Special Issue "State-of-the-Art Photocatalytical Technology in North America"

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

Deadline for manuscript submissions: 30 September 2019

Special Issue Editor

Guest Editor
Prof. Dr. Mehrab Mehrvar

Department of Chemical Engineering, Ryerson University, 350 Victoria Street, Toronto, ON, Canada M5 B 2K3, Canada
Website | E-Mail
Phone: 416-979-5000 ext 6555
Interests: photochemical reaction engineering including photocatalysis, UV/hydrogen peroxide, Fenton/photo-Fenton, etc.; integration of advanced oxidation technologies and biological processes for wastewater treatment; effects of climate change on the quality and quantity of groundwater

Special Issue Information

Dear Colleagues,

Recent studies have been devoted to the use of advanced oxidation processes (AOPs) for the destruction of organic materials from wastewater, mainly because AOPs can entirely eradicate organics. Depending on the applications, different AOPs have been studied. Among AOPs, photocatalysis is a promising process of eradicating almost all types of organics in wastewater. Despite all advantages of TiO2, there are two major limitations in its photocatalytic activity, its activation in the ultraviolet range and a high rate of electron-hole recombination, leading to its low efficiency. Therefore, the photocatalytic efficiency depends on how well a photocatalyst can prevent electron-hole pair recombination. There have been many studies on photocatalysis including doping metals and non-metals as well as mixing different photocatalysts. This Special Issue will focus on the latest developments in photocatalysis including photochemical reaction engineering, photoreactor design, photocatalyst development, or combining photocatalysis with other processes to enhance organic degradation in water and wastewater.

This Special Issue strives to provide an overview on state-of-the-art photocatalytical technology in North America.

Prof. Dr. Mehrab Mehrvar
Guest Editor

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 papers will be 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 1600 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

  • Photocatalysis
  • Doping photocatalysts
  • Advanced Oxidation Technologies
  • Photocatalytic Reaction Engineering
  • Photoreactor Design
  • Photocatalytic Efficiency
  • Combined Photocatalysis with other processes
  • Photocatalytic Kinetics

Published Papers (4 papers)

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Research

Open AccessArticle Photocatalytic Degradation of Profenofos and Triazophos Residues in the Chinese Cabbage, Brassica chinensis, Using Ce-Doped TiO2
Catalysts 2019, 9(3), 294; https://doi.org/10.3390/catal9030294
Received: 24 January 2019 / Revised: 14 March 2019 / Accepted: 15 March 2019 / Published: 22 March 2019
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Abstract
Pesticides have revolutionized the modern day of agriculture and substantially reduced crop losses. Synthetic pesticides pose a potential risk to the ecosystem and to the non-target organisms due to their persistency and bioaccumulation in the environment. In recent years, a light-mediated advanced oxidation [...] Read more.
Pesticides have revolutionized the modern day of agriculture and substantially reduced crop losses. Synthetic pesticides pose a potential risk to the ecosystem and to the non-target organisms due to their persistency and bioaccumulation in the environment. In recent years, a light-mediated advanced oxidation processes (AOPs) has been adopted to resolve pesticide residue issues in the field. Among the current available semiconductors, titanium dioxide (TiO2) is one of the most promising photocatalysts. In this study, we investigated the photocatalytic degradation of profenofos and triazophos residues in Chinese cabbage, Brassica chinensis, using a Cerium-doped nano semiconductor TiO2 (TiO2/Ce) under the field conditions. The results showed that the degradation efficiency of these organophosphate pesticides in B. chinensis was significantly enhanced in the presence of TiO2/Ce. Specifically, the reactive oxygen species (ROS) contents were significantly increased in B. chinensis with TiO2/Ce treatment, accelerating the degradation of profenofos and triazophos. Ultra-performance liquid chromatography–mass spectroscopy (UPLC-MS) analysis detected 4-bromo-2-chlorophenol and 1-phenyl-3-hydroxy-1,2,4-triazole, the major photodegradation byproducts of profenofos and triazophos, respectively. To better understand the relationship between photodegradation and the molecular structure of these organophosphate pesticides, we investigated the spatial configuration, the bond length and Mulliken atomic charge using quantum chemistry. Ab initio analysis suggests that the bonds connected by P atom of profenofos/triazophos are the initiation cleavage site for photocatalytic degradation in B. chinensis. Full article
(This article belongs to the Special Issue State-of-the-Art Photocatalytical Technology in North America)
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Open AccessArticle An Effective Approach to Improve the Photocatalytic Activity of Graphitic Carbon Nitride via Hydroxyl Surface Modification
Catalysts 2019, 9(1), 17; https://doi.org/10.3390/catal9010017
Received: 25 November 2018 / Revised: 21 December 2018 / Accepted: 24 December 2018 / Published: 28 December 2018
Cited by 1 | PDF Full-text (3507 KB) | HTML Full-text | XML Full-text
Abstract
In this work, we have developed a hydrothermal method to modify g-C3N4 with hydroxyl surface modification. Modified g-C3N4 has exhibited higher photocatalytic activity in the removal of phenolic compounds under visible light. The improvement may be due [...] Read more.
In this work, we have developed a hydrothermal method to modify g-C3N4 with hydroxyl surface modification. Modified g-C3N4 has exhibited higher photocatalytic activity in the removal of phenolic compounds under visible light. The improvement may be due to the following merits: (1) Tuning of the hydrophobic surface of g-C3N4 to be hydrophilic; (2) improved adsorption energy, and (3) narrowed band gap for g-C3N4 after hydroxyl surface modification. This method is easy-to-operate, very effective in adding hydroxyl groups on the surface of C3N4, and may be extended to other systems to promote their photocatalytic activities in water treatment. Full article
(This article belongs to the Special Issue State-of-the-Art Photocatalytical Technology in North America)
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Graphical abstract

Open AccessArticle Photocatalytic Treatment of An Actual Confectionery Wastewater Using Ag/TiO2/Fe2O3: Optimization of Photocatalytic Reactions Using Surface Response Methodology
Catalysts 2018, 8(10), 409; https://doi.org/10.3390/catal8100409
Received: 15 August 2018 / Revised: 15 September 2018 / Accepted: 17 September 2018 / Published: 21 September 2018
Cited by 2 | PDF Full-text (5406 KB) | HTML Full-text | XML Full-text
Abstract
Titanium dioxide (TiO2) photocatalysis is one of the most commonly studied advanced oxidation processes (AOPs) for the mineralization of deleterious and recalcitrant compounds present in wastewater as it is stable, inexpensive, and effective. Out of all, doping with metal and non-metals, [...] Read more.
Titanium dioxide (TiO2) photocatalysis is one of the most commonly studied advanced oxidation processes (AOPs) for the mineralization of deleterious and recalcitrant compounds present in wastewater as it is stable, inexpensive, and effective. Out of all, doping with metal and non-metals, and the heterojunction with another semiconductor were proven to be efficient methods in enhancing the degradation of organic pollutants under ultraviolet (UV) and visible light. However, complex degradation processes in the treatment of an actual wastewater are difficult to model and optimize. In the present study, the application of a modified photocatalyst, Ag/TiO2/Fe2O3, for the degradation of an actual confectionery wastewater was investigated. Factorial studies and statistical design of experiments using the Box-Behnken method along with response surface methodology (RSM) were employed to identify the individual and cross-factor effects of independent parameters, including light wavelength (nm), photocatalyst concentration (g/L), initial pH, and initial total organic carbon (TOC) concentration (g/L). The maximum TOC removal at optimum conditions of light wavelength (254 nm), pH (4.68), photocatalyst dosage (480 mg/L), and initial TOC concentration (11,126.5 mg/L) was determined through the numerical optimization method (9.78%) and validated with experimental data (9.42%). Finally, the first-order rate constant with respect to TOC was found to be 0.0005 min−1 with a residual value of 0.998. Full article
(This article belongs to the Special Issue State-of-the-Art Photocatalytical Technology in North America)
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Open AccessArticle Flame-Sprayed Pure and Ce-Doped TiO2 Photocatalysts
Catalysts 2018, 8(9), 342; https://doi.org/10.3390/catal8090342
Received: 18 July 2018 / Revised: 15 August 2018 / Accepted: 17 August 2018 / Published: 22 August 2018
Cited by 2 | PDF Full-text (2796 KB) | HTML Full-text | XML Full-text
Abstract
Pure and Ce-doped TiO2 nanoparticles were successfully synthesized in one step by means of the scalable flame spray pyrolysis (FSP) process. Complete structural and chemical characterization of these materials revealed that the majority of the nanoparticles are crystalline and spherical, ranging from [...] Read more.
Pure and Ce-doped TiO2 nanoparticles were successfully synthesized in one step by means of the scalable flame spray pyrolysis (FSP) process. Complete structural and chemical characterization of these materials revealed that the majority of the nanoparticles are crystalline and spherical, ranging from 5 to 45 nm in diameter. The band gap of TiO2 was reduced by doping with Ce from 2.43 to 3.06 eV and the Ce–TiO2 nanoparticles exhibit a strong photoelectrical response to visible light illumination. Ce–TiO2 nanoparticles obtained with this scalable method are trivially scalable to industrial level manufacturing, granting and enabling additional approaches for the actual application of ceramic oxide nanomaterials to combat challenges such as environmental cleanup and energy production from the visible part of solar inputs. Full article
(This article belongs to the Special Issue State-of-the-Art Photocatalytical Technology in North America)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Exfoliated Molybdenum Disulfide with Metal-Organic Framework for Use in Photocatalytic Hydrogen Evolution
Authors: Ren Ren and Junhong Chen*
Affiliation: University of Wisconsin-Milwaukee, [email protected]
Abstract: Metal-organic frameworks (MOFs) have attracted substantial research attention owing to their tunable pore size, high pore volume, high specific surface area, and highly ordered crystalline porous networks. Previous studies have mostly focused on sensing, drug delivery, batteries, and selective catalysis; however, their application as photocatalysts has not been thoroughly reported. It is well known that bulk MoS2 is unsuitable for photocatalytic applications due to the insufficient reduction and oxidation ability for the photocatalysis. However, exfoliated MoS2 exhibits a direct band gap of 2.8 eV resulting from quantum confinement, which enables it to possess suitable band positions and good visible-light absorption ability. As a result, it is considered to be a promising candidate for photocatalytic applications. Encapsulating exfoliated MoS2 into MOF (MoS2@MOF) can lead to enhanced absorption in the visible light range compared with pure MOF and the highest hydrogen production rate could reach 68.4 μmol h-1g-1, which is much higher than that on pure MOF. With suitable band structure and improved light-harvesting ability, exfoliated MoS2@MOF can be a promising photocatalyst for hydrogen production.
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