purification of Pollutants and Catalytic Conversion of Solid Wastes)

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14 pages, 3779 KB

Open AccessArticle

Clean Syngas and Hydrogen Co-Production by Gasification and Chemical Looping Hydrogen Process Using MgO-Doped Fe₂O₃ as Redox Material

by Maria Paola Bracciale, Martina Damizia, Paolo De Filippis and Benedetta de Caprariis

Catalysts 2022, 12(10), 1273; https://doi.org/10.3390/catal12101273 - 19 Oct 2022

Cited by 8 | Viewed by 2932

Abstract

Gasification converts biomass into syngas; however, severe cleaning processes are necessary due to the presence of tars, particulates and contaminants. The aim of this work is to propose a cleaning method system based on tar physical adsorption coupled with the production of pure [...] Read more.

Gasification converts biomass into syngas; however, severe cleaning processes are necessary due to the presence of tars, particulates and contaminants. The aim of this work is to propose a cleaning method system based on tar physical adsorption coupled with the production of pure H₂ via a chemical looping process. Three fixed-bed reactors with a double-layer bed (NiO/Al₂O₃ and Fe-based particles) working in three different steps were used. First, NiO/Al₂O₃ is used to adsorb tar from syngas (300 °C); then, the adsorbed tar undergoes partial oxidization by NiO/Al₂O₃ to produce CO and H₂ used for iron oxide reduction. In the third step, the reduced iron is oxidized with steam to produce pure H₂ and to restore iron oxides. A double-layer fixed-bed reactor was fed alternatively by guaiacol and as tar model compounds, air and water were used. High-thermal-stability particles 60 wt% Fe₂O₃/40 wt% MgO synthetized by the coprecipitation method were used as Fe-based particles in six cycle tests. The adsorption efficiency of the NiO/Al₂O₃ bed is 98% and the gas phase formed is able to partially reduce iron, favoring the reduction kinetics. The efficiency of the process related to the H₂ production after the first cycle is 35% and the amount of CO is less than 10 ppm. Full article

(This article belongs to the Special Issue Catalysts for Sustainable Hydrogen Production: Preparation, Applications and Process Integration, 2nd Edition)

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32 pages, 24573 KB

Open AccessReview

3D Printing/Vat Photopolymerization of Photopolymers Activated by Novel Organic Dyes as Photoinitiators

by Ke Sun, Xiaotong Peng, Zengkang Gan, Wei Chen, Xiaolin Li, Tao Gong and Pu Xiao

Catalysts 2022, 12(10), 1272; https://doi.org/10.3390/catal12101272 - 19 Oct 2022

Cited by 15 | Viewed by 3508

Abstract

Even though numerous organic dyes which are used as photoinitiators/photocatalysts during photopolymerization have been systematically investigated and collected in previous reviews, further designs of these chromophores and the developments in high-performance photoinitiating systems have emerged in recent years, which play the crucial role [...] Read more.

Even though numerous organic dyes which are used as photoinitiators/photocatalysts during photopolymerization have been systematically investigated and collected in previous reviews, further designs of these chromophores and the developments in high-performance photoinitiating systems have emerged in recent years, which play the crucial role in 3D printing/Vat polymerization. Here, in this mini-review, various families of organic dyes that are used as newly synthesized photoinitiators/photocatalysts which were reported in literature during 2021–2022 are specified by their photoinitiation mechanisms, which dominate their performance during photopolymerization, especially in 3D printing. Markedly, visible light-induced polymerization could be employed in circumstances not only upon the irradiation of artificial light sources, e.g., in LEDs, but also in sunlight irradiation. Furthermore, a short overview of the achievements of newly developed mechanisms, e.g., RAFT, photoinitiator-RAFT, and aqueous RAFT using organic chromophores as light-harvesting compounds to induce photopolymerization upon visible light irradiation are also thoroughly discussed. Finally, the reports on the semiconducting nanomaterials that have been used as photoinitiators/photocatalysts during photopolymerization are also introduced as perspectives that are able to expand the scope of 3D printing and materials science due to their various advantages such as high extinction coefficients, broad absorption spectra, and having multiple molecular binding points. Full article

(This article belongs to the Section Photocatalysis)

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13 pages, 2740 KB

Open AccessArticle

Ex Situ Upgrading of Extra Heavy Oil: The Effect of Pore Shape of Co-Mo/γ-Al₂O₃ Catalysts

by Alexey Y. Kirgizov, Baodong Ding, Artur A. Spiridonov, Lei Liu, Artem I. Laskin, Chang Cao, Il’dar R. Il’yasov, Ameen A. Al-Muntaser, Xiaodong Zhou, Radik A. Zinnatov, Alexander A. Lamberov, Chengdong Yuan and Mikhail A. Varfolomeev

Catalysts 2022, 12(10), 1271; https://doi.org/10.3390/catal12101271 - 18 Oct 2022

Cited by 4 | Viewed by 2846

Abstract

Co-Mo/γ-Al₂O₃ catalysts with different pore shapes were synthesized for the ex situ upgrading of extra heavy oils by hydrodesulfurization (HDS), hydrodemetallization (HDM), and hydrodeasphaltization (HDA). The catalysts were synthesized using aluminum oxides that were prepared by various methods. It was [...] Read more.

Co-Mo/γ-Al₂O₃ catalysts with different pore shapes were synthesized for the ex situ upgrading of extra heavy oils by hydrodesulfurization (HDS), hydrodemetallization (HDM), and hydrodeasphaltization (HDA). The catalysts were synthesized using aluminum oxides that were prepared by various methods. It was found that using the product obtained by the thermochemical activation of gibbsite leads to the formation of slit-shaped pores in aluminum oxide, while the application of the hydroxide deposition method by the precipitation of sodium aluminate and nitric acid gives cylindrical pores in aluminum oxide. Co-Mo catalysts synthesized using these two types of pores exhibit different catalytic activities. The catalyst synthesized on a carrier with cylindrical pores exhibited a higher catalytic activity in sulfur, heavy metals, and asphaltenes removal reactions that are synthesized on a carrier with slit-like pores. This is because the presence of cylindrical pores leads to a decrease in diffusion restrictions when removing large molecules of asphaltenes and sulfur-containing and metal-containing compounds. Full article

(This article belongs to the Special Issue Heterogeneous Catalysis in Enhanced Oil Recovery: Prospects and Challenges)

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17 pages, 6486 KB

Open AccessArticle

Ni-Al Self-Propagating High-Temperature Synthesis Catalysts in Dry Reforming of Methane to Hydrogen-Enriched Fuel Mixtures

by Svetlana Tungatarova, Galina Xanthopoulou, George Vekinis, Konstantinos Karanasios, Tolkyn Baizhumanova, Manapkhan Zhumabek and Marzhan Sadenova

Catalysts 2022, 12(10), 1270; https://doi.org/10.3390/catal12101270 - 18 Oct 2022

Cited by 6 | Viewed by 2822

Abstract

The worldwide increase in demand for environmentally friendly energy has led to the intensification of work on the synthesis of H₂-containing fuel. The dry reforming of methane has become one of the most important avenues of research since the consumption of [...] Read more.

The worldwide increase in demand for environmentally friendly energy has led to the intensification of work on the synthesis of H₂-containing fuel. The dry reforming of methane has become one of the most important avenues of research since the consumption of two greenhouse gases reduces the rate of global warming. A study of NiAl composite materials as catalysts for methane reforming has been carried out. Self-propagating high-temperature synthesis (SHS) has been used to produce NiAl catalysts. Comparative studies were carried out regarding the dry reforming and partial oxidation of methane, as well as catalysts prepared using the impregnation (IM) and SHS methods. A catalyst with 29% Ni and 51% Al after SHS contains the phases of NiAl and NiAl₂O₄, which are active phases in the dry reforming of methane. The optimal crystal lattice parameter (for the maximum possible conversion of CO₂ and CH₄) is 3.48–3.485 Å for Al₂O₃, which plays the role of a catalyst carrier, and 1.42 Å, for NiAl₂O₄, which plays the role of a catalyst. The aim of the work is to develop a new and efficient catalyst for the dry reforming of methane into a synthesis gas, which will further promote the organization of a new era of environmentally friendly energy-saving production methods. Full article

(This article belongs to the Special Issue Catalytic Conversion of Low Carbon Alkane)

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14 pages, 3799 KB

Open AccessArticle

Solar Light-Induced Photocatalytic Degradation of Ciprofloxacin Antibiotic Using Biochar Supported Nano Bismuth Ferrite Composite

by Nur Azra Aqilah Mohd Azan, Suresh Sagadevan, Abdul Rahman Mohamed, Amirul Hazwan Nor Azazi, Faiz Bukhari Mohd Suah, Takaomi Kobayashi, Rohana Adnan and Noor Haida Mohd Kaus

Catalysts 2022, 12(10), 1269; https://doi.org/10.3390/catal12101269 - 18 Oct 2022

Cited by 23 | Viewed by 3230

Abstract

Research on advanced materials for environmental remediation and pollutant degradation is rapidly progressing because of their numerous applications. Biochar is an excellent material support for the catalytic activity of bismuth ferrite (BiFeO₃), which is one of the best perovskite-based photocatalysts in [...] Read more.

Research on advanced materials for environmental remediation and pollutant degradation is rapidly progressing because of their numerous applications. Biochar is an excellent material support for the catalytic activity of bismuth ferrite (BiFeO₃), which is one of the best perovskite-based photocatalysts in this work for diverse pollutant degradation when exposed to direct sunlight. Biochar was produced by pyrolyzing oil palm empty fruit bunches (OPEFBs) and then integrate with BiFeO₃ in the presence of cross-linked chitosan to create a BFO/biochar coupled magnetic photocatalyst (CBB). This research was conducted to examine the performance of the photocatalytic activity of CBB towards the degradation of ciprofloxacin antibiotics. To determine the optimal condition, two operational parameters that are photocatalyst dosage and initial pollutant concentrations, were evaluated. The results of the powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscope-energy dispersive X-ray (SEM-EDX) analyses confirmed the high purity of the rhombohedral BiFeO₃ with a high surface area, as well as the successful coupling of BiFeO₃ and biochar at a ratio of 1:1. The most effective conditions for the various variables are 1.5 g/L CBB dosage at 10 ppm with 77.08% photodegradation under direct sunlight for 2 h. Further, a pseudo-first-order kinetic reaction was followed and observed with decreasing k values as the initial concentration increased. This shows that the system performs best at low concentrations. This finding confirms that the catalytic parameters improved the efficiency of photocatalysts with biochar assistance in removing antibiotic pollutants. Full article

(This article belongs to the Special Issue Advances on Green Synthesis of Nanocomposites and Environmental Applications in Adsorption and Catalytic Degradation of Pollutants)

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26 pages, 6370 KB

Open AccessArticle

Study of the Hydrothermal-Catalytic Influence on the Oil-Bearing Rocks of the Usinskoye Oil Field

by Irek I. Mukhamatdinov, Artem V. Lapin, Rezeda E. Mukhamatdinova, Aydar A. Akhmadiyarov, Boudkhil Affane, Dmitriy A. Emel’yanov, Olga V. Slavkina and Alexey V. Vakhin

Catalysts 2022, 12(10), 1268; https://doi.org/10.3390/catal12101268 - 18 Oct 2022

Cited by 9 | Viewed by 2131

Abstract

In this work, a synthesis of an oil-soluble iron-based catalyst precursor was carried out and its efficiency was tested in a laboratory simulation of the aquathermolysis process at different temperatures. The rocks of the Usinskoe field from the Permian deposits of the Komi [...] Read more.

In this work, a synthesis of an oil-soluble iron-based catalyst precursor was carried out and its efficiency was tested in a laboratory simulation of the aquathermolysis process at different temperatures. The rocks of the Usinskoe field from the Permian deposits of the Komi Republic, obtained by steam-gravity drainage, and the iron-based catalyst precursor, as well as the products of non-catalytic and catalytic aquathermolysis, were selected as the object of study. As a result, it was found that the content of alkanes in the samples after thermal steam treatment (TST) at 300 °C increased 8-fold compared to the original oil, and the content of cycloalkanes in the sample with the catalyst increased 2-fold compared to the control experience. This may indicate that not only the carbon-heteroatom bonds (C-S, N, O) but also the C-C bonds were broken. It also shows that increasing the iron tallate concentration at TST 300 °C leads to a decrease in the molecular mass of the oil compared to the control experiment. According to SEM, the catalyst is nanodisperse particles with a size of ≈60–80 nm, which are adsorbed on the rock surface, catalyst removal occurs at a small scale. Full article

(This article belongs to the Special Issue Catalysis for Bitumen/Heavy Oil Upgrading and Petroleum Refining)

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14 pages, 2439 KB

Open AccessArticle

Surface Modification of GdMn₂O₅ for Catalytic Oxidation of Benzene via a Mild A-Site Sacrificial Strategy

by Ju Gao, Xu Dong, Zhenguo Li, Yuankai Shao, Xiaoning Ren, Kaixiang Li and Yiren Lu

Catalysts 2022, 12(10), 1267; https://doi.org/10.3390/catal12101267 - 18 Oct 2022

Cited by 5 | Viewed by 2020

Abstract

Thermal catalytic oxidation technology is an effective way to eliminate refractory volatile organic pollutants, such as Benzene. Nevertheless, a high reaction temperature is usually an obstacle to practical application. Here, GdMn₂O₅ mullite (GMO-H) catalyst with disordered surface Gd-deficient and oxygen-vacancy-rich [...] Read more.

Thermal catalytic oxidation technology is an effective way to eliminate refractory volatile organic pollutants, such as Benzene. Nevertheless, a high reaction temperature is usually an obstacle to practical application. Here, GdMn₂O₅ mullite (GMO-H) catalyst with disordered surface Gd-deficient and oxygen-vacancy-rich concentrations was synthesized via a controllable low-temperature acid-etching route. Results show that the preferentially broken Gd-O bond is conducive to exposing more Mn-Mn active sites, which Gd species covered. The affluent surface oxygen vacancies supply sufficient adsorption sites for oxygen molecules, facilitating the oxygen cycles during Benzene catalytic oxidation. Furthermore, surface exposed Mn³⁺ species were oxidized to Mn⁴⁺, which is beneficial to increase catalytic activity at a lower temperature. Compared with the conventional GdMn₂O₅, the reaction temperature for removing 90% Benzene over GMO-H was dropped from 405 to 310 °C with WHSV of 30,000 mL g⁻¹ h⁻¹. Significantly, during a 72 h catalytic test, the catalytic activity remains constant at 90% of the Benzene removal at 300 °C, indicating excellent activity stability. This work reported an efficient approach to preparing manganese-base mullite thermal catalyst, providing insight into the catalytic oxidation of Benzene. Full article

(This article belongs to the Section Environmental Catalysis)

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14 pages, 5048 KB

Open AccessArticle

Environmentally Safe Magnetic Nanocatalyst for the Production of Biodiesel from Pongamia pinnata Oil

by Hafiza Qurat ul Ain Sami, Muhammad Asif Hanif, Umer Rashid, Shafaq Nisar, Ijaz Ahmad Bhatti, Samuel Lalthazuala Rokhum, Toshiki Tsubota and Ali Alsalme

Catalysts 2022, 12(10), 1266; https://doi.org/10.3390/catal12101266 - 18 Oct 2022

Cited by 9 | Viewed by 2911

Abstract

Biodiesel is an alternative fuel in many developing and developed countries worldwide. Biodiesel has significant and numerous economic, environmental, and social benefits. However, the problem with conventional biodiesel production is the high industrial production cost, mainly contributed by the raw materials. Therefore, catalysts [...] Read more.

Biodiesel is an alternative fuel in many developing and developed countries worldwide. Biodiesel has significant and numerous economic, environmental, and social benefits. However, the problem with conventional biodiesel production is the high industrial production cost, mainly contributed by the raw materials. Therefore, catalysts and feedstock are essential in increasing total biodiesel production rates and minimizing production costs. Magnetic nano-catalysts play a crucial role in heterogeneous catalysis due to their easy recovery, recyclability, excellent selectivity, and fast reaction rates, owing to their larger surface area. This research activity used heterogeneous magnetic nano-catalysts of ICdO, ISnO, and their modified form, to produce biodiesel. The synthesized nano-catalysts were made through co-precipitation and found quite efficient for transesterifying Pongamia pinnata oil. The effect of various parameters on biodiesel yield in the presence of prepared magnetic nano-catalysts has been studied. In the transesterification supported by ISnO, high yield, i.e., 99%, was achieved after 2 h of reaction time at 60 °C. The nano-catalysts were magnetically recovered and reused 4–5 times without any change in their activity. All the synthesized magnetic nano-catalysts performed SEM analysis. Each fraction of the produced biodiesel was assessed for different quality parameters, and the results were per ASTM standards. The components present in biodiesel produced from Pongamia pinnata oil were determined by GCMS. Full article

(This article belongs to the Section Biomass Catalysis)

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15 pages, 11138 KB

Open AccessCommunication

Highly Efficient Synthesis of Cinnamamides from Methyl Cinnamates and Phenylethylamines Catalyzed by Lipozyme^® TL IM under Continuous-Flow Microreactors

by Lihua Du, Lingyan Zheng, Yue Pan, Zhikai Sheng, Shiyi Zhang, Hang Lin, Aoying Zhang, Hanjia Xie and Xiping Luo

Catalysts 2022, 12(10), 1265; https://doi.org/10.3390/catal12101265 - 18 Oct 2022

Cited by 7 | Viewed by 4362

Abstract

While a few derivatives of cinnamamides exhibited anti-inflammatory and/ or analgesic activity, in this study, we developed a highly efficient method for the synthesis of cinnamamides from methyl cinnamates and phenylethylamines catalyzed by Lipozyme^® TL IM in continuous-flow microreactors. The reaction parameters [...] Read more.

While a few derivatives of cinnamamides exhibited anti-inflammatory and/ or analgesic activity, in this study, we developed a highly efficient method for the synthesis of cinnamamides from methyl cinnamates and phenylethylamines catalyzed by Lipozyme^® TL IM in continuous-flow microreactors. The reaction parameters and broad substrate range of the new method was studied. Maximum conversion (91.3%) was obtained under the optimal condition of substrate molar ratio of 1:2 (methyl 4-chlorocinnamate: phenylethylamine) at 45

° C

for about 40 min. The remarkable features of this work include short residence time, mild reaction conditions, easy control of the reaction process, and that the catalyst can be recycled or reused, which provide a rapid and economical strategy for the synthesis and design of cinnamamide derivatives for further research on drug activity. Full article

(This article belongs to the Topic Bioreactors: Control, Optimization and Applications)

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10 pages, 3506 KB

Open AccessArticle

In Situ X-ray Absorption Spectroscopy Cells for High Pressure Homogeneous Catalysis

by Petr V. Shvets, Pavel A. Prokopovich, Artur I. Dolgoborodov, Oleg A. Usoltsev, Alina A. Skorynina, Elizaveta G. Kozyr, Viktor V. Shapovalov, Alexander A. Guda, Aram L. Bugaev, Evgeny R. Naranov, Dmitry N. Gorbunov, Kwinten Janssens, Dirk E. De Vos, Alexander L. Trigub, Emiliano Fonda, Mark B. Leshchinsky, Vladimir R. Zagackij, Alexander V. Soldatov and Alexander Yu. Goikhman

Catalysts 2022, 12(10), 1264; https://doi.org/10.3390/catal12101264 - 17 Oct 2022

Cited by 8 | Viewed by 3306

Abstract

We have designed, built, and tested two cells for in situ and, potentially, operando X-ray absorption spectroscopy experiments in transmission and fluorescence modes. The cells were developed for high-pressure and high-temperature conditions to study the catalytic processes under relevant industrial conditions. Operation of [...] Read more.

We have designed, built, and tested two cells for in situ and, potentially, operando X-ray absorption spectroscopy experiments in transmission and fluorescence modes. The cells were developed for high-pressure and high-temperature conditions to study the catalytic processes under relevant industrial conditions. Operation of the cells was tested for Ru and Rh-based homogeneous and heterogeneous catalytic systems. Using synchrotron-based in situ X-ray absorption spectroscopy we tracked the evolution of active metal species during catalytic reactions. Our setup proved that it was capable to investigate liquid-state homogeneous and heterogenous systems under elevated temperatures, high pressures of reactive gasses, and in the presence of corrosive reagents. Full article

(This article belongs to the Topic Catalysis: Homogeneous and Heterogeneous)

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39 pages, 8915 KB

Open AccessFeature PaperReview

Preparation and Photocatalytic Activities of TiO₂-Based Composite Catalysts

by Huaitao Yang, Beibei Yang, Wei Chen and Junjiao Yang

Catalysts 2022, 12(10), 1263; https://doi.org/10.3390/catal12101263 - 17 Oct 2022

Cited by 106 | Viewed by 15519

Abstract

While modern industry has contributed to the prosperity of an increasingly urbanized society, it has also led to serious pollution problems, with discharged wastewater and exhaust gases causing significant environmental harm. Titanium dioxide (TiO₂), which is an excellent photocatalyst, has received [...] Read more.

While modern industry has contributed to the prosperity of an increasingly urbanized society, it has also led to serious pollution problems, with discharged wastewater and exhaust gases causing significant environmental harm. Titanium dioxide (TiO₂), which is an excellent photocatalyst, has received extensive attention because it is inexpensive and able to photocatalytically degrade pollutants in an environmentally friendly manner. TiO₂ has many advantages, including high chemical stability, low toxicity, low operating costs, and environmental friendliness. TiO₂ is an N-order semiconductor material with a bandgap of 3.2 eV. Only when the wavelength of ultraviolet light is less than or equal to 387.5 nm, the valence band electrons can obtain the energy of the photon and pass through the conduction band to form photoelectrons, meanwhile the valence band forms a photogenerated hole. And light in other wavelength regions does not excite this photogenerated electrons. The most common methods used to improve the photocatalytic efficiency of TiO₂ involve increasing its photoresponse range and reducing photogenerated-carrier coupling. The morphology, size, and structure of a heterojunction can be altered through element doping, leading to improved photocatalytic efficiency. Mainstream methods for preparing TiO₂ are reviewed in this paper, with several excellent preparation schemes for improving the photocatalytic efficiency of TiO₂ introduced. TiO₂ is mainly prepared using sol-gel, solvothermal, hydrothermal, anodic oxidation, microwave-assisted, CVD and PVD methods, and TiO₂ nanoparticles with excellent photocatalytic properties can also be prepared. Ti-containing materials are widely used to purify harmful gases, as well as contaminants from building materials, coatings, and daily necessities. Therefore, the preparation and applications of titanium materials have become globally popular research topics. Full article

(This article belongs to the Special Issue Preparation and Photocatalytic Activity of TiO₂-Based Composite Catalysts)

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