Synthesis and Application of Novel Nanocatalysts

A special issue of Processes (ISSN 2227-9717). This special issue belongs to the section "Catalysis Enhanced Processes".

Deadline for manuscript submissions: closed (31 March 2023) | Viewed by 33075

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Guest Editor
Department of Chemistry, Pusan National University, Busan 46241, Korea
Interests: synthesis of new nanocatalysts & applications for organic reactions; fabrications & applications of nanomaterials; organometallic chemistry of f-and d-block transition metal complexes; new organometallic catalysts for efficient organic synthesis; transition-metal promoted organic synthesis and homogeneous catalysis
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Guest Editor
Department of Physics, Pusan National University, Busan 46241, Korea
Interests: nanostructure and nanomaterial characterization; thin film/interface science (magnetism); neutron/X-ray scattering; thin film growth & characterization

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Guest Editor
Clean Fuel Laboratory, Korea Institute of Energy Research, Dajeon 305-343, Korea
Interests: heterogeneous materials; nano catalysts; fundamental study of synthesis and morphology control of nanomaterials

Special Issue Information

Dear Colleagues,

Recently, transition metal nanoparticles have been of considerable interest as catalysts in organic and inorganic transformations. Being small in size is expected to increase the nanoparticle surface tension. This makes surface atoms very active. In many cases, the inherent advantages of heterogeneous catalysts, such as the ease of product separation and catalyst recycling, are observed. However, the activity and selectivity of catalyst nanoparticles are strongly dependent on their size, shape, surface structure, and their bulk and surface composition. A large number of review articles provide extensive coverage of the subject. Moreover, the preparation, characterization, and mechanism of formation of transition metal nanoparticles have been extensively reviewed.

Homogeneous nanosized catalysts are already well known that exhibit better catalytic activity than heterogeneous catalysts because of easy solubility in reaction media and access to all catalytic sites. However, these homogeneous catalysts are rarely separated and recovered from the reaction systems efficiently by centrifugation methods and traditional filtration. For example, palladium nanoparticles have had problems in the reuse of catalysts and aggregation, thereby resulting in a decrease of catalytic activity. Catalysts in a distinct phase with respect to the reaction medium account for the major advantage of the heterogeneous catalysts over homogeneous catalysts, as it makes the separation and reutilization of heterogeneous catalysts simple and cheap compared to homogeneous catalysts. To overcome the drawback of these homogeneous catalysis problems, many efforts have been made to achieve the immobilization of a homogeneous nanocatalyst onto various insoluble support, activated carbon, polymer, alumina, porous silica materials with high surface area, zeolites, layered double hydroxides and magnetic nanoparticles. Recovering and recycling catalysts that are quite expensive result in positive effects from an economic and environmental point of view. The recognition of these limitations of homogeneous catalysts resulted in attempts to heterogenize homogeneous catalysts. However, a major drawback of heterogenized catalysts is the leaching of the catalyst during its use and recycling, leading to deactivation. A goal of catalyst research is to combine the advantages of both homogeneous (activity and selectivity) and heterogeneous catalytic systems (recycling catalyst), resulting in overcoming these problems.

All experimental works falling within the scope of this Special Issue, including original research papers, short communications, review articles, and perspective articles, are invited for submission.

This Special Issue on the “Synthesis and Application of Novel Nanocatalysts” aims to curate novel advances in the development and application of nanocatalysts to address longstanding challenges in heterogeneous catalysts. Topics include, but are not limited to:

  • Development of new nanocatalysts and applications for organic reactions;
  • Developments in hybrid metal nanocatalysts for organic reactions;
  • Development of heterogeneous catalysis;
  • Fabrications and applications of nanocatalysts.

Prof. Dr. Kang Hyun Park
Prof. Dr. Sungkyun Park
Dr. Ji Chan Park
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Processes is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Nanocatalysts
  • Nanocomposites
  • Multicomponent
  • Heterogenous
  • Metal

Published Papers (10 papers)

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Research

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19 pages, 2588 KiB  
Article
Catalytic Hydrogenation of Nitrate over Immobilized Nanocatalysts in a Multi-Phase Continuous Reaction System: System Performance, Characterization and Optimization
by Ana Sofia G. G. Santos, João Restivo, Carla Alexandra Orge, Manuel Fernando R. Pereira and Olívia Salomé G. P. Soares
Processes 2023, 11(9), 2692; https://doi.org/10.3390/pr11092692 - 8 Sep 2023
Cited by 1 | Viewed by 1045
Abstract
Nitrate catalytic reduction in a continuous system was studied in the presence of Pd-Cu macrostructured catalysts synthesized through a novel washcoating methodology of the pre-formed bimetallic powder catalyst. The present work aims to understand the behavior of the macrostructured bimetallic catalyst in the [...] Read more.
Nitrate catalytic reduction in a continuous system was studied in the presence of Pd-Cu macrostructured catalysts synthesized through a novel washcoating methodology of the pre-formed bimetallic powder catalyst. The present work aims to understand the behavior of the macrostructured bimetallic catalyst in the presence of different reaction conditions in order to achieve the design of an optimized facility that can produce the best catalytic results: maximum NO3 conversion with enhanced N2 selectivity. The residence time of the inlet solution and the catalyst concentration in the reactor proved to be the parameters that most influenced the conversion and selectivity due to the important role that these parameters play in the hydrodynamic conditions of the reactor. A higher loading of catalyst and lower inlet flow rates allow promoting a higher contact time between the three phases that participate in the reaction (G-L-S). The most efficient reaction conditions (three pieces of the macrostructured catalyst, liquid flow rate of 10 mL min−1, and a total gas flow rate of 200 Ncm3 min−1 (1:1 H2:CO2)) allowed obtaining an NO3 conversion of 51% with a corresponding N2 selectivity of 23%. Also, the conversion results strongly depended on the total gas flow rate used during the reaction since this assists the mixing between the three phases and promotes a greater contact that will contribute to enhanced catalytic results. Full article
(This article belongs to the Special Issue Synthesis and Application of Novel Nanocatalysts)
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14 pages, 5097 KiB  
Article
Effective Malachite Green Degradation over the Noble Metal-Doped and MOF-Coupled CsSnBr3 Nanocomposite Catalyst
by Bohan Ai, Mingsheng Luo and Iltaf Khan
Processes 2023, 11(5), 1398; https://doi.org/10.3390/pr11051398 - 5 May 2023
Cited by 6 | Viewed by 1724
Abstract
Environmental protection laws require effective and green solutions to tackle water and air pollution issues. For this purpose, perovskite photocatalytic materials have proven to be a promising solution. In this study, CsSnBr3 perovskite, coupled with ZIF-67 and decorated with noble metal Au, [...] Read more.
Environmental protection laws require effective and green solutions to tackle water and air pollution issues. For this purpose, perovskite photocatalytic materials have proven to be a promising solution. In this study, CsSnBr3 perovskite, coupled with ZIF-67 and decorated with noble metal Au, was shown to effectively enhance the charge separation and increase the light-absorbing capacity, and thus make the photocatalytic reaction more efficient by surface plasmon resonance. Characterization results from XRD, FTIR, and UV-visible diffuse reflectance spectroscopy indicated that a mixture of cubic and tetragonal crystalline phases was found in the prepared catalyst material. XPS also revealed that in the presence of two oxidation states for tin (Sn), the Au 4f XPS peaks of Au NPs coincided with those retained in colloidal Au particles. Using malachite green as a model compound, organic pollutant photocatalytic degradation tests proved that CsSnBr3 generated good photocatalytic activity for aromatic pollutant degradation. In this research, the synthesized 4Au-7ZIF-CsSnBr3 catalyst yielded an MG degradation rate twice as high as the unpromoted CsPbBr3. Full article
(This article belongs to the Special Issue Synthesis and Application of Novel Nanocatalysts)
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8 pages, 1909 KiB  
Communication
Co-Precipitated Mn0.15Ce0.85O2−δ Catalysts for NO Oxidation: Manganese Precursors and Mn-Ce Interactions
by Yuxi Gao, Baofang Jin, Xiaodong Wu, Zhenguo Li, Rui Ran and Duan Weng
Processes 2022, 10(12), 2562; https://doi.org/10.3390/pr10122562 - 1 Dec 2022
Cited by 1 | Viewed by 1028
Abstract
Two Mn0.15Ce0.85O2−δ mixed oxides were synthesized by a co-precipitation method using Mn(NO3)2 and KMnO4 as the manganese precursors, respectively. Structural analyses by X-ray powder diffraction and Raman spectroscopy reveal the formation of MnOx [...] Read more.
Two Mn0.15Ce0.85O2−δ mixed oxides were synthesized by a co-precipitation method using Mn(NO3)2 and KMnO4 as the manganese precursors, respectively. Structural analyses by X-ray powder diffraction and Raman spectroscopy reveal the formation of MnOx-CeO2 solid solutions. The Mn0.15Ce0.85O2−δ catalyst prepared from the high-valent manganese precursor exhibits higher activity for the catalytic oxidation of NO. The advantage of KMnO4 is related to the improved redox property of the catalyst as supported by H2 temperature-programmed reduction (TPR) and O2 temperature-programmed desorption (TPD). The Mn-Ce interactions create more Mn4+, Ce3+ and oxygen vacancies on the KMnO4-synthesized mixed oxides based on the Raman and X-ray photoelectron spectra (XPS). Full article
(This article belongs to the Special Issue Synthesis and Application of Novel Nanocatalysts)
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14 pages, 3885 KiB  
Article
In Situ DRIFTS Study of Single-Atom, 2D, and 3D Pt on γ-Al2O3 Nanoflakes and Nanowires for C2H4 Oxidation
by Shengpan Peng, Ziran Ma, Jing Ma, Hongyan Wang, Kai Ren, Xiaodong Wu and Baodong Wang
Processes 2022, 10(9), 1773; https://doi.org/10.3390/pr10091773 - 4 Sep 2022
Cited by 2 | Viewed by 1562
Abstract
Up to now, a great number of catalysts have been reported that are active in the oxidation of volatile organic compounds (VOCs). However, supported noble-metal catalysts (especially Pt-based catalysts) are still the most excellent ones for this reaction. In this study, Pt species [...] Read more.
Up to now, a great number of catalysts have been reported that are active in the oxidation of volatile organic compounds (VOCs). However, supported noble-metal catalysts (especially Pt-based catalysts) are still the most excellent ones for this reaction. In this study, Pt species supported on γ-Al2O3 and ranging from single-atom sites to clusters (less than 1 nm) and 1–2 nm nanoparticles were prepared and investigated for oxidizing C2H4. The Pt-loaded γ-Al2O3 nanoflakes (PtAl-NF) and Pt-loaded γ-Al2O3 nanowires (PtAl-NW) were successfully prepared. The samples were characterized using XRD, TEM, XPS, HAADF-STEM, and in situ DRIFTS. Based on in situ DRIFTS, a simple surface reaction mechanism was developed. The stable intermediates CO on single-atom Pt, subnanometer Pt particles, and fully exposed Pt clusters could be explained by the strong binding of CO molecule poisoning Pt sites. Moreover, the oxidation of C2H4 was best achieved by Pt particles that were 1–2 nm in size and the catalytic activity of PtAl-NF was better when it had less Pt. Lastly, the most exposed (110) facets of γ-Al2O3 nanoflakes were more resistant to water than the majorly exposed (100) facets of γ-Al2O3 nanowires. Full article
(This article belongs to the Special Issue Synthesis and Application of Novel Nanocatalysts)
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12 pages, 4567 KiB  
Article
Biomass-Derived Activated Carbon as a Catalyst for the Effective Degradation of Rhodamine B dye
by Shamim Ahmed Hira, Mohammad Yusuf, Dicky Annas, Hu Shi Hui and Kang Hyun Park
Processes 2020, 8(8), 926; https://doi.org/10.3390/pr8080926 - 2 Aug 2020
Cited by 16 | Viewed by 3823
Abstract
Activated carbon (AC) was fabricated from carrot waste using ZnCl2 as the activating agent and calcined at 700 °C for 2 h in a tube furnace. The as-synthesized AC was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission [...] Read more.
Activated carbon (AC) was fabricated from carrot waste using ZnCl2 as the activating agent and calcined at 700 °C for 2 h in a tube furnace. The as-synthesized AC was characterized using Fourier-transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller analysis; the results revealed that it exhibited a high specific surface area and high porosity. Moreover, this material displayed superior catalytic activity for the degradation of toxic Rhodamine B (RhB) dye. Rate constant for the degradation of RhB was ascertained at different experimental conditions. Lastly, we used the Arrhenius equation and determined that the activation energy for the decomposition of RhB using AC was approximately 35.9 kJ mol−1, which was very low. Hopefully it will create a great platform for the degradation of other toxic dye in near future. Full article
(This article belongs to the Special Issue Synthesis and Application of Novel Nanocatalysts)
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16 pages, 5455 KiB  
Article
Hierarchical Cs–Pollucite Nanozeolite Modified with Novel Organosilane as an Excellent Solid Base Catalyst for Claisen–Schmidt Condensation of Benzaldehyde and Acetophenone
by Aleid Ghadah Mohammad S., Fitri Khoerunnisa, Severinne Rigolet, T. Jean Daou, Tau-Chuan Ling and Eng-Poh Ng
Processes 2020, 8(1), 96; https://doi.org/10.3390/pr8010096 - 10 Jan 2020
Cited by 7 | Viewed by 3340
Abstract
Cs–pollucite can be a potential solid base catalyst due to the presence of (Si-O-Al)Cs+ basic sites. However, it severely suffers from molecular diffusion and pore accessibility problems due to its small micropore opening. Herein, we report the use of new [...] Read more.
Cs–pollucite can be a potential solid base catalyst due to the presence of (Si-O-Al)Cs+ basic sites. However, it severely suffers from molecular diffusion and pore accessibility problems due to its small micropore opening. Herein, we report the use of new organosilane, viz. dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride (TPOAC), as a promising pore-expanding agent to develop the hierarchical structure in nanosized Cs–pollucite. In respect to this, four different amounts of TPOAC were added during the synthesis of hierarchical Cs–pollucite (CP-x, x = 0, 0.3, 1.0, or 2.0, where x is the molar ratio of TPOAC) in order to investigate the effects of TPOAC in the crystallization process of Cs–pollucite. The results show that an addition of TPOAC altered the physico-chemical and morphological properties of hierarchical Cs–pollucite, such as the crystallinity, crystallite size, pore size distribution, surface areas, pore volume, and surface basicity. The prepared solids were also tested in Claisen–Schmidt condensation of benzaldehyde and acetophenone, where 82.2% of the conversion and 100% selectivity to chalcone were achieved by the CP-2.0 catalyst using non-microwave instant heating (200 °C, 100 min). The hierarchical CP-2.0 nanocatalyst also showed better catalytic performance than other homogenous and heterogeneous catalysts and displayed a high catalyst reusability with no significant deterioration in the catalytic performance even after five consecutive reaction runs. Full article
(This article belongs to the Special Issue Synthesis and Application of Novel Nanocatalysts)
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12 pages, 4561 KiB  
Article
Preparation and Performance Analysis of Graphite Additive/Paraffin Composite Phase Change Materials
by Wei Li, Yan Dong, Xu Zhang and Xueling Liu
Processes 2019, 7(7), 447; https://doi.org/10.3390/pr7070447 - 13 Jul 2019
Cited by 27 | Viewed by 5592
Abstract
In the thermal energy storage system, the thermal properties of phase change materials (PCM) have a great influence on the system performance. In this paper, paraffin-based composite phase change material with different graphite additive (expanded graphite, EG; graphene, GR; and graphene oxide, GO) [...] Read more.
In the thermal energy storage system, the thermal properties of phase change materials (PCM) have a great influence on the system performance. In this paper, paraffin-based composite phase change material with different graphite additive (expanded graphite, EG; graphene, GR; and graphene oxide, GO) and different concentrations (0.5 to 2.0%) are manufactured by a two-step method combining mechanical agitation and ultrasonic vibration. The characteristics of charge/discharge processes are studied, and the thermophysical properties are measured by T-history method. The experimental results show that the thermal conductivity and heat charge rate of the composite PCM are effectively improved by adding the graphite additive to the PCM, and the addition of additives can improve the melting point of the material. When the same graphite additive is added, the higher the concentration, the higher the thermal conductivity of the composite PCM, and the latent heat decreases with the increase of concentration. When adding the same amount of carbon additives, the graphene/paraffin composite PCM has the highest heat charge/discharge rate and thermal conductivity. It is finally concluded that graphene is the most promising candidate for heat transfer enhancement of paraffin among three carbon additives even though the EG-based composite PCM gives relatively high latent heat. Full article
(This article belongs to the Special Issue Synthesis and Application of Novel Nanocatalysts)
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16 pages, 4141 KiB  
Article
High-Performance Chlorine-Doped Cu2O Catalysts for the Ethynylation of Formaldehyde
by Jie Gao, Guofeng Yang, Haitao Li, Mei Dong, Zhipeng Wang and Zhikai Li
Processes 2019, 7(4), 198; https://doi.org/10.3390/pr7040198 - 6 Apr 2019
Cited by 10 | Viewed by 4360
Abstract
The in situ formed Cu+ species serve as active sites in the ethynylation of formaldehyde. The key problem that needs to be solved in this process is how to avoid excessive reduction of Cu2+ to inactive metallic Cu, which tends to [...] Read more.
The in situ formed Cu+ species serve as active sites in the ethynylation of formaldehyde. The key problem that needs to be solved in this process is how to avoid excessive reduction of Cu2+ to inactive metallic Cu, which tends to decrease the catalytic activity. In this work, Cl-modified Cu2O catalysts with different Cl content were prepared by co-precipitation. The characterization results demonstrated that Cl remained in the lattice structure of Cu2O, inducing the expansion of the Cu2O lattice and the enhancement of the Cu–O bond strength. Consequently, the reduction of Cu+ to Cu0 was effectively prevented in reductive media. Moreover, the activity and stability of Cu2O were significantly improved. The Cl modification increased the yield of 1,4-butynediol (BD) from 73% to 94% at a reaction temperature of 90 °C. More importantly, the BD yield of Cl modified Cu2O was still as high as 86% during the ten-cycle experiment, whereas the BD yield of Cu2O in the absence of Cl decreased sharply to 17% at the same reaction conditions. This work provides a simple strategy to stabilize Cu+ in reductive media. Full article
(This article belongs to the Special Issue Synthesis and Application of Novel Nanocatalysts)
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Review

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67 pages, 10665 KiB  
Review
Recent Progress of Non-Pt Catalysts for Oxygen Reduction Reaction in Fuel Cells
by Qing Chen, Zhou Zhang, Ruiquan Zhang, Maocong Hu, Ling Shi and Zhenhua Yao
Processes 2023, 11(2), 361; https://doi.org/10.3390/pr11020361 - 23 Jan 2023
Cited by 11 | Viewed by 4394
Abstract
In recent years, non-Pt-based ORR catalysts have been developing rapidly and have achieved performance comparable to or even surpassing Pt precious metal catalysts in specific reactions, offering new possibilities for Pt-based catalyst replacement and showing great promise for application. This paper reviews the [...] Read more.
In recent years, non-Pt-based ORR catalysts have been developing rapidly and have achieved performance comparable to or even surpassing Pt precious metal catalysts in specific reactions, offering new possibilities for Pt-based catalyst replacement and showing great promise for application. This paper reviews the recent research progress of non-Pt-based fuel cell ORR catalysts. The latest research progress of non-Pt-based ORR SACs (including single metal active site ORR SACs, multi-metal active site ORR SACs, and non-Pt-based noble metal catalyst ORR SACs), non-metallic ORR catalysts, alloy-based ORR catalysts, high-entropy alloy ORR catalysts, and other non-Pt-based fuel cell ORR catalysts are presented in detail. This paper discusses in detail the synthesis methods, characterization means, optimization of performance, and application prospects of these non-Pt-based ORR catalysts. In addition, this review details the excellent performance of these catalysts in terms of compositional and structural controllability, electrical conductivity, and chemical stability, as well as their ability to exhibit ORR activity comparable to that of commercial Pt/C catalysts. This field is full of opportunities and challenges. In summary, non-Pt-based fuel cells show great potential in ORR. With the continuous improvement of preparation and characterization technologies, catalysts have broad application and market prospects. In addition, the development trend of non-precious metal fuel cell catalysts is reviewed. Full article
(This article belongs to the Special Issue Synthesis and Application of Novel Nanocatalysts)
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31 pages, 18201 KiB  
Review
Recent Novel Hybrid Pd–Fe3O4 Nanoparticles as Catalysts for Various C–C Coupling Reactions
by Sanha Jang, Shamim Ahmed Hira, Dicky Annas, Sehwan Song, Mohammad Yusuf, Ji Chan Park, Sungkyun Park and Kang Hyun Park
Processes 2019, 7(7), 422; https://doi.org/10.3390/pr7070422 - 3 Jul 2019
Cited by 18 | Viewed by 5224
Abstract
The use of nanostructure materials as heterogeneous catalysts in the synthesis of organic compounds have been receiving more attention in the rapid developing area of nanotechnology. In this review, we mainly focused on our own work on the synthesis of hybrid palladium–iron oxide [...] Read more.
The use of nanostructure materials as heterogeneous catalysts in the synthesis of organic compounds have been receiving more attention in the rapid developing area of nanotechnology. In this review, we mainly focused on our own work on the synthesis of hybrid palladium–iron oxide nanoparticles. We discuss the synthesis of Pd–Fe3O4—both morphology-controlled synthesis of Pd–Fe3O4 and transition metal-loaded Pd–Fe3O4—as well as its application in various C–C coupling reactions. In the case of rose-like Pd–Fe3O4 hybrid nanoparticles, thermal decomposition can be used instead of oxidants or reductants, and morphology can be easily controlled. We have developed a method for the synthesis of nanoparticles that is facile and eco-friendly. The catalyst was recyclable for up to five continual cycles without significant loss of catalytic activity and may provide a great platform as a catalyst for other organic reactions in the near future. Full article
(This article belongs to the Special Issue Synthesis and Application of Novel Nanocatalysts)
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