Special Issue "Novel Photocatalysts for Environmental and Energy Applications"

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

Deadline for manuscript submissions: closed (10 December 2021) | Viewed by 7727

Special Issue Editors

Prof. Dr. Dionysios (Dion) Demetriou Dionysiou
grade E-Mail Website
Guest Editor
Environmental Engineering and Science Program, Department of Chemical and Environmental Engineering (ChEE), University of Cincinnati, Cincinnati, OH 45221-0012, USA
Interests: advanced oxidation; advanced reduction; nanotechnology; water treatment; water reuse; water quality; (photo)catalysis; environmental catalysis; environmental sensors; emerging contaminants; cyanotoxins
Special Issues, Collections and Topics in MDPI journals
Dr. Sami Rtimi
E-Mail Website
Guest Editor
Swiss Federal Institute of Technology Lausanne (EPFL), 1015 Lausanne, Switzerland
Interests: photocatalysis; supported catalysts; antibacterial; self-cleaning; characterization
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Prof. Dr. Ewa Kowalska
E-Mail Website
Guest Editor
Institute for Catalysis (ICAT), Hokkaido University, N21, W10, Sapporo 001-0026, Japan
Interests: heterogeneous photocatalysis; advanced oxidation processes (AOPs); environmental purification; plasmonic nanoparticles; antimicrobial properties; visible-light-responsive materials
Special Issues, Collections and Topics in MDPI journals
Dr. Changseok Han
E-Mail Website
Guest Editor
Department of Environmental Engineering, INHA University, Incheon 22212, Korea
Interests: advanced oxidation processes; photocatalysis; toxins; contaminants of emerging concern; nutrients recovery; water treatment
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Dr. Marcin Janczarek
E-Mail Website
Guest Editor
Poznan University of Technology, Faculty of Chemical Technology, Institute of Chemical Technology and Engineering, Berdychowo 4, PL-60965 Poznan, Poland
Interests: photocatalysis, nanomaterials, faceted nanoparticles, solar energy, advanced oxidation technologies
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Due to exponential industrialization and rapid population growth, the global energy crisis and environmental pollution have become two of the greatest humanitarian challenges of the 21st century. The utilization of powerful, affordable, and renewable energy sources for energy production and pollutant elimination is considered as the best solution for addressing these critical problems. Therefore, much effort has been devoted toward converting solar energy into an applicable energy medium through various technologies, including photocatalysis, solar cells, and photoelectrochemical cells.

Furthermore, the ever-rising demand for fossil fuels, concomitant with the collateral increase in atmospheric CO2 concentrations, have necessitated the urgent development of carbon management technologies. To this end, much research has been devoted towards the search for new technologies in the reduction of CO2. Moreover, numerous topics within the fields of bioconversion and catalysis/photocatalysis (photothermal catalysis) have also been investigated.

The current environmental and energy issues require the urgent design, preparation, and validation of well-designed photocatalytic materials. Thanks to their ability to use light/sunlight, these catalysts are able to stimulate various reactions and/or produce energy. Mimicking the natural photosynthesis system, Z-scheme photocatalysts, as one example, were reported to present many merits, including improved light harvesting, spatially separated reductive and oxidative active sites, and well-preserved strong redox ability. The first generation of Z-scheme photocatalysts can be summarized in the liquid-phase Z-scheme, and have evolved up to the direct Z-scheme photocatalysts. Many other novel functional and composite catalysts are being developed and tested in various environmental and energy applications. While there are still challenges facing further scalability and the applicability of associated technologies for practical and large-scale implementation, there is clear evidence of progress in the development of new catalysts with improved performance and functionality, as well as understanding of the underlying catalytic and photocatalytic phenomena and their associated mechanisms. However, there are certainly many opportunities in the design of new catalysts with improved performance, tailored functionalities, and use in various existing and new applications.

This Special Issue “Novel Photocatalysts for Environmental and Energy Applications” covers the design, preparation, and characterization of novel photocatalytic materials, as well as their applications in environmental remediation and novel routes for energy production. This Special Issue welcomes contributions on (but not limited to):

  • Photocatalysts for environmental application and energy conversion;
  • Photoactive materials for energy conversion;
  • Z-scheme photocatalysts;
  • Hybrid materials for visible/solar light harvesting;
  • Photocatalysts for water splitting;
  • Functional materials for carbon dioxide capture and conversion;
  • Photocatalytic self-cleaning surfaces;
  • Photocatalysts with antimicrobial properties, including antibiotic resistance;
  • Photocatalytic applications in medical and biomedical fields;
  • Photocatalytic materials for water and wastewater purification and reuse;
  • Photocatalysts for air treatment and industrial gas phase streams;
  • Photocatalytic materials in food preservation;
  • Photocatalytic application in non-conventional environments (i.e., space exploration).

Prof. Dionysios (Dion) Demetriou Dionysiou
Dr. Sami Rtimi
Prof. Ewa Kowalska
Prof. Changseok Han
Dr. Marcin Janczarek
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

  • photocatalytic materials
  • preparation methods
  • mechanistic aspects
  • structure–reactivity
  • energy conversion
  • environmental applications
  • water treatment
  • disinfection, antimicrobial

Published Papers (7 papers)

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Editorial

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Editorial
Novel Photocatalysts for Environmental and Energy Applications
Catalysts 2022, 12(5), 458; https://doi.org/10.3390/catal12050458 - 20 Apr 2022
Viewed by 470
Abstract
Due to exponential industrialization and rapid population growth, the global energy crisis and environmental pollution have become two of the greatest humanitarian challenges of the 21st century [...] Full article
(This article belongs to the Special Issue Novel Photocatalysts for Environmental and Energy Applications)

Research

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Article
Enhanced Photocatalytic Activity of Hierarchical Bi2WO6 Microballs by Modification with Noble Metals
Catalysts 2022, 12(2), 130; https://doi.org/10.3390/catal12020130 - 21 Jan 2022
Cited by 3 | Viewed by 903
Abstract
Visible-responsive photocatalysts for environmental purification and fuel generation are, currently, highly sought after. Among the possible candidates, Bi2WO6 (BWO) has been considered due to its efficient light harvesting, stability, and promising activities. Here, hierarchical BWO microballs have been prepared using [...] Read more.
Visible-responsive photocatalysts for environmental purification and fuel generation are, currently, highly sought after. Among the possible candidates, Bi2WO6 (BWO) has been considered due to its efficient light harvesting, stability, and promising activities. Here, hierarchical BWO microballs have been prepared using a hydrothermal method, and additionally modified with deposits of noble metals (gold, silver, copper, palladium and platinum) by the photodeposition method. The structure, morphology, photoabsorption properties, and surface composition of bare and metal-modified BWO samples were investigated by XRD, SEM, DRS and XPS analyses. The photocatalytic activity was evaluated by the oxidative degradation of model dye (methyl orange (MO)) under UV/vis, and hydrogen generation under vis and/or UV irradiation. It was found that hierarchical morphology is detrimental for high photocatalytic activity in both tested systems, resulting in the improved degradation of MO (ca. 65% during 90 min of UV/vis irradiation), and hydrogen evolution (0.1 and 0.4 μmol h−1 under vis and UV/vis irradiation, respectively). Moreover, the type of noble metal and its properties influence the overall photocatalytic performance. It was found that, under UV/vis irradiation, only platinum accelerates hydrogen evolution, whereas under vis irradiation the activity follows the order: BWO < BWO/Cu < BWO/Ag < BWO/Pt < BWO/Pd < BWO/Au. It was concluded that zero-valent metal is recommended for high vis response, probably due to plasmonic photocatalysis, efficient light harvesting ability, and co-catalytic role. Full article
(This article belongs to the Special Issue Novel Photocatalysts for Environmental and Energy Applications)
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Article
Spectroscopic Analyses of Changes in Photocatalytic and Catalytic Activities of Mn- and Ni-Ion Doped and Base-Treated Reduced Graphene Oxide
Catalysts 2021, 11(8), 990; https://doi.org/10.3390/catal11080990 - 18 Aug 2021
Cited by 1 | Viewed by 653
Abstract
While reduced graphene oxide (rGO) is used widely as a catalyst, its catalytic activity can be improved significantly by modifying it with a metal. In this study, we compared the photocatalytic and catalytic properties of base-treated rGO particles and transition-metal-ion-doped rGO based on [...] Read more.
While reduced graphene oxide (rGO) is used widely as a catalyst, its catalytic activity can be improved significantly by modifying it with a metal. In this study, we compared the photocatalytic and catalytic properties of base-treated rGO particles and transition-metal-ion-doped rGO based on the oxidation reaction of thiophenol and the photocatalytic degradation of 4-chlorophenol. Since the two catalytic activities are related to the changes in the electronic structure of rGO, X-ray photoemission spectroscopy, X-ray absorption spectroscopy, and Raman spectroscopy were performed. When rGO was doped with Mn2+ ions, its catalytic properties improved with respect to both reactions. The changes in the electronic structure of rGO are attributed to the formation of defect structures on the rGO surface via a reaction between the doped Mn2+ ions and oxygen of the rGO surface. Thus, the results show that the doping of rGO with Mn ions in the +2-charge state (stable oxide form: MnO) enhances its catalytic and photocatalytic activities. Hence, this study provides new insights into the use of defect-controlled rGO as a novel catalyst. Full article
(This article belongs to the Special Issue Novel Photocatalysts for Environmental and Energy Applications)
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Article
Effects of Reaction Temperature on the Photocatalytic Activity of TiO2 with Pd and Cu Cocatalysts
Catalysts 2021, 11(8), 966; https://doi.org/10.3390/catal11080966 - 12 Aug 2021
Cited by 7 | Viewed by 894
Abstract
The aim of this study was to investigate the effects of reaction temperature on the photocatalytic activity of TiO2 with Pd and Cu cocatalysts. N2 sorption, transmission electron microscopy and high-resolution transmission electron microscopy were used to characterize the specific surface [...] Read more.
The aim of this study was to investigate the effects of reaction temperature on the photocatalytic activity of TiO2 with Pd and Cu cocatalysts. N2 sorption, transmission electron microscopy and high-resolution transmission electron microscopy were used to characterize the specific surface area, pore volume, pore size, morphology and metal distribution of the catalysts. The photocatalytic destruction of methylene blue under UV light irradiation was used to test its activity. The concentration of methylene blue in water was determined by UV-vis spectrophotometer. Pd/TiO2 catalyst was more active than Cu/TiO2 and TiO2. At 0–50 °C reaction temperature, the activity of TiO2 and Pd/TiO2 increased with an increase of reaction temperature. When the temperature was as high as 70 °C, the reaction rate of TiO2 drop slightly and Pd/TiO2 became less effective. In contrast, Cu/TiO2 was more active at room temperature than the other temperatures. The results indicate that the photocatalytic activity of the catalyst is influenced by the reaction temperature and the type of cocatalyst. When the reaction temperature is higher than 70 °C, the recombination of charge carriers will increase. The temperature range of 50–80 °C is regarded as the ideal temperature for effective photolysis of organic matter. The effects of reaction temperature mainly influence quantum effect, i.e., electron-hole separation and recombination. Full article
(This article belongs to the Special Issue Novel Photocatalysts for Environmental and Energy Applications)
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Article
Towards Computer-Aided Graphene Covered TiO2-Cu/(CuxOy) Composite Design for the Purpose of Photoinduced Hydrogen Evolution
Catalysts 2021, 11(6), 698; https://doi.org/10.3390/catal11060698 - 31 May 2021
Cited by 1 | Viewed by 1092
Abstract
In search a hydrogen source, we synthesized TiO2-Cu-graphene composite photocatalyst for hydrogen evolution. The catalyst is a new and unique material as it consists of copper-decorated TiO2 particles covered tightly in graphene and obtained in a fluidized bed reactor. Both, [...] Read more.
In search a hydrogen source, we synthesized TiO2-Cu-graphene composite photocatalyst for hydrogen evolution. The catalyst is a new and unique material as it consists of copper-decorated TiO2 particles covered tightly in graphene and obtained in a fluidized bed reactor. Both, reduction of copper from Cu(CH3COO) at the surface of TiO2 particles and covering of TiO2-Cu in graphene thin layer by Chemical Vapour Deposition (CVD) were performed subsequently in the flow reactor by manipulating the gas composition. Obtained photocatalysts were tested in regard to hydrogen generation from photo-induced water conversion with methanol as sacrificial agent. The hydrogen generation rate for the most active sample reached 2296.27 µmol H2 h−1 gcat−1. Combining experimental and computational approaches enabled to define the optimum combination of the synthesis parameters resulting in the highest photocatalytic activity for water splitting for green hydrogen production. The results indicate that the major factor affecting hydrogen production is temperature of the TiO2-Cu-graphene composite synthesis which in turn is inversely correlated to photoactivity. Full article
(This article belongs to the Special Issue Novel Photocatalysts for Environmental and Energy Applications)
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Review

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Review
Defective Dopant-Free TiO2 as an Efficient Visible Light-Active Photocatalyst
Catalysts 2021, 11(8), 978; https://doi.org/10.3390/catal11080978 - 16 Aug 2021
Cited by 11 | Viewed by 1100
Abstract
Pristine and modified/doped titania are still some of the most widely investigated photocatalysts due to its high activity, stability, abundance and proper redox properties to carry out various reactions. However, modifiers and/or dopants resulting in visible-light activity might be expensive or work as [...] Read more.
Pristine and modified/doped titania are still some of the most widely investigated photocatalysts due to its high activity, stability, abundance and proper redox properties to carry out various reactions. However, modifiers and/or dopants resulting in visible-light activity might be expensive or work as recombination centers under UV irradiation. It seems that defective titania, known as “self-doped” TiO2, might be the best solution since it can be obtained under mild conditions without the addition of expensive materials and methods. This review discusses various methods of defective titania preparation, characterization of defect types, their localization (surface vs. bulk) and their function, as well as proposed mechanisms of photocatalytic reactions in the presence of self-doped titania. Although many kinds of defective titania samples have already been prepared with different colors, color intensities and defect kinds (mainly Ti3+ and oxygen vacancies), it is difficult to conclude which of them are the most recommended as the preparation conditions and activity testing used by authors differ. Furthermore, activity testing under solar radiation and for dyes does not clarify the mechanism since bare titania can also be excited and sensitized, respectively, in these conditions. In many reports, authors have not considered the possible influence of some impurities originated from the synthesis method (e.g., H, Al, Zn, Cl, F) that could co-participate in the overall mechanism of photocatalytic reactions. Moreover, some reports indicate that defective titania, especially black ones, might decrease activity since the defects might work as recombination centers. Despite some unproven/unclear findings and unanswered questions, there are many well-conducted studies confirmed by both experimental and theoretical studies that defective titania might be a promising material for various photocatalytic reactions under both UV and visible-light irradiation. Based on available literature, it could be proposed that optimal defects’ concentration, the preferential role of surface defects, a higher surface-to-bulk ratio of defects in rutile than in anatase, and the beneficial impact of disordered surface are the most important aspects to be considered during the preparation of defective titania. Full article
(This article belongs to the Special Issue Novel Photocatalysts for Environmental and Energy Applications)
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Review
Recent Progress in Plasmonic Hybrid Photocatalysis for CO2 Photoreduction and C–C Coupling Reactions
Catalysts 2021, 11(2), 155; https://doi.org/10.3390/catal11020155 - 22 Jan 2021
Cited by 4 | Viewed by 1502
Abstract
Plasmonic hybrid nanostructures have been investigated as attractive heterogeneous photocatalysts that can utilize sunlight to produce valuable chemicals. In particular, the efficient photoconversion of CO2 into a stable hydrocarbon with sunlight can be a promising strategy to achieve a sustainable human life [...] Read more.
Plasmonic hybrid nanostructures have been investigated as attractive heterogeneous photocatalysts that can utilize sunlight to produce valuable chemicals. In particular, the efficient photoconversion of CO2 into a stable hydrocarbon with sunlight can be a promising strategy to achieve a sustainable human life on Earth. The next step for hydrocarbons once obtained from CO2 is the carbon–carbon coupling reactions to produce a valuable chemical for energy storage or fine chemicals. For these purposes, plasmonic nanomaterials have been widely investigated as a visible-light-induced photocatalyst to achieve increased efficiency of photochemical reactions with sunlight. In this review, we discuss recent achievements involving plasmonic hybrid photocatalysts that have been investigated for CO and CO2 photoreductions to form multi-carbon products and for C–C coupling reactions, such as the Suzuki–Miyaura coupling reactions. Full article
(This article belongs to the Special Issue Novel Photocatalysts for Environmental and Energy Applications)
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