Special Issue "Nanomaterials in Catalysis Applications"

A special issue of Catalysts (ISSN 2073-4344). This special issue belongs to the section "Catalytic Materials".

Deadline for manuscript submissions: closed (31 December 2021) | Viewed by 13639

Special Issue Editors

Prof. Dr. Ioannis V. Yentekakis
E-Mail Website
Guest Editor
Physical Chemistry and Chemical Processes Laboratory, School of Environmental Engineering, TECHNICAL UNIVERSITY OF CRETE (TUC), 73100 Chania, Crete, Greece
Interests: physical chemistry; heterogeneous catalysis; environmental catalysis; catalyst promotion; chemical reaction engineering and thermodynamics; surfaces and interfaces; electrochemistry; fuel cells; nanomaterials and nanotechnology
Special Issues, Collections and Topics in MDPI journals
Prof. Dr. Michael A. Karakassides
E-Mail Website
Guest Editor
Department of Materials Science and Engineering, University of Ioannina, GR-45110 Ioannina, Greece
Interests: catalysis; nanomaterials and nanotechnology; ceramic; composite and porous materials; oxide glasses; hybrid materials; mesoporous and phyllomorphic materials based on silicon or carbon; clay based materials; photocatalytic materials; magnetic oxide nanoparticles and zero valence iron; activated carbon materials produced from biomass; structure and physicochemical properties of materials with vibrational spectroscopic techniques; thermal analysis; porosimetry
Prof. Dr. Dimitrios Gournis
E-Mail Website
Guest Editor
Department of Materials Science and Engineering, University of Ioannina, GR-45110 Ioannina, Greece
Interests: catalysis; nanomaterials and nanotechnology; chemistry of phyllomorphous (2D) materials (in particular inorganic layered structures, clay-based materials (clays, pillared clays, organo-clays, LDHs), carbon layered structures, TMDs, germanane etc.); carbon nanostructures (carbon nanotubes, fullerenes, graphene, graphite oxide, carbon dots, molecular diamonds); hybrid organic–inorganic nanocomposites; mesoporous materials; metallic (magnetic or semiconducting) nanoparticles and biocatalysts

Special Issue Information

Dear Colleagues,

Great advances have been recorded in heterogeneous catalysis and/or electrocatalysis as a result of the ongoing progress in nanotechnology that provides efficient approaches and advanced methods for the design of nano-structured composite materials subjected to specific nanomorphologies and enhanced metal–metal and metal–support interactions. Surface-induced and/or support-mediated promotion of catalytic performance through metal–metal and metal–support interactions, as well as surface morphology (size/shape of catalyst nanoparticles), are issues that have a crucial role in determining and improving the efficiency and robustness of heterogeneous catalytic materials for specific applications. Fine-tuning of critical physicochemical properties of the materials, such as electron affinity (work function), oxidation state, and morphology of nanoparticles is therefore achieved, enabling catalytic activity, selectivity and time-on-stream stability optimization of the materials for reactions with high environmental and energy importance.

Apparently, heterogeneous catalysis and electrocatalysis played, play, and will continue to play a major role in industrial processes for large-scale synthesis of commodity chemicals of global importance and in catalytic systems that possess a critical role in energy generation and environmental protection approaches. Among others, such ecofriendly and cost-efficient applications involve, for example, deNOx, deN2O, and VOCs emissions control systems, waste treatment, photocatalytic, biorefinery, CO2 utilization and fuel cells applications, as well as hydrocarbons processing for H2, added-value chemicals and liquid fuels production.

The titled Special Issue aims to cover current experimental studies, in the field of nanomaterials synthesis, their characterization, and application in heterogeneous catalysis and/or electrocatalysis. Therefore, advanced synthesis routes, characterizations, catalytic and electrocatalytic activity/stability evaluation, and fundamental understanding of structure–activity relationships or possible metal–metal and metal–support interactions under desired reactions are very welcome.

Prof. Dr. Ioannis V. Yentekakis
Prof. Dr. Dimitrios Gournis
Prof. Dr. Michael A. Karakassides
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

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. Catalysts 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 2200 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

  • Heterogeneous catalysis and/or electrocatalysis
  • Nano-structured catalytic materials
  • Advanced synthesis routes
  • Structural textural physicochemical characterizations
  • Catalysts promotion
  • Metal–metal and metal–support interactions
  • Nanomaterials for energy applications
  • Nanomaterials for emissions control applications
  • Environmental catalysis applications
  • Nano-structured photocatalysts
  • Electrodes and fuel cells
  • Biocatalysis

Published Papers (8 papers)

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Article
Effect of Operating Conditions on the Performance of Rh/TiO2 Catalyst for the Reaction of LPG Steam Reforming
Catalysts 2021, 11(3), 374; https://doi.org/10.3390/catal11030374 - 12 Mar 2021
Cited by 4 | Viewed by 818
Abstract
The catalytic performance of Rh/TiO2 catalyst was investigated for the reaction of Liquefied Petroleum Gas (LPG) steam reforming with respect to the operating conditions employed. The impacts of reaction temperature, steam/C ratio, Gas Hourly Space Velocity (GHSV), and time were examined and [...] Read more.
The catalytic performance of Rh/TiO2 catalyst was investigated for the reaction of Liquefied Petroleum Gas (LPG) steam reforming with respect to the operating conditions employed. The impacts of reaction temperature, steam/C ratio, Gas Hourly Space Velocity (GHSV), and time were examined and discussed both in the absence and presence of butane in the feed. It was found that the catalytic performance is improved by increasing the reaction temperature, steam content in the feed, and/or by decreasing GHSV. In the presence of butane in the feed, the effect of H2O/C ratio on catalytic performance is prominent, whereas the opposite was observed for the effect of GHSV. The propane conversion curve decreases by adding butane in the feed, indicating that the presence of butane retards propane steam reforming. The investigation of the dynamic response of Rh/TiO2 catalyst to variations of H2O/C ratio showed that neither catalytic activity nor product selectivity is varied with time following abrupt changes of the steam/C ratio between 2 and 7. The catalyst exhibited excellent stability with time-on-stream at 500 and 650 °C. However, a reversible catalyst deactivation seems to be operable when the reaction occurs at 600 °C, resulting in a progressive decrease of propane conversion, which, however, can be completely restored by increasing the temperature to 650 °C in He flow, respectively. The long-term stability of Rh/TiO2 catalyst in the form of pellets showed that this catalyst is not only active and selective but also stable, and therefore, it is a promising catalyst for the reaction of LPG steam reforming. Full article
(This article belongs to the Special Issue Nanomaterials in Catalysis Applications)
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Article
CO2 Methanation on Supported Rh Nanoparticles: The combined Effect of Support Oxygen Storage Capacity and Rh Particle Size
Catalysts 2020, 10(8), 944; https://doi.org/10.3390/catal10080944 - 17 Aug 2020
Cited by 18 | Viewed by 1633
Abstract
CO2 hydrogenation toward methane, a reaction of high environmental and sustainable energy importance, was investigated at 200–600 °C and H2/CO2 = 4/1, over Rh nanoparticles dispersed on supports with different oxygen storage capacity characteristics (γ-Al2O3, [...] Read more.
CO2 hydrogenation toward methane, a reaction of high environmental and sustainable energy importance, was investigated at 200–600 °C and H2/CO2 = 4/1, over Rh nanoparticles dispersed on supports with different oxygen storage capacity characteristics (γ-Al2O3, alumina-ceria-zirconia, and ceria-zirconia). The effects of the support OSC and Rh particle size on reaction behavior under both integral and differential conditions were investigated, to elucidate the combined role of these crucial catalyst design parameters on methanation efficiency. A volcano-type variation of methanation turnover frequency was found in respect to support OSC; Rh/ACZ, with intermediate OSC, was the optimal catalyst. The structure sensitivity of the reaction was found to be a combined function of support OSC and Rh particle size: For Rh/γ-Al2O3 (lack of OSC) methanation was strongly favored on small particles—the opposite for Rh/CZ (high OSC). The findings are promising for rational design and optimization of CO2 methanation catalysts by tailoring the aforementioned characteristics. Full article
(This article belongs to the Special Issue Nanomaterials in Catalysis Applications)
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Article
Synthesis and Characterization of N-Doped SiC Powder with Enhanced Photocatalytic and Photoelectrochemical Performance
Catalysts 2020, 10(7), 769; https://doi.org/10.3390/catal10070769 - 09 Jul 2020
Cited by 8 | Viewed by 925 | Correction
Abstract
Solar-light-driven N-doped 3C–SiC powder was synthesized via a simple one-step combustion route. SiC–N2 photocatalysts exhibited 205.3 μL/(g·h) hydrogen evolution rate, nearly 2 times that of SiC–Ar(120.1 μL/(g·h)), and was much higher than that of SiC nanowires (83.9 μL/(g·h)), SiC nanoparticles (82.8 μL/(g·h)) [...] Read more.
Solar-light-driven N-doped 3C–SiC powder was synthesized via a simple one-step combustion route. SiC–N2 photocatalysts exhibited 205.3 μL/(g·h) hydrogen evolution rate, nearly 2 times that of SiC–Ar(120.1 μL/(g·h)), and was much higher than that of SiC nanowires (83.9 μL/(g·h)), SiC nanoparticles (82.8 μL/(g·h)) as well as the B-doped SiC photocatalysts(166 μL/(g·h)). In cyclic tests, N-doped SiC also performed excellent photocatalytic durability and good structural stability. It can be concluded that the influence of N-doping introduced defects into the SiC photocatalyst by occupation and mixed phase structure, transformed the band structure into the direct band gap, and formed a shallow donor level for trapping holes. Consequently, higher photocatalytic activities and lower recombination was achieved. Furthermore, the carbon on the photocatalyst which was yielded from the substitution of N or which remained after combustion would build constructed efficient interfacial contact with SiC for the quickening of light-driven electron transfer to the surface, and simultaneously strengthen the adsorption capacity and light-harvesting potential. Full article
(This article belongs to the Special Issue Nanomaterials in Catalysis Applications)
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Article
Combining Exsolution and Infiltration for Redox, Low Temperature CH4 Conversion to Syngas
Catalysts 2020, 10(5), 468; https://doi.org/10.3390/catal10050468 - 25 Apr 2020
Cited by 6 | Viewed by 2259
Abstract
Exsolution of surface and bulk nanoparticles in perovskites has been recently employed in chemical looping methane partial oxidation because of the emergent materials’ properties such as oxygen capacity, redox stability, durability, coke resistance and enhanced activity. Here we attempt to further lower the [...] Read more.
Exsolution of surface and bulk nanoparticles in perovskites has been recently employed in chemical looping methane partial oxidation because of the emergent materials’ properties such as oxygen capacity, redox stability, durability, coke resistance and enhanced activity. Here we attempt to further lower the temperature of methane conversion by complementing exsolution with infiltration. We prepare an endo/exo-particle system using exsolution and infiltrate it with minimal amount of Rh (0.1 wt%) in order to functionalize the surface and induce low temperature activity. We achieve a temperature decrease by almost 220 °C and an increase of the activity up to 40%. We also show that the initial microstructure of the perovskite plays a key role in controlling nanoparticle anchorage and carbon deposition. Our results demonstrate that microstructure tuning and surface functionalization are important aspects to consider when designing materials for redox cycling applications. Full article
(This article belongs to the Special Issue Nanomaterials in Catalysis Applications)
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Article
CO2 Hydrogenation to Methanol over La2O3-Promoted CuO/ZnO/Al2O3 Catalysts: A Kinetic and Mechanistic Study
Catalysts 2020, 10(2), 183; https://doi.org/10.3390/catal10020183 - 03 Feb 2020
Cited by 9 | Viewed by 2154
Abstract
The hydrogenation of CO2 to methanol has been investigated over CuO/ZnO/Al2O3 (CZA) catalysts, where a part of the Al2O3 (0, 25, 50, 75, or 100%) was substituted by La2O3. Results of catalytic [...] Read more.
The hydrogenation of CO2 to methanol has been investigated over CuO/ZnO/Al2O3 (CZA) catalysts, where a part of the Al2O3 (0, 25, 50, 75, or 100%) was substituted by La2O3. Results of catalytic performance tests obtained at atmospheric pressure showed that the addition of La2O3 generally resulted in a decrease of CO2 conversion and in an increase of methanol selectivity. Optimal results were obtained for the CZA-La50 catalyst, which exhibited a 30% higher yield of methanol, compared to the un-promoted sample. This was attributed to the relatively high specific surface area and porosity of this material, the creation of basic sites of moderate strength, which enhance adsorption of CO2 and intermediates that favor hydrogenation steps, and the ability of the catalyst to maintain a large part of the copper in its metallic form under reaction conditions. The reaction mechanism was studied with the use of in situ infrared spectroscopy (DRIFTS). It was found that the reaction proceeded with the intermediate formation of surface formate and methoxy species and that both methanol and CO were mainly produced via a common formate intermediate species. The kinetic behavior of the best performing CZA-La50 catalyst was investigated in the temperature range 190–230 °C as a function of the partial pressures of H2 (0.3–0.9 atm) and CO2 (0.05–0.20 atm), and a kinetic model was developed, which described the measured reaction rates satisfactorily. Full article
(This article belongs to the Special Issue Nanomaterials in Catalysis Applications)
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Article
Enhanced Photocatalytic Activity of Electrospun β-Ga2O3 Nanofibers via In-Situ Si Doping Using Tetraethyl Orthosilicate
Catalysts 2019, 9(12), 1005; https://doi.org/10.3390/catal9121005 - 30 Nov 2019
Cited by 5 | Viewed by 1539
Abstract
β-Ga2O3 has attracted considerable attention as an alternative photocatalyst to replace conventional TiO2 under ultraviolet-C irradiation due to its high reduction and oxidation potential. In this study, to enhance the photocatalytic activity of β-Ga2O3 [...] Read more.
β-Ga2O3 has attracted considerable attention as an alternative photocatalyst to replace conventional TiO2 under ultraviolet-C irradiation due to its high reduction and oxidation potential. In this study, to enhance the photocatalytic activity of β-Ga2O3, nanofibers are formed via the electrospinning method, and Si atoms are subsequently doped. As the Si concentration in the β-Ga2O3 nanofiber increases, the optical bandgap of the β-Ga2O3 nanofibers continuously decreases from 4.5 eV (intrinsic) to 4.0 eV for the Si-doped (2.4 at. %) β-Ga2O3 nanofibers, and accordingly, the photocatalytic activity of the β-Ga2O3 nanofibers is enhanced. This higher photocatalytic performance with Si doping is attributed to the increased doping-induced carriers in the conduction band edges. This differs from the traditional mechanism in which the doping-induced defect sites in the bandgap enhance separation and inhibit the recombination of photon-generated carriers. Full article
(This article belongs to the Special Issue Nanomaterials in Catalysis Applications)
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Article
Oxidative Thermal Sintering and Redispersion of Rh Nanoparticles on Supports with High Oxygen Ion Lability
Catalysts 2019, 9(6), 541; https://doi.org/10.3390/catal9060541 - 17 Jun 2019
Cited by 31 | Viewed by 2357
Abstract
The thermal sintering under oxidative conditions of Rh nanoparticles supported on oxides characterized by very different oxygen storage capacities (OSC) and labilities was studied at 750 and 850 °C. Under sintering conditions, significant particle growth occurred for Rh/γ-Al2O3 (up to [...] Read more.
The thermal sintering under oxidative conditions of Rh nanoparticles supported on oxides characterized by very different oxygen storage capacities (OSC) and labilities was studied at 750 and 850 °C. Under sintering conditions, significant particle growth occurred for Rh/γ-Al2O3 (up to 120% at 850 °C). In striking contrast, Rh/ACZ (alumina–ceria–zirconia) and Rh/CZ (ceria–zirconia) exhibited marked resistance to sintering, and even moderate (ca. −10% at 850 °C) to pronounced (ca. −60% at 850 °C) redispersion of the Rh. A model is proposed based on a double-layer description of metal–support interactions assigned to back-spillover of labile oxygen ions onto the Rh particles, accompanied by trapping of atomic Rh by the resulting surface oxygen vacancies. This model accounts for the observed resistance to sintering and actual redispersion of Rh, consistent with both alternative sintering mechanisms, namely Ostwald ripening (OR) or particle migration and coalescence (PMC). Full article
(This article belongs to the Special Issue Nanomaterials in Catalysis Applications)
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Correction
Correction: Liu, W., et al. Synthesis and Characterization of N‐Doped SiC Powder with Enhanced Photocatalytic and Photoelectrochemical Performance. Catalysts 2020, 10, 769
Catalysts 2020, 10(10), 1155; https://doi.org/10.3390/catal10101155 - 08 Oct 2020
Cited by 1 | Viewed by 568
Abstract
The authors wish to make the following corrections to this paper [1] [...] Full article
(This article belongs to the Special Issue Nanomaterials in Catalysis Applications)
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