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Volume 14
Issue 7
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Catalysts, Volume 14, Issue 7 (July 2024) – 75 articles

Cover Story (view full-size image): ERI and SSZ-13 were subjected to post-synthetic treatments (depending on the zeolite topology) to create micro/mesoporous materials. The post-synthetic modification of the investigated zeolites varied their catalytic activity in the selective catalytic reduction of NO with ammonia (NH3-SCR-DeNOx). Regarding the Cu-containing ERI, the NO conversion was higher for catalysts with modified supports. For the Cu-containing SSZ-13 catalysts (with post-modified zeolites), a lower NO conversion in NH3-SCR-DeNOx was observed. According to the physico-chemical characterization, the modification of the supports resulted in the presence of different amounts and kinds of copper species (especially isolated Cu2+ and aggregated Cu species) of ERI- and SSZ-13-based samples. View this paper
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17 pages, 2834 KiB  
Communication
A First-Principles Study on the Reaction Mechanisms of Electrochemical CO2 Reduction to C1 and C2 Products on Cu(110)
by Yangyang Xu and Lixin Zhang
Catalysts 2024, 14(7), 468; https://doi.org/10.3390/catal14070468 - 22 Jul 2024
Viewed by 678
Abstract
The mechanism of the electrochemical CO2 reduction reaction on a Cu(110) surface has yet to be fully revealed. In this work, based on first-principles calculations, we investigate the mechanisms of the CO2 reduction reaction to produce C1 (including one C [...] Read more.
The mechanism of the electrochemical CO2 reduction reaction on a Cu(110) surface has yet to be fully revealed. In this work, based on first-principles calculations, we investigate the mechanisms of the CO2 reduction reaction to produce C1 (including one C atom) and C2 (including two C atoms) products on a Cu(110) surface. The results show that CH4 and C2H5OH are the main C1 and C2 products on the Cu(110) surface, respectively. CH4 is produced along the pathway CO2 → COOH* → CO* → CHO* → CH2O* → CH3O* → CH4. C2H5OH is produced via the C-C coupling pathway between CO* and CH2O* intermediates, which is the key reaction step. This is because CO* and CH2O* coupling to CO-CH2O* has the lowest barrier among the CHxO* (x = 0–2) coupling pathways. Therefore, it is the most likely C-C coupling pathway. Further, CO-CH2O* is gradually hydrogenated to C2H5OH along the following pathway: CO-CH2O* → CHO-CH2O* → CHOH-CH2* → CH2OH-CH2* → CH2OH-CH3* → C2H5OH. Full article
(This article belongs to the Section Electrocatalysis)
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9 pages, 820 KiB  
Article
Synthesis of Propiolic and Butynedioic Acids via Carboxylation of CaC2 by CO2 under Mild Conditions
by Xiao-Min Zhao, Xiaoteng Zang, Yingzhou Lu, Hong Meng and Chunxi Li
Catalysts 2024, 14(7), 467; https://doi.org/10.3390/catal14070467 - 22 Jul 2024
Viewed by 735
Abstract
Carbon dioxide (CO2) is a greenhouse gas, and its resource use is vital for carbon reduction and neutrality. Herein, the nucleophilic addition reaction of calcium carbide (CaC2) to CO2 was studied for the first time to synthesize propiolic [...] Read more.
Carbon dioxide (CO2) is a greenhouse gas, and its resource use is vital for carbon reduction and neutrality. Herein, the nucleophilic addition reaction of calcium carbide (CaC2) to CO2 was studied for the first time to synthesize propiolic and butynedioic acids by using CuI or AgNO3 as catalyst, Na2CO3 as additive, and triphenylphosphine as ligand in the presence/absence of a hydrogen donor. The effects of the experimental conditions and intensification approach on the reaction were investigated. The reactivity of CaC2 is closely associated with its synergistic activation by the catalysts, solvent, and external intensification, such as the ultrasound and mechanical force. Ultrasound helps to promote the reaction by enhancing the interfacial mass transfer of CaC2 particulates. Mechanochemistry can effectively promote the reaction, yielding 29.8% of butynedioic acid and 74.8% of propiolic acid after 2 h ball milling at 150 rpm, arising from the effective micronization and interfacial renewal of calcium carbide. The present study sheds a light on the high-value uses of CO2 and CaC2 and is of reference significance for the nucleophilic reaction of CaC2 with other carbonyl compounds. Full article
(This article belongs to the Special Issue Feature Papers in "Industrial Catalysis" Section)
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14 pages, 1950 KiB  
Article
One-Pot Phyto-Mediated Synthesis of Fe2O3/Fe3O4 Binary Mixed Nanocomposite Efficiently Applied in Wastewater Remediation by Photo-Fenton Reaction
by Amr A. Essawy, Tamer H. A. Hasanin, Modather. F. Hussein, Emam F. El Agammy and Abd El-Naby I. Essawy
Catalysts 2024, 14(7), 466; https://doi.org/10.3390/catal14070466 - 20 Jul 2024
Cited by 1 | Viewed by 905
Abstract
A binary Fe2O3/Fe3O4 mixed nanocomposite was prepared by phyto-mediated avenue to be suited in the photo-Fenton photodegradation of methylene blue (MB) in the presence of H2O2. XRD and SEM analyses illustrated that [...] Read more.
A binary Fe2O3/Fe3O4 mixed nanocomposite was prepared by phyto-mediated avenue to be suited in the photo-Fenton photodegradation of methylene blue (MB) in the presence of H2O2. XRD and SEM analyses illustrated that Fe2O3 nanoparticles of average crystallite size 8.43 nm were successfully mixed with plate-like aggregates of Fe3O4 with a 15.1 nm average crystallite size. Moreover, SEM images showed a porous morphology for the binary Fe2O3/Fe3O4 mixed nanocomposite that is favorable for a photocatalyst. EDX and elemental mapping showed intense iron and oxygen peaks, confirming composite purity and symmetrical distribution. FTIR analysis displayed the distinct Fe-O assignments. Moreover, the isotherm of the developed nanocomposite showed slit-shaped pores in loose particulates within plate-like aggregates and a mesoporous pore-size distribution. Thermal gravimetric analysis (TGA) indicated the high thermal stability of the prepared Fe2O3/Fe3O4 binary nanocomposite. The optical properties illustrated a narrowing in the band gab (Eg = 2.92 eV) that enabled considerable absorption in the visible region of solar light. Suiting the developed binary Fe2O3/Fe3O4 nanocomposite in the photo-Fenton reaction along with H2O2 supplied higher productivity of active oxidizing species and accordingly a higher degradation efficacy of MB. The solar-driven photodegradation reactions were conducted and the estimated rate constants were 0.002, 0.0047, and 0.0143 min−1 when using the Fe2O3/Fe3O4 nanocomposite, pure H2O2, and the Fe2O3/Fe3O4/H2O2 hybrid catalyst, respectively. Therefore, suiting the developed binary Fe2O3/Fe3O4 nanocomposite and H2O2 in photo-Fenton reaction supplied higher productivity of active oxidizing species and accordingly a higher degradation efficacy of MB. After being subjected to four photo-Fenton degradation cycles, the Fe2O3/Fe3O4 nanocomposite catalyst still functioned admirably. Further evaluation of Fe2O3/Fe3O4 nanocomposite in photocatalytic remediation of contaminated water using a mixture of MB and pyronine Y (PY) dyestuffs revealed substantial dye photodegradation efficiencies. Full article
(This article belongs to the Special Issue Novel Nanocatalysts for Sustainable and Green Chemistry)
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16 pages, 3291 KiB  
Article
Effect of Support Functionalization on Catalytic Direct Hydrogenation and Catalytic Transfer Hydrogenation of Muconic Acid to Adipic Acid
by Elisa Zanella, Stefano Franchi, Narmin Jabbarli, Ilaria Barlocco, Marta Stucchi and Carlo Pirola
Catalysts 2024, 14(7), 465; https://doi.org/10.3390/catal14070465 - 19 Jul 2024
Viewed by 609
Abstract
The liquid-phase hydrogenation of muconic acid (MA) to produce bio-adipic acid (AdA) is a prominent environmentally friendly chemical process, that can be achieved through two distinct methodologies: catalytic direct hydrogenation using molecular hydrogen (H2), or catalytic transfer hydrogenation utilizing a hydrogen [...] Read more.
The liquid-phase hydrogenation of muconic acid (MA) to produce bio-adipic acid (AdA) is a prominent environmentally friendly chemical process, that can be achieved through two distinct methodologies: catalytic direct hydrogenation using molecular hydrogen (H2), or catalytic transfer hydrogenation utilizing a hydrogen donor. In this study, both approaches were explored, with formic acid (FA) selected as the hydrogen source for the latter method. Palladium-based catalysts were chosen for these processes. Metal’s nanoparticles (NPs) were supported on high-temperature heat-treated carbon nanofibers (HHT-CNFs) due to their known ability to enhance the stability of this metal catalyst. To assess the impact of support functionalization on catalyst stability, the HHT-CNFs were further functionalized with phosphorus and oxygen to obtain HHT-P and HHT-O, respectively. In the hydrogenation reaction, catalysts supported on functionalized supports exhibited higher catalytic activity and stability compared to Pd/HHT, reaching an AdA yield of about 80% in less than 2 h in batch reactor. The hydrogen-transfer process also yielded promising results, particularly with the 1%Pd/HHT-P catalyst. This work highlights the efficacy of support functionalization in improving catalyst performance, particularly when formic acid is used as a safer and more cost-effective hydrogen donor in the hydrogen-transfer process. Full article
(This article belongs to the Section Catalytic Materials)
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15 pages, 5759 KiB  
Article
Facile Preparation of Attapulgite-Supported Ag-AgCl Composite Photocatalysts for Enhanced Degradation of Tetracycline
by Xiaojie Zhang, Huiqin Wang and Chenlong Yan
Catalysts 2024, 14(7), 464; https://doi.org/10.3390/catal14070464 - 19 Jul 2024
Viewed by 572
Abstract
In this study, Ag-AgCl/attapulgite (Ag-AgCl/ATP) composites were synthesized via a direct precipitation method using ATP nanorods as a catalyst supporter. ATP nanorods helped to increase the dispersion of Ag-AgCl particles and broaden the light absorption spectrum, which would also help to increase the [...] Read more.
In this study, Ag-AgCl/attapulgite (Ag-AgCl/ATP) composites were synthesized via a direct precipitation method using ATP nanorods as a catalyst supporter. ATP nanorods helped to increase the dispersion of Ag-AgCl particles and broaden the light absorption spectrum, which would also help to increase the active site of the catalyst to promote the degradation of tetracycline (TC). The photocatalytic activity of the Ag-AgCl/ATP composites was evaluated through the degradation of TC, identifying the loading amount of Ag-AgCl, the concentration of TC, and the reaction temperature as critical factors influencing activity. Specifically, the optimal conditions were observed when the loading of Ag-AgCl was 75%, resulting in a photocatalytic degradation efficiency of 77.65%. Furthermore, the highest degradation efficiency (85.01%) was achieved with a TC concentration of 20 mg/L at 20 °C. Radical trapping experiments suggested that the superoxide anion radical (·O2−) was the primary active species in the degradation process, although hydroxyl radicals (·OH) and holes (h+) also contributed. Reusability tests confirmed that the Ag-AgCl/ATP composites exhibited excellent stability and could be effectively reused. Full article
(This article belongs to the Special Issue Mineral-Based Composite Catalytic Materials)
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15 pages, 2536 KiB  
Article
α-Alkylation of Aliphatic Ketones with Alcohols: Base Type as an Influential Descriptor
by Rasika Mane, Li Hui, Ander Centeno-Pedrazo, Alexandre Goguet, Nancy Artioli and Haresh Manyar
Catalysts 2024, 14(7), 463; https://doi.org/10.3390/catal14070463 - 19 Jul 2024
Viewed by 591
Abstract
Current global challenges associated with energy security and climate emergency, caused by the combustion of fossil fuels (e.g., jet fuel and diesel), necessitate the accelerated development and deployment of sustainable fuels derived from renewable biomass-based chemical feedstocks. This study focuses on the production [...] Read more.
Current global challenges associated with energy security and climate emergency, caused by the combustion of fossil fuels (e.g., jet fuel and diesel), necessitate the accelerated development and deployment of sustainable fuels derived from renewable biomass-based chemical feedstocks. This study focuses on the production of long-chain (straight and branched) ketones by direct α-alkylation of short chain ketones using both homogenous and solid base catalysts in water. Thus, produced long-chain ketones are fuel precursors and can subsequently be hydrogenated to long-chain alkanes suitable for blending in aviation and liquid transportation fuels. Herein, we report a thorough investigation of the catalytic activity of Pd in combination with, (i) homogenous and solid base additives; (ii) screening of different supports using NaOH as a base additive, and (iii) a comparative study of the Ni and Pd metals supported on layered double oxides (LDOs) in α-alkylation of 2-butanone with 1-propanol as an exemplar process. Among these systems, 5%Pd/BaSO4 with NaOH as a base showed the best results, giving 94% 2-butanone conversion and 84% selectivity to alkylated ketones. These results demonstrated that both metal and base sites are necessary for the selective conversion of 2-butanone to alkylated ketones. Additionally, amongst the solid base additives, Pd/C with 5% Ba/hydrotalcite showed the best result with 51% 2-butanone conversion and 36% selectivity to the alkylated ketones. Further, the screening of heterogenous acid-base catalysts 2.5%Ni/Ba1.2Mg3Al1 exhibited an adequate catalytic activity (21%) and ketone selectivity (47%). Full article
(This article belongs to the Section Catalysis for Sustainable Energy)
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17 pages, 3891 KiB  
Review
Mn-Based Catalysts in the Selective Reduction of NOx with CO: Current Status, Existing Challenges, and Future Perspectives
by Dianxing Lian, Mohaoyang Chen, Huanli Wang, Chenxi Li, Botao Liu, Guiyao Dai, Shujun Hou, Yuxi Liu and Yongjun Ji
Catalysts 2024, 14(7), 462; https://doi.org/10.3390/catal14070462 - 18 Jul 2024
Viewed by 888
Abstract
The technology for the selective catalytic reduction of NOx by CO (CO-SCR) has the capability to simultaneously eliminate CO and NOx from industrial flue gas and automobile exhaust, thus making it a promising denitrification method. The advancement of cost-effective and high-performing [...] Read more.
The technology for the selective catalytic reduction of NOx by CO (CO-SCR) has the capability to simultaneously eliminate CO and NOx from industrial flue gas and automobile exhaust, thus making it a promising denitrification method. The advancement of cost-effective and high-performing catalysts is crucial for the commercialization of this technology. Mn-based catalysts demonstrate enhanced catalytic efficiency under conditions of low temperature and low oxygen content when compared to other transition metal-based catalysts, indicating significant potential for practical applications. This review outlines the diverse Mn-based catalysts, including bulk or supported MnOx catalysts, bulk or supported Mn-based composite oxide catalysts, and the use of MnOx as dopants. Subsequently, the synthesis methods and catalytic mechanism employed by Mn-based catalysts are presented. The following section examines the impact of O2, H2O, and SO2 on the catalytic performance. Finally, the potential and implications of this reaction are deliberated. This work aims to offer theoretical guidance for the rational design of highly efficient Mn-based catalysts in the CO-SCR reaction for industrial applications. Full article
(This article belongs to the Special Issue Catalytic Energy Conversion and Catalytic Environmental Purification)
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7 pages, 1089 KiB  
Article
Methanol to Aromatics on Hybrid Structure Zeolite Catalysts
by Maria V. Magomedova, Ekaterina G. Galanova, Anastasia V. Starozhitskaya, Mikhail I. Afokin, David V. Matevosyan, Sergey V. Egazaryants, Dmitry E. Tsaplin and Anton L. Maximov
Catalysts 2024, 14(7), 461; https://doi.org/10.3390/catal14070461 - 18 Jul 2024
Viewed by 856
Abstract
A study on the reaction of methanol to aromatic hydrocarbons using catalysts based on hybrid zeolites MFI-MEL, MFI-MTW, and MFI-MCM-41 at a temperature of 340 °C and a pressure of 10.0 MPa was carried out. It is shown that in the synthesis of [...] Read more.
A study on the reaction of methanol to aromatic hydrocarbons using catalysts based on hybrid zeolites MFI-MEL, MFI-MTW, and MFI-MCM-41 at a temperature of 340 °C and a pressure of 10.0 MPa was carried out. It is shown that in the synthesis of hydrocarbons under pressure, the activity of the studied samples is similar and does not have a linear correlation with their total acidity. It was found that the catalyst’s activity is primarily determined by the rate of the initial methanol conversion reaction, which is related to the volume of micropores—more micropores lead to higher activity. Additionally, increasing the volume of mesopores results in the formation of heavier aromatic compounds, specifically C10–C11. Full article
(This article belongs to the Special Issue Microporous and Mesoporous Materials for Catalytic Applications)
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4 pages, 156 KiB  
Editorial
Catalysis on Zeolites and Zeolite-like Materials II
by Wladimir Reschetilowski
Catalysts 2024, 14(7), 460; https://doi.org/10.3390/catal14070460 - 17 Jul 2024
Viewed by 568
Abstract
This Special Issue is a continuation of the previous successful Special Issue, “Catalysis on Zeolites and Zeolite-Like Materials”, which presented the latest developments and advances in the synthesis, characterization, and application of zeolites and zeolite-like materials as catalysts by renowned scientists [...] Full article
(This article belongs to the Special Issue Catalysis on Zeolites and Zeolite-Like Materials II)
3 pages, 163 KiB  
Editorial
State of the Art in Molecular Catalysis in Europe
by Carl Redshaw
Catalysts 2024, 14(7), 459; https://doi.org/10.3390/catal14070459 - 16 Jul 2024
Viewed by 566
Abstract
In this editorial, I would like to provide an overview of the eleven contributions to the Special Issue entitled “State of the Art in Molecular Catalysis in Europe”, which is part of the Organic and Polymer Chemistry Section of Catalysts [...] Full article
(This article belongs to the Special Issue State of the Art in Molecular Catalysis in Europe)
19 pages, 1804 KiB  
Review
The Hydrogen Spillover Effect—A Misunderstanding Study II: Single Oxide and Zeolite Supports
by Mohammed M. Bettahar
Catalysts 2024, 14(7), 458; https://doi.org/10.3390/catal14070458 - 16 Jul 2024
Viewed by 793
Abstract
This investigation confirms that the existence of the hydrogen spillover effect (HSPE) in the case of metal catalysts supported on non-reducible monoxides or zeolites is based on a strong corpus of experimental studies, enlarging and deepening previous statements. The structure of hydrogen spillover [...] Read more.
This investigation confirms that the existence of the hydrogen spillover effect (HSPE) in the case of metal catalysts supported on non-reducible monoxides or zeolites is based on a strong corpus of experimental studies, enlarging and deepening previous statements. The structure of hydrogen spillover consists of H/OH pairs conjugated with Mm+/Op− pairs (p = 1 or 2). It is formed by dehydroxylation followed by OH/OH exchange or by the hydrogenation of conjugated pairs. Such a structure imposes the following chemical processes: (i) hydrogenations take place over OH Brönsted acid sites (BAS); (ii) they are excluded over Mm+/Op− Lewis acid sites (LASs), which are deactivating or dehydrogenating; (iii) surface diffusion of hydrogen spillover proceeds through the migration of H/H pairs from LASs to LASs; (iv) the diffusion rates are determined by the oxide supports’ basicity; and (v) H/D exchange is proof of the existence of hydrogen spillover. The nature of hydrogen spillover (radical/ionic) depends on the polarity of the H/OH pairs, which in turn, is determined by the basicity of the support. Our concept of conjugated active sites is a good descriptor of the reaction paths at the molecular level. The view of LASs bringing about additional activity to BAS is not pertinent. Full article
(This article belongs to the Special Issue Feature Papers in "Industrial Catalysis" Section)
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19 pages, 4209 KiB  
Article
Post-Synthetically Treated ERI and SSZ-13 Zeolites Modified with Copper as Catalysts for NH3-SCR-DeNOx
by Alejandro Mollá Robles, Gabriele Deplano, Kinga Góra-Marek, Marek Rotko, Anna Wach, Muhammad Fernadi Lukman, Marko Bertmer, Matteo Signorile, Silvia Bordiga, Andreas Pöppl, Roger Gläser and Magdalena Jabłońska
Catalysts 2024, 14(7), 457; https://doi.org/10.3390/catal14070457 - 16 Jul 2024
Cited by 1 | Viewed by 949
Abstract
ERI and SSZ-13 were subjected to post-synthetic treatments (depending on the zeolite topology) to create micro-/mesoporous materials. The results in terms of NH3-SCR-DeNOx show that the applied treatments improved the catalytic activity of the Cu-containing ERI-based materials; however, the NO [...] Read more.
ERI and SSZ-13 were subjected to post-synthetic treatments (depending on the zeolite topology) to create micro-/mesoporous materials. The results in terms of NH3-SCR-DeNOx show that the applied treatments improved the catalytic activity of the Cu-containing ERI-based materials; however, the NO conversion did not vary for the different materials treated with NaOH or NaOH/HNO3. For the micro-/mesoporous Cu-containing SSZ-13, a lower NO conversion in NH3-SCR-DeNOx was observed. Thus, our findings challenge the current paradigm of enhanced activity of micro-/mesoporous catalysts in NH3-SCR-DeNOx. The modification of the supports results in the presence of different amounts and kinds of copper species (especially isolated Cu2+ and aggregated Cu species) in the case of ERI- and SSZ-13-based samples. The present copper species further differentiate the formation of reactive reaction intermediates. Our studies show that besides the μ-η2,η2-peroxo dicopper(II) complexes (verified by in situ DR UV-Vis spectroscopy), copper nitrates (evidenced by in situ FT-IR spectroscopy) also act as reactive intermediates in these catalytic systems. Full article
(This article belongs to the Section Catalytic Materials)
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13 pages, 3466 KiB  
Article
Supported Inverse MnOx/Pt Catalysts Facilitate Reverse Water Gas Shift Reaction
by Wenli Bi, Ruoyu Zhang, Qingfeng Ge and Xinli Zhu
Catalysts 2024, 14(7), 456; https://doi.org/10.3390/catal14070456 - 16 Jul 2024
Viewed by 755
Abstract
Catalytic conversion of CO2 to CO via the reverse water gas shift (RWGS) reaction has been identified as a promising approach for CO2 utilization and mitigation of CO2 emissions. Bare Pt shows low activity for the RWGS reaction due to [...] Read more.
Catalytic conversion of CO2 to CO via the reverse water gas shift (RWGS) reaction has been identified as a promising approach for CO2 utilization and mitigation of CO2 emissions. Bare Pt shows low activity for the RWGS reaction due to its low oxophilicity, with few research works having concentrated on the inverse metal oxide/Pt catalyst for the RWGS reaction. In this work, MnOx was deposited on the Pt surface over a SiO2 support to prepare the MnOx/Pt inverse catalyst via a co-impregnation method. Addition of 0.5 wt% Mn to 1 wt% Pt/SiO2 improved the intrinsic reaction rate and turnover frequency at 400 °C by two and twelve times, respectively. Characterizations indicate that MnOx partially encapsulates the surface of the Pt particles and the coverage increases with increasing Mn content, which resembles the concept of strong metal–support interaction (SMSI). Although the surface accessible Pt sites are reduced, new MnOx/Pt interfacial perimeter sites are created, which provide both hydrogenation and C-O activation functionalities synergistically due to the close proximity between Pt and MnOx at the interface, and therefore improve the activity. Moreover, the stability is also significantly improved due to the coverage of Pt by MnOx. This work demonstrates a simple method to tune the oxide/metal interfacial sites of inverse Pt-based catalyst for the RWGS reaction. Full article
(This article belongs to the Special Issue Catalysis on Stable Molecules (CO2, CO, CH4, N2, NH3) Activation and Their Transformation, 2nd Edition)
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17 pages, 3156 KiB  
Article
Benefit of LDH-Derived Mixed Oxides for the Co-Oxidation of Toluene and CO Exhausted from Biomass Combustion
by Caroline Paris, Hadi Dib, Charf Eddine Bounoukta, Eric Genty, Christophe Poupin, Stéphane Siffert and Renaud Cousin
Catalysts 2024, 14(7), 455; https://doi.org/10.3390/catal14070455 - 16 Jul 2024
Viewed by 639
Abstract
The proposed study is devoted to highlighting the importance of mixed oxides preparation through the layered double hydroxide route for undesirable gas pollutants abatement. Different series of Cu/Al/Ce mixed oxides with similar or different stoichiometrics were prepared and compared for toluene and/or CO [...] Read more.
The proposed study is devoted to highlighting the importance of mixed oxides preparation through the layered double hydroxide route for undesirable gas pollutants abatement. Different series of Cu/Al/Ce mixed oxides with similar or different stoichiometrics were prepared and compared for toluene and/or CO oxidation. Catalyst synthesis methods influence material properties and activity for oxidation reactions. The high activity for the oxidation reactions of mixed oxides derived from LDH is explained by the Cu/Ce synergy. The presence of CO in the CO/toluene mixture does not affect the total toluene oxidation, and the toluene does not affect the total oxidation of CO conversion at low temperatures. The most effective catalytic material (Cu6Al1.2Ce0.8) presents a long lifetime stability for total toluene oxidation and resistance to CO poisoning in mixtures. Full article
(This article belongs to the Special Issue Layered Double Hydroxide-Based Catalysts for Advanced Chemical Technologies)
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16 pages, 4463 KiB  
Article
Electrocatalytic Hydrogen Evolution Reaction of Cobalt Triaryl Corrole Bearing Nitro Group
by Jie Zeng, Xu-You Cao, Shi-Yin Xu, Yi-Feng Qiu, Jun-Ying Chen, Li-Ping Si and Hai-Yang Liu
Catalysts 2024, 14(7), 454; https://doi.org/10.3390/catal14070454 - 15 Jul 2024
Cited by 1 | Viewed by 926
Abstract
The use of non–precious metals for electrocatalytic hydrogen reaction (HER) is particularly important for energy conservation and environmental protection. In this work, three new cobalt corroles containing o−, m−, and p−nitrobenzyl (1, 2, 3) at the [...] Read more.
The use of non–precious metals for electrocatalytic hydrogen reaction (HER) is particularly important for energy conservation and environmental protection. In this work, three new cobalt corroles containing o−, m−, and p−nitrobenzyl (1, 2, 3) at the meso 10−position of the corrole macrocycle were synthesized, and their electrocatalytic hydrogen evolution reaction in organic and neutral aqueous systems was also investigated. The results show that these three cobalt corroles have significant catalytic HER activity in both systems, and the catalytic efficiency follows 1 > 3 > 2, which indicates that the position of the nitro group can affect the catalytic property of the complexes. In the organic phase, when using trifluoroacetic acid or p−toluenesulfonic acid as the proton source, the electrocatalytic HER may undergo an EECC (E: electron transfer, C: proton coupling) pathway. In a neutral aqueous system, the HER turnover frequency value of 1 is up to 137.4 h−1 at 938 mV overpotential. Full article
(This article belongs to the Section Electrocatalysis)
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17 pages, 4066 KiB  
Article
Strong Magnetic p-n Heterojunction Fe3O4-FeWO4 for Photo-Fenton Degradation of Tetracycline Hydrochloride
by Binger Bai, Guanrong Cheng, Jian Chen, Xiaoping Chen and Qizhao Wang
Catalysts 2024, 14(7), 453; https://doi.org/10.3390/catal14070453 - 14 Jul 2024
Viewed by 743
Abstract
With the abuse of antibiotics, its pollution poses an increasing threat to the environment and human health. Effective degradation of organic pollutants in water bodies is urgent. Compared to traditional treatment methods, advanced oxidation processes that have developed rapidly in recent years are [...] Read more.
With the abuse of antibiotics, its pollution poses an increasing threat to the environment and human health. Effective degradation of organic pollutants in water bodies is urgent. Compared to traditional treatment methods, advanced oxidation processes that have developed rapidly in recent years are more environmentally friendly, efficient and applicable to a wider range of organic compounds. FeWO4 was used in this study as the iron-based semiconductor material to modify and optimize the material design. Fe3O4/FeWO4 composites were prepared by a two-step hydrothermal method. The crystal structure, surface morphology, electrochemical properties and separability of the composite semiconductor were analyzed by XRD, XPS, UV-vis, SEM, EDS and Mott-Schottky. The results showed that, when the initial contaminant concentration was 30 mg/L, the initial solution pH was 4, the dosage of the catalyst was 25 mg and the dosage of hydrogen peroxide was 30 μL, the degradation efficiency of tetracycline hydrochloride (TCH) could reach 91% within 60 min, which was significantly improved compared to the performance of the single semiconductors Fe3O4 and FeWO4. In addition, the catalyst prepared in this experiment can be easily recovered by magnetic separation technology in practical application, which will not affect the turbidity of water while reducing the cost of catalyst separation and recovery. Full article
(This article belongs to the Special Issue Two-Dimensional Materials in Photo(electro)catalysis)
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27 pages, 4004 KiB  
Review
Catalytic Applications in the Production of Hydrotreated Vegetable Oil (HVO) as a Renewable Fuel: A Review
by Nur-Sultan Mussa, Kainaubek Toshtay and Mickael Capron
Catalysts 2024, 14(7), 452; https://doi.org/10.3390/catal14070452 - 14 Jul 2024
Cited by 1 | Viewed by 1134
Abstract
The significance and challenges of hydrotreatment processes for vegetable oils have recently become apparent, encompassing various reactions like decarbonylation, decarboxylation, and hydrogenation. Heterogeneous noble or transition metal catalysts play a crucial role in these reactions, offering high selectivity in removing oxygen and yielding [...] Read more.
The significance and challenges of hydrotreatment processes for vegetable oils have recently become apparent, encompassing various reactions like decarbonylation, decarboxylation, and hydrogenation. Heterogeneous noble or transition metal catalysts play a crucial role in these reactions, offering high selectivity in removing oxygen and yielding desired hydrocarbons. Notably, both sulphided and non-sulphided catalysts exhibit effectiveness, with the latter gaining attention due to health and toxicity concerns associated with sulphiding agents. Nickel-based catalysts, such as NiP and NiC, demonstrate specific properties and tendencies in deoxygenation reactions, while palladium supported on activated carbon catalysts shows superior activity in hydrodeoxygenation. Comparisons between the performances of different catalysts in various hydrotreatment processes underscore the need for tailored approaches. Transition metal phosphides (TMP) emerge as promising catalysts due to their cost-effectiveness and environmental friendliness. Ultimately, there is an ongoing pursuit of efficient catalysts and the importance of further advancements in catalysis for the future of vegetable oil hydrotreatment. Full article
(This article belongs to the Section Biomass Catalysis)
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20 pages, 2772 KiB  
Review
Enhancing Trace Pb2⁺ Detection via Novel Functional Materials for Improved Electrocatalytic Redox Processes on Electrochemical Sensors: A Short Review
by Duowen Yang, Xinyu Wang and Hao Xu
Catalysts 2024, 14(7), 451; https://doi.org/10.3390/catal14070451 - 14 Jul 2024
Viewed by 1104
Abstract
The efficient detection of lead ions (Pb2⁺) is significant for environmental protection and public health. Electrochemical detection has emerged as one of the most promising technologies due to its low detection limits, high sensitivity, and cost-effectiveness. However, significant challenges remain, including [...] Read more.
The efficient detection of lead ions (Pb2⁺) is significant for environmental protection and public health. Electrochemical detection has emerged as one of the most promising technologies due to its low detection limits, high sensitivity, and cost-effectiveness. However, significant challenges remain, including issues related to sensitivity, selectivity, interference, and the stability of electrode materials. This review explores recent advancements in the field, focusing on integrating novel catalytic materials and innovative sensor construction methods. Particular emphasis is placed on enhancing the electrocatalytic redox processes on sensor surfaces using advanced nanomaterials such as MXenes, ferrite-based nanomaterials, carbon nanomaterials, and metal–organic frameworks (MOFs). Additionally, the role of biomaterials and enzymes in improving electrochemical sensors’ selectivity and anti-interference capabilities is discussed. Despite the impressive low detection limits achieved, real-world applications present additional challenges due to the complex composition of environmental samples. The review concludes with future perspectives on overcoming these challenges by leveraging the unique properties of catalytic materials to develop more effective and reliable electrochemical sensors for trace Pb2⁺ detection. Full article
(This article belongs to the Special Issue Electrocatalytic Wastewater Treatment: Resource Utilization and New Technology)
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48 pages, 11437 KiB  
Review
Advancing Plastic Recycling: A Review on the Synthesis and Applications of Hierarchical Zeolites in Waste Plastic Hydrocracking
by Muhammad Usman Azam, Waheed Afzal and Inês Graça
Catalysts 2024, 14(7), 450; https://doi.org/10.3390/catal14070450 - 12 Jul 2024
Cited by 1 | Viewed by 1170
Abstract
The extensive use of plastics has led to a significant environmental threat due to the generation of waste plastic, which has shown significant challenges during recycling. The catalytic hydrocracking route, however, is viewed as a key strategy to manage this fossil-fuel-derived waste into [...] Read more.
The extensive use of plastics has led to a significant environmental threat due to the generation of waste plastic, which has shown significant challenges during recycling. The catalytic hydrocracking route, however, is viewed as a key strategy to manage this fossil-fuel-derived waste into plastic-derived fuels with lower carbon emissions. Despite numerous efforts to identify an effective bi-functional catalyst, especially metal-loaded zeolites, the high-performing zeolite for hydrocracking plastics has yet to be synthesized. This is due to the microporous nature of zeolite, which results in the diffusional limitations of bulkier polymer molecules entering the structure and reducing the overall cracking of plastic and catalyst cycle time. These constraints can be overcome by developing hierarchical zeolites that feature shorter diffusion paths and larger pore sizes, facilitating the movement of bulky polymer molecules. However, if the hierarchical modification process of zeolites is not controlled, it can lead to the synthesis of hierarchical zeolites with compromised functionality or structural integrity, resulting in reduced conversion for the hydrocracking of plastics. Therefore, we provide an overview of various methods for synthesizing hierarchical zeolites, emphasizing significant advancements over the past two decades in developing innovative strategies to introduce additional pore systems. However, the objective of this review is to study the various synthesis approaches based on their effectiveness while developing a clear link between the optimized preparation methods and the structure-activity relationship of the resulting hierarchical zeolites used for the hydrocracking of plastics. Full article
(This article belongs to the Special Issue Heterogeneous Catalysis for Sustainable Conversion of Biomass, Carbon Dioxide and Plastic Waste into Fuels and Chemicals)
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23 pages, 8965 KiB  
Article
Novel Starch-Modified NiCrMn-LDH-Based Composite for Photocatalytic Degradation of Reactive Orange 13
by Muhammad Usman, Muhammad Babar Taj, Afaf Almasoudi, Doaa F. Baamer, Omar Makram Ali, Muhammad Imran Khan, Ismat Bibi, Mobeen Ur Rehman, Rabia Rasheed, Ahmad Raheel, Mushtaq Hussain Lashari, Abdallah Shanableh and Javier Fernandez-Garcia
Catalysts 2024, 14(7), 449; https://doi.org/10.3390/catal14070449 - 12 Jul 2024
Cited by 1 | Viewed by 719
Abstract
Water pollution has become a great challenge today. To address this problem regarding wastewater treatment by removing toxic synthetic dyes from wastewater, this research focused on the synthesis of a novel starch-modified NiCrMn-layered double hydroxide composite through the coprecipitation method and applied it [...] Read more.
Water pollution has become a great challenge today. To address this problem regarding wastewater treatment by removing toxic synthetic dyes from wastewater, this research focused on the synthesis of a novel starch-modified NiCrMn-layered double hydroxide composite through the coprecipitation method and applied it as a photocatalyst for the degradation of reactive orange 13 dye. The synthesized photocatalyst was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), point of zero charges (PZC), dynamic light scattering (DLS), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Zeta potential techniques. These techniques revealed different characteristics of photocatalysts, like surface and structural properties. According to BET analysis, the final composite had 2.5 × 102 m2/g BET-specific surface area with a 45.56 nm pore radius value, and the overall composite found as mesoporous. Similarly, in DLS analysis, bare NiCrMn-LDH had 404 nm hydrodynamic size, which increased for the final starch composite up to 667 nm. Zeta potential value changed from −14.56 mV to 0.95 mV after the incorporation of starch with NiCrMn-LDH. They confirmed the incorporation of starch with trimetallic NiCrMn-layered double hydroxide (2:1:2). Starch association improved the properties of the photocatalyst like surface area. Different parameters like pH value, initial dye concentration, photocatalyst dose, hydrogen peroxide concentration, effect of sacrificial reagent, and effect of inorganic anions were studied for degradation of RO13. Overall, the photocatalysis process for RO13 followed pseudo-first-order kinetics. Photocatalytic degradation reactions for reactive orange 13 were conducted with an initial dye concentration of 10 mg/L, photocatalyst dosage of 20 mg/50 mL, and pH value at 3 in the presence of sunlight, resulting in an impressive degradation removal rate of 86.68%. This remarkable degradation ability of the photocatalyst for reactive orange 13 proves this composite was highly efficient. Full article
(This article belongs to the Section Photocatalysis)
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19 pages, 2393 KiB  
Article
The Influence of Au Loading and TiO2 Support on the Catalytic Wet Air Oxidation of Glyphosate over TiO2+Au Catalysts
by Gregor Žerjav, Alen Albreht and Albin Pintar
Catalysts 2024, 14(7), 448; https://doi.org/10.3390/catal14070448 - 12 Jul 2024
Cited by 1 | Viewed by 651
Abstract
This study aimed to explore the impact of varying amounts of added Au (0.5 to 2 wt.%) and the structural characteristics of anatase TiO2 supports (nanoparticles (TP, SBET = 88 m2/g) and nanorods (TR, SBET = 105 m [...] Read more.
This study aimed to explore the impact of varying amounts of added Au (0.5 to 2 wt.%) and the structural characteristics of anatase TiO2 supports (nanoparticles (TP, SBET = 88 m2/g) and nanorods (TR, SBET = 105 m2/g)) on the catalytic efficiency of TiO2+Au catalysts in eliminating the herbicide glyphosate from aqueous solutions via the catalytic wet air oxidation (CWAO) process. The investigation was conducted using a continuous-flow trickle-bed reactor. Regardless of the TiO2 support and the amount of Au added, the addition of Au has a positive effect on the glyphosate degradation rate. Regarding the amount of Au added, the highest catalytic activity was observed with the TP + 1% Au catalyst, which had a higher Schottky barrier (SB) than the TP + 2% Au catalyst, which helped the charge carriers in the TiO2 conduction band to increase their reduction potential by preventing them from returning to the Au. The role of glyphosate degradation product adsorption on the catalyst surface is crucial for sustaining the long-term catalytic activity of the investigated TiO2+Au materials. This was particularly evident in the case of the TR + 1% Au catalyst, which had the highest glyphosate degradation rate at the beginning of the CWAO experiment, but its catalytic activity then decreased over time due to the adsorption of glyphosate degradation products, which was favoured by the presence of strong acidic sites. In addition, the TR + 1% Au solid had the smallest average Au particle size of all analyzed materials, which were more easily deactivated by the adsorption of glyphosate degradation products. The analysis of the degradation products of glyphosate shows that the oxidation of glyphosate in the liquid phase involves the rupture of C–P and C–N bonds, as amino-methyl-phosphonic acid (AMPA), glyoxylic acid and sarcosine were detected. Full article
(This article belongs to the Special Issue Environmental Catalysis in Advanced Oxidation Processes, 2nd Edition)
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36 pages, 3154 KiB  
Review
Photocatalytic Application of Polymers in Removing Pharmaceuticals from Water: A Comprehensive Review
by Sanja J. Armaković, Stevan Armaković and Maria M. Savanović
Catalysts 2024, 14(7), 447; https://doi.org/10.3390/catal14070447 - 12 Jul 2024
Cited by 1 | Viewed by 1202
Abstract
This comprehensive review covers recent advancements in utilizing various types of polymers and their modifications as photocatalysts for the removal of pharmaceutical contaminants from water. It also considers polymers that enhance the photocatalytic properties of other materials, highlighting their dual role in improving [...] Read more.
This comprehensive review covers recent advancements in utilizing various types of polymers and their modifications as photocatalysts for the removal of pharmaceutical contaminants from water. It also considers polymers that enhance the photocatalytic properties of other materials, highlighting their dual role in improving water purification efficiency. Over the past decades, significant progress has been made in understanding the photocatalytic properties of polymers, including organic, inorganic, and composite materials, and their efficacy in degrading pharmaceuticals. Some of the most commonly used polymers, such as polyaniline, poly(p-phenylene vinylene), polyethylene oxide, and polypyrole, and their properties have been reviewed in detail. Physical modification techniques (mechanical blending and extrusion processing) and chemical modification techniques (nanocomposite formation, plasma modification techniques, surface functionalization, and cross-linking) have been discussed as appropriate for modifying polymers in order to increase their photocatalytic activity. This review examines the latest research findings, including the development of novel polymer-based photocatalysts and their application in the removal of pharmaceutical compounds, as well as optimization strategies for enhancing their performance. Additionally, challenges and future directions in this field are discussed to guide further research efforts. Full article
(This article belongs to the Special Issue Advanced Catalytic Materials and Processes for Water/Wastewater Treatment)
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19 pages, 2772 KiB  
Article
Staphylococcus aureus Alkaline Protease: A Promising Additive for Industrial Detergents
by Mona Alonazi
Catalysts 2024, 14(7), 446; https://doi.org/10.3390/catal14070446 - 12 Jul 2024
Viewed by 776
Abstract
A novel alkaline serine protease, derived from the Staphylococcus aureus strain ALA1 previously isolated from dromedary milk, was subjected to purification and characterization. Optimal protease production occurred under specific culture conditions. The purified protease, designated S. aureus Pr with a molecular mass of [...] Read more.
A novel alkaline serine protease, derived from the Staphylococcus aureus strain ALA1 previously isolated from dromedary milk, was subjected to purification and characterization. Optimal protease production occurred under specific culture conditions. The purified protease, designated S. aureus Pr with a molecular mass of 23,662 Da and an N-terminal sequence, showed an approximately 89% similar identity with those of other Staphylococcus strains. It exhibited its highest enzymatic activity at a pH of 10.0 and 60 °C in the presence of 3 mM Ca2+. Remarkable thermostability was observed at temperatures up to 70 °C and within a pH range of 6.0 to 10.0 for 2 h. The presence of Ca2+ or Mg2+ and Zn2+ significantly enhanced both enzymatic activity and thermal stability. Additionally, notable stability was demonstrated in the presence of reducing and chaotropic agents as well as in surfactants, oxidizing agents, and organic solvents commonly found in detergent compositions. This highlights the enzyme’s potential as a versatile biocatalyst, especially in detergents. Its stability and compatibility with laundry detergents matched Alcalase 2.5 L, type Dx, and the Stearothermophilus protease, used as controls. Collectively, this study investigated the potential utilization of S. aureus Pr in industrial detergents as an excellent candidate for incorporation as an additive in detergent formulations. Full article
(This article belongs to the Special Issue Applications of Catalytic Reactions in Promoting the Health of Organisms)
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12 pages, 3028 KiB  
Article
Mixed Oxides as Catalysts for the Condensation of Cyclohexanol and Benzaldehyde to Obtain a Claisen–Schmidt Condensation Product
by Tanya Stoylkova, Tsveta Stanimirova, Christo D. Chanev, Petya Petrova and Kristina Metodieva
Catalysts 2024, 14(7), 445; https://doi.org/10.3390/catal14070445 - 11 Jul 2024
Viewed by 676
Abstract
Acid–base M2+MgAlO and M2+AlO mixed oxides (where M2+ = Mg, Cu, Co, Zn, and Ni) were obtained by thermal decomposition of the corresponding layered double hydroxide (LDH) precursors and used as catalysts for cyclohexanol and benzaldehyde condensation under [...] Read more.
Acid–base M2+MgAlO and M2+AlO mixed oxides (where M2+ = Mg, Cu, Co, Zn, and Ni) were obtained by thermal decomposition of the corresponding layered double hydroxide (LDH) precursors and used as catalysts for cyclohexanol and benzaldehyde condensation under solvent-free conditions. The catalysts were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and temperature-programmed desorption of CO2 (TPD-CO2). Gas chromatography–mass spectroscopy (GC/MS) was used for the identification and quantification of the product mixtures. In the reaction of cyclohexanol and benzaldehyde on M2+MgAlO and MgAlO catalysts, a 2,6-dibenzylidene-cyclohexanone was obtained as the main product as a result of consecutive one-pot dehydrogenation of cyclohexanol to cyclohexanone and subsequent Claisen–Schmidt condensation. In the reaction mixture obtained in the presence of NiAlO, CoAlO, and ZnAlO catalysts, a cyclohexyl ester of 6-hydroxyhexanoic acid was detected together with the main product. This is most likely a by-product obtained after the oxidation, ring opening, and subsequent esterification of the cyclohexanol. Full article
(This article belongs to the Special Issue Layered Double Hydroxide-Based Catalysts for Advanced Chemical Technologies)
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4 pages, 164 KiB  
Editorial
Nanocatalysts for the Degradation of Refractory Pollutants
by Sheng Guo, Yazi Liu and Jun Li
Catalysts 2024, 14(7), 444; https://doi.org/10.3390/catal14070444 - 11 Jul 2024
Viewed by 570
Abstract
The rapid development of industrialization has resulted in the excessive emission of hazardous contaminants into our water and air resources, adversely affecting both health and the environment [...] Full article
(This article belongs to the Special Issue Nanocatalysts for the Degradation of Refractory Pollutants)
16 pages, 17079 KiB  
Article
Structural Effect of Cu-Mn/Al2O3 Catalysts on Enhancing Toluene Combustion Performance: Molecular Structure of Polyols and Hydrothermal Treatment
by Junjie Li, Wenjing Chen, Chenghua Xu, Xiaoxiao Hou and Xiaodong Hu
Catalysts 2024, 14(7), 443; https://doi.org/10.3390/catal14070443 - 11 Jul 2024
Viewed by 588
Abstract
This study presents a series of Cu-Mn/Al2O3 catalysts prepared by the polyol method to improve the toluene combustion process. The catalytic activity evaluation results showed that the different polyols have a great influence on catalyst activity, in which the catalyst [...] Read more.
This study presents a series of Cu-Mn/Al2O3 catalysts prepared by the polyol method to improve the toluene combustion process. The catalytic activity evaluation results showed that the different polyols have a great influence on catalyst activity, in which the catalyst prepared with glycerol through a hydrothermal reaction at 90 °C displayed the highest catalytic activity. The lowest T90 and T50 values could be achieved by CMA-GL-90 with 260 and 237 °C, respectively. Moreover, the XRD and BET results showed that the hydrothermal treatment was more favorable with Cu-Mn crystal formation, and an abundance of mesopores remained in all catalysts with a high specific surface area from 94.37 to 123.03 m2·g−1. The morphology analysis results by SEM and TEM indicated that employing glycerol coupled with hydrothermal treatment at 90 °C could enhance the formation of CuMn2O4 spinel. The toluene catalytic combustion mechanism of Cu-Mn/Al2O3 catalysts was discussed based on XPS and H2-TPR, and a high atomic ratio of Mn3+ could be obtained with 51.03%, and the ratio of Oads/Olatt also increased to 2.85 in CMA-GL-90. The increase in Mn3+ species and oxygen vacancies on the surface of catalysts exhibited excellent activity and stability for toluene combustion. These findings offer valuable insights for optimizing the design and application of Cu-Mn/Al2O3 catalysts in addressing the catalytic oxidation reactions of organic volatile compounds. Full article
(This article belongs to the Special Issue Heterogeneous Catalysis and Advanced Oxidation Processes (AOP) for Environmental Protection (VOCs Oxidation, Air and Water Purification), 2nd Edition)
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15 pages, 9817 KiB  
Article
Enhanced Photocatalytic Performances of SnS2/TiO2 Composites via a Charge Separation Following Z-Scheme at the SnS2/TiO2{101} Facets
by Nkenku Carl, Muhammad Fiaz, Hyun-Seok Oh and Yu-Kwon Kim
Catalysts 2024, 14(7), 442; https://doi.org/10.3390/catal14070442 - 10 Jul 2024
Cited by 1 | Viewed by 1147
Abstract
The formation of heterojunctions for efficient charge separation has been practiced for the preparation of efficient semiconductor-based photocatalysts for applications such as hydrogen production and environmental remediation. In this study, we synthesized a composite structure with a heterojunction between SnS2 and TiO [...] Read more.
The formation of heterojunctions for efficient charge separation has been practiced for the preparation of efficient semiconductor-based photocatalysts for applications such as hydrogen production and environmental remediation. In this study, we synthesized a composite structure with a heterojunction between SnS2 and TiO2 through a microwave-assisted hydrothermal process, in which SnS2 nanoparticles grew on nanocrystalline TiO2 nanosheets preferentially at the exposed {101} facets. Appropriate exposure of the {001} and {101} facets of the TiO2 nanosheet in the composite with a preferential growth of SnS2 nanoparticles at the {101} facets was the origin of the charge separation following a direct Z-scheme mechanism to result in enhanced photocatalytic performances in photodegradation of organic dyes such as methylene blue (MB) and rhodamine B (RhB) compared to that of SnS2 and TiO2 alone. A plot of photodegradation rates vs. SnS2 ratios in the composites gave an overall volcano-shaped curve with a maximum at the SnS2 ratio of about 33% at which small SnS2 nanoparticles were populated at the {101} facets of the TiO2 nanosheets with a high surface area (118.2 m2g−1). Our results suggest the microwave-assisted hydrothermal process can be a good synthetic approach for composite-based photocatalysts with a preferential heterojunction structure. Full article
(This article belongs to the Special Issue Recent Advances in Environment and Energy Catalysis)
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11 pages, 2358 KiB  
Article
Tuning a Cr-Catalyzed Ethylene Oligomerization Product Profile via a Rational Design of the N-aryl PNP Ligands
by Samir Barman, E. A. Jaseer, Nestor Garcia, Mohamed Elanany, Motaz Khawaji, Niladri Maity and Abdulrahman Musa
Catalysts 2024, 14(7), 441; https://doi.org/10.3390/catal14070441 - 10 Jul 2024
Viewed by 713
Abstract
An approach towards incorporating varied degrees of steric profiles around the ligand’s backbone, which were envisaged to alter the catalytic paths leading to targeted 1-C8/1-C6 olefin products, were explored. Cr-pre-catalysts designed with PNP ligands comprising a fused aryl moiety were [...] Read more.
An approach towards incorporating varied degrees of steric profiles around the ligand’s backbone, which were envisaged to alter the catalytic paths leading to targeted 1-C8/1-C6 olefin products, were explored. Cr-pre-catalysts designed with PNP ligands comprising a fused aryl moiety were delivered at a relatively higher C8 olefin selectivity (up to 74.6 wt% and C8/C6 of 3.4) when the N-connection to the aromatic unit was placed at the 2-position. A relatively higher C6 olefin selectivity (up to 33.7 wt% and C8/C6 of 1.9) was achieved with the PNP unit anchored at the 1- or 6-position. Based on detailed catalytic studies, we confirm the fact that by introducing a controlled degree of bulkiness on the N-site through a judicious selection of the N-aryl moiety of different sizes, the selectivity of the targeted olefin product could be tuned in a rational manner. Full article
(This article belongs to the Special Issue Advanced Catalysis for Energy and Environmental Applications)
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11 pages, 2861 KiB  
Article
Theoretical Study of Reversible Hydrogenation of CO2 to Formate Catalyzed by Ru(II)–PN5P, Fe(II)–PN5P, and Mn(I)–PN5P Complexes: The Effect of the Transition Metal Center
by Lingqiang Meng, Lihua Yao and Jun Li
Catalysts 2024, 14(7), 440; https://doi.org/10.3390/catal14070440 - 9 Jul 2024
Viewed by 769
Abstract
In 2022, Beller and coworkers achieved the reversible hydrogenation of CO2 to formic acid using a Mn(I)–PN5P complex with excellent activity and reusability of the catalyst. To understand the detailed mechanism for the reversible hydrogen release–storage process, especially the effects [...] Read more.
In 2022, Beller and coworkers achieved the reversible hydrogenation of CO2 to formic acid using a Mn(I)–PN5P complex with excellent activity and reusability of the catalyst. To understand the detailed mechanism for the reversible hydrogen release–storage process, especially the effects of the transition metal center in this process, we employed DFT calculations according to which Ru(II) and Fe(II) are considered as two alternatives to the Mn(I) center. Our computational results showed that the production of formic acid from CO2 hydrogenation is not thermodynamically favorable. The reversible hydrogen release–storage process actually occurs between CO2/H2 and formate rather than formic acid. Moreover, Mn(I) might not be a unique active metal for the reversible hydrogenation of CO2 to formate; Ru(II) would be a better option. Full article
(This article belongs to the Special Issue Catalysis for Selective Hydrogenation of CO and CO2, 2nd Edition)
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2 pages, 153 KiB  
Editorial
Exclusive Review Papers in Catalytic Materials
by Carolina Belver
Catalysts 2024, 14(7), 439; https://doi.org/10.3390/catal14070439 - 9 Jul 2024
Viewed by 516
Abstract
Catalytic materials exist in several forms and can be prepared using different methodologies and protocols [...] Full article
(This article belongs to the Special Issue Exclusive Review Papers in Catalytic Materials)
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