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Catalysts
Special Issues
Role of Defects and Disorder in Catalysis
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Role of Defects and Disorder in Catalysis

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

Deadline for manuscript submissions: closed (15 August 2022) | Viewed by 10236

Special Issue Editors

Dr. Kulbir Ghuman

E-Mail Website
Guest Editor
Institut National de la Recherché, Centre Énergie Matériaux Télécommunications, 1650 Boul. Lionel-Boulet, Varennes, QC J3X 1S2, Canada
Interests: computational materials design; sustainable energy; heterogeneous catalysis; solid oxide fuel cells; quantum and classical mechanics simulations; surfaces and interfaces; nanomaterials; disordered materials; point defects; dislocations; grain boundaries; CO2 reduction; water splitting; ammonia synthesis
Dr. Aleksandar Staykov

E-Mail Website
Guest Editor
International Institute for Carbon Neutral Energy Research, Kyushu University, Fukuoka, Japan
Interests: computational material design; solid oxides; nanotechnology; nanoelectronics

Special Issue Information

Dear Colleagues, 

The functionality of catalysts used in chemical reactions is critically determined by the properties of defects and disorder present in them. Often, the catalysts used in chemical processes either completely lack a long-range order and have the same key features as crystalline materials only at medium or short length scales, or they contain a partial low symmetry environment, due to at least one of the following imperfections: (a) 0D (dimension) or point defects (such as vacancies, interstitials, etc.); (b) 1D or linear defects (such as dislocations, disclinations, etc.); (c) 2D or planar defects (such as grain boundaries (GBs), surfaces, etc.); (d) 3D or extended defects (such as pores, cracks, etc.). These defected and disordered regions in materials, if well utilized, can provide sustainable solutions to alleviate the energy crisis of today’s world by bringing innovation in designing sustainable technologies. The potential topics of this Special Issue thus include (but are not limited to):

  • Disordered/amorphous materials for catalysis;
  • Role of point, linear, planar, and extended defects in catalysis;
  • Designing sustainable catalysts for CO2 reduction and conversion, CO2 capture, NH3 synthesis, H2O splitting, etc.;
  • Role of defects and disorder in electrochemical, photochemical, photothermal, and thermochemical catalysis.

Dr. Kulbir Ghuman
Dr. Aleksandar Staykov
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 2700 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

  • disorder and defects
  • photo/electro/thermal catalysis
  • modeling and simulations
  • CO2 capture and conversion
  • sustainable fuels and chemicals
  • fuel cell catalysis
  • physical chemistry
  • inorganic chemistry
  • material science
  • energy materials

Published Papers (4 papers)

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Research

20 pages, 12135 KiB  
Article
Facile Fabrication of Oxygen-Defective ZnO Nanoplates for Enhanced Photocatalytic Degradation of Methylene Blue and In Vitro Antibacterial Activity
by Sujeong Kim, Namgyu Son, Sun-Min Park, Chul-Tae Lee, Sadanand Pandey and Misook Kang
Catalysts 2023, 13(3), 567; https://doi.org/10.3390/catal13030567 - 10 Mar 2023
Cited by 8 | Viewed by 1282
Abstract
In this study, we examined whether catalysts with many defects have excellent photoactivity. We prepared ZnO nanoplates with varying degrees of defects in a short time of 4 h by varying the crystal growth temperature at 50, 100, 150, and 200 °C under [...] Read more.
In this study, we examined whether catalysts with many defects have excellent photoactivity. We prepared ZnO nanoplates with varying degrees of defects in a short time of 4 h by varying the crystal growth temperature at 50, 100, 150, and 200 °C under a strong alkali NaOH atmosphere of 4.0 M. During high-temperature preparation of ZnO, crystal defects were reduced and crystallinity was further increased. In crystallized systems over 100 °C, rhombic nanoplates were used to control particle shape and induce growth in only two axes. The PL, Raman, and XPS analyses confirmed the presence of strong oxygen vacancies in all ZnO nanoplates, and the vacancies decreased with increasing crystallization temperatures. Methylene blue (MB) dye was initially fixed at 50 mg/L with a peak decrease in absorption at 600–700 nm, confirming its decomposition over time. For the 5 h reaction, the MB removal concentration follows the following order: ZnO-50 < ZnO-100 < ZnO-150 < ZnO-200. The study confirms that ZnO-200 nanoplates with fewer oxygen vacancies decompose MB more quickly. ZnO-200 nanoplates synthesized at 200 °C provided the best sterilization performance when tested against gram-positives and gram-negatives, Escherichia coli and Staphylococcus aureus, respectively. ZnO-200 nanoplates after 3 h showed a high sterilization performance of 96.95% (86.67% in a dark room) for staphylococcus aureus and 95.82% (74.66% in a dark room) for Escherichia coli when irradiated with light. Particularly noteworthy in this study is that ·OH and ·O2− radicals are generated more strongly in ZnO-200 than in ZnO-50 nanoplates. These results show that too-strong oxygen vacancies rather inhibit the antibacterial performance, and that the virtue of moderation also exists in the catalytic activity. Full article
(This article belongs to the Special Issue Role of Defects and Disorder in Catalysis)
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18 pages, 5758 KiB  
Article
Is Black Titania a Promising Photocatalyst?
by Marcin Janczarek, Maya Endo-Kimura, Kunlei Wang, Zhishun Wei, Md Mahbub A. Akanda, Agata Markowska-Szczupak, Bunsho Ohtani and Ewa Kowalska
Catalysts 2022, 12(11), 1320; https://doi.org/10.3390/catal12111320 - 27 Oct 2022
Cited by 4 | Viewed by 2781
Abstract
Five different (commercial and self-synthesized) titania samples were mixed with NaBH4 and then heated to obtain black titania samples. The change in synthesis conditions resulted in the preparation of nine different photocatalysts, most of which were black in color. The photocatalysts were [...] Read more.
Five different (commercial and self-synthesized) titania samples were mixed with NaBH4 and then heated to obtain black titania samples. The change in synthesis conditions resulted in the preparation of nine different photocatalysts, most of which were black in color. The photocatalysts were characterized by various methods, including X-ray diffraction (XRD), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), scanning transmission electron microscopy (STEM), photoacoustic and reverse-double beam photoacoustic spectroscopy (PAS/RDB-PAS). The photocatalytic activity was tested for oxidative decomposition of acetic acid, methanol dehydrogenation, phenol degradation and bacteria inactivation (Escherichia coli) under different conditions, i.e., irradiation with UV, vis, and NIR, and in the dark. It was found that the properties of the obtained samples depended on the features of the original titania materials. A shift in XRD peaks was observed only in the case of the commercial titania samples, indicating self-doping, whereas faceted anatase samples (self-synthesized) showed high resistance towards bulk modification. Independent of the type and degree of modification, all modified samples exhibited much worse activity under UV irradiation than original titania photocatalysts both under aerobic and anaerobic conditions. It is proposed that the strong reduction conditions during the samples’ preparation resulted in the partial destruction of the titania surface, as evidenced by both microscopic observation and crystallographic data (an increase in amorphous content), and thus the formation of deep electron traps (bulk defects as oxygen vacancies) increasing the charge carriers’ recombination. Under vis irradiation, a slight increase in photocatalytic performance (phenol degradation) was obtained for only four samples, while two samples also exhibited slight activity under NIR. In the case of bacteria inactivation, some modified samples exhibited higher activity under both vis and NIR than respective pristine titania, which could be useful for disinfection, cancer treatment and other purposes. However, considering the overall performance of the black titania samples in this study, it is difficult to recommend them for broad environmental applications. Full article
(This article belongs to the Special Issue Role of Defects and Disorder in Catalysis)
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13 pages, 4230 KiB  
Article
Cu Modified TiO2 Catalyst for Electrochemical Reduction of Carbon Dioxide to Methane
by Akihiko Anzai, Ming-Han Liu, Kenjiro Ura, Tomohiro G. Noguchi, Akina Yoshizawa, Kenichi Kato, Takeharu Sugiyama and Miho Yamauchi
Catalysts 2022, 12(5), 478; https://doi.org/10.3390/catal12050478 - 23 Apr 2022
Cited by 9 | Viewed by 2890
Abstract
Electrochemical reduction of CO2 (ECO2R) is gaining attention as a promising approach to store excess or intermittent electricity generated from renewable energies in the form of valuable chemicals such as CO, HCOOH, CH4, and so on. Selective ECO [...] Read more.
Electrochemical reduction of CO2 (ECO2R) is gaining attention as a promising approach to store excess or intermittent electricity generated from renewable energies in the form of valuable chemicals such as CO, HCOOH, CH4, and so on. Selective ECO2R to CH4 is a challenging target because the rate-determining step of CH4 formation, namely CO* protonation, competes with hydrogen evolution reaction and the C–C coupling toward the production of longer-chain chemicals. Herein, a Cu-TiO2 composite catalyst consisting of CuOx clusters or Cu nanoparticles (CuNPs), which are isolated on the TiO2 grain surface, was synthesized using a one-pot solvothermal method and subsequent thermal treatment. The Cu-TiO2 catalyst exhibited high selectivity for CH4, and the ratio of FE for CH4 to total FE for all products in ECO2R reached 70%. Full article
(This article belongs to the Special Issue Role of Defects and Disorder in Catalysis)
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12 pages, 2135 KiB  
Article
Uncovering the Mechanism of the Hydrogen Poisoning on Ru Nanoparticles via Density Functional Theory Calculations
by David S. Rivera Rocabado, Mika Aizawa, Tomohiro G. Noguchi, Miho Yamauchi and Takayoshi Ishimoto
Catalysts 2022, 12(3), 331; https://doi.org/10.3390/catal12030331 - 14 Mar 2022
Cited by 7 | Viewed by 2472
Abstract
Although hydrogen plays a crucial role in ammonia synthesis, very little is known about its poisoning of Ru catalysts. In this study, density functional theory calculations of H2 and N2 dissociations, and H atom binding on Ru153 were performed to [...] Read more.
Although hydrogen plays a crucial role in ammonia synthesis, very little is known about its poisoning of Ru catalysts. In this study, density functional theory calculations of H2 and N2 dissociations, and H atom binding on Ru153 were performed to provide a fundamental understanding of hydrogen poisoning. Because of the kinetic dominance of the H2 dissociation over N2 (vertically or horizontally adsorbed) splitting, the dissociated H atoms block the active sites required for horizontal (less energetically demanding dissociation) N2 adsorption to occur either from the gas phase or after its geometrical transformation from being adsorbed vertically. Additionally, the dissociated H atoms withdraw electrons from the surface, which reduces the ability of the neighboring Ru atoms to donate electrons for N2 activation, hindering its dissociation and suppressing ammonia synthesis. Full article
(This article belongs to the Special Issue Role of Defects and Disorder in Catalysis)
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