Search query: Photocatalytic

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abstract: 2.3. Evaluation of Photocatalytic Water Splitting 6507 2.3.1. Photocatalytic Activity 6507 2.3.2. Photocatalytic Stability 6507 3. UV Active Photocatalysts for Water Splitting 6507 3.1. d0 Metal Oxide Photocatalyts 6507 3.1.1. Ti Zr Based Oxides 6507 3.1.2. Nb Ta Based Oxides 6514 3.1.3. W Mo Based Oxides 6517 3.1.4. Other d0 Metal Oxides 6518 3.2. d10 Metal Oxide Photocatalyts 6518 3.3. f0 Metal Oxide Photocatalysts 6518 3.4. Nonoxide Photocatalysts 6518 4. Approaches to Modifying the Electronic Band Structure for Visible Light Harvesting 6519
author_names: Xiaobo Chen

Shaohua Shen

Liejin Guo

Samuel S Mao
title: Semiconductor based photocatalytic hydrogen generation.
venue: Chemical reviews
year: 2010

abstract: Photocatalytic and photoelectrochemical water splitting under irradiation by sunlight has received much attention for production of renewable hydrogen from water on a large scale. Many challenges still remain in improving energy conversion efficiency, such as utilizing longer wavelength photons for hydrogen production, enhancing the reaction efficiency at any given wavelength, and increasing the lifetime of the semiconductor materials. This introductory review covers the fundamental aspects of photocatalytic and photoelectrochemical water splitting. Controlling the semiconducting properties of photocatalysts and photoelectrode materials is the primary concern in developing materials for solar water splitting, because they determine how much photoexcitation occurs in a semiconductor under solar illumination and how many photoexcited carriers reach the surface where water splitting takes place. Given a specific semiconductor material, surface modifications are important not only to activate the semiconductor for water splitting but also to facilitate charge separation and to upgrade the stability of the material under photoexcitation. In addition, reducing resistance loss and forming p n junction have a significant impact on the efficiency of photoelectrochemical water splitting. Correct evaluation of the photocatalytic and photoelectrochemical activity for water splitting is becoming more important in enabling an accurate comparison of a number of studies based on different systems. In the latter part, recent advances in the water splitting reaction under visible light will be presented with a focus on non oxide semiconductor materials to give an overview of the various problems and solutions.
author_names: Takashi Hisatomi

Jun Kubota

Kazunari Domen
title: Recent advances in semiconductors for photocatalytic and photoelectrochemical water splitting.
venue: Chemical Society reviews
year: 2014

abstract: Abstract Herein, ZnO/CdS hierarchical composite was prepared through a hydrothermal and chemical bath deposition (CBD) process. Its photocatalytic H2 production performance was tested. Mass ratio of CdS acted a pivotal part in light absorption and photocatalytic properties. Noticeably, promoted photocatalytic H2 production activity of 4134 mmol g 1 h 1 was achieved by the sample with optimal CdS content. Significantly, the photoluminescence (PL) detection of hydroxyl radicals, as well as the in situ XPS measurements was selected to verify the direct Z scheme charge migration mechanism. This mechanism endowed the composite with strong capability for hydrogen evolution and elucidated the improved photocatalytic performance. The improvement of photocatalytic activity was due to hierarchical structure, extended visible light response and direct Z scheme mechanism. This work will give an innovative vision in constructing direct Z scheme photocatalytic system with great photocatalytic H2 production activity.
author_names: Sheng Wang

Bicheng Zhu

Mingjin Liu

Liu Yang Zhang

Jiaguo Yu

Minghua Zhou
title: Direct Z scheme ZnO/CdS hierarchical photocatalyst for enhanced photocatalytic H2 production activity
venue: Applied Catalysis B: Environmental
year: 2019

abstract: Abstract The photocatalytic performance of BiVO4 is restricted via the fast recombination of photogenerated carriers and low visible light absorption. Fabricating of CuS/BiVO4 (0 4 0) binary heterogeneous photocatalysts by in suit growing of CuS on the surface of BiVO4 can enhance the absorption range of visible light and the separation of photogenerated carriers. Simultaneously, CuS/BiVO4 heterogeneous can provide large surface area and more active sites. The photocatalytic activity of CuS/BiVO4 composites for Ciprofloxacin (CIP) removal was examined under visible light irradiation. The optimal mass ratio of CuS to BiVO4 was determined to be 7% and the first order kinetic constant of CIP degradation over 7% CuS/BiVO4 (0.02151 min 1) was 2.59 and 16.54 times of pristine BiVO4 and CuS, respectively. The improved photodegradation efficiency is attributed to the effective separation of photogenerated carriers via formation of p n heterojunction. The high photostability of as prepared CuS/BiVO4 heterojunction photocatalysts was explored by four successive cycling experiments. The detailed mechanism for improved photocatalytic performance was discussed and the possible degradation pathway of CIP was measured by Liquid Chromatography Mass/Mass Spectrometry. The trapping experiments and electron spin resonance (ESR) spin trapping tests confirm that holes are main active species in photocatalytic degradation of CIP.
author_names: Cui Lai

Mingming Zhang

Bisheng Li

Danlian Huang

Guangming Zeng

Lei Qin

Xigui Liu

Huan Yi

Min Cheng

Ling Li

Zhang Chen

Liang Chen
title: Fabrication of CuS/BiVO4 (0 4 0) binary heterojunction photocatalysts with enhanced photocatalytic activity for Ciprofloxacin degradation and mechanism insight
venue: Chemical Engineering Journal
year: 2019

abstract: Abstract Water splitting for hydrogen production under light irradiation is an ideal system to provide renewable energy sources and to reduce global warming effects. Even though significant efforts have been devoted to fabricate advanced nanocomposite materials, the main challenge persists, which is lower efficiency and selectivity towards H2 evolution under solar energy. In this review, recent developments in photo catalysts, fabrication of novel heterojunction constructions and factors influencing the photocatalytic process for dynamic H2 production have been discussed. In the mainstream, recent developments in TiO2 and g C3N4 based photo catalysts and their potential for H2 production are extensively studied. The improvements have been classified as strategies to improve different factors of photocatalytic water splitting such as Z scheme systems and influence of operating parameters such as band gap, morphology, temperature, light intensity, oxygen vacancies, pH, and sacrificial reagents. Moreover, thermodynamics for selective photocatalytic H2 production are critically discussed. The advances in photo reactors and their role to provide more light distribution and surface area contact between catalyst and light were systematically described. By applying the optimum operating parameters and new engineering approach on photoreactor, the efficiency of semiconductor photocatalysts for H2 production can be enhanced. The future research and perspectives for photocatalytic water splitting were also suggested.
author_names: Nur Fajrina

Muhammad Tahir
title: A critical review in strategies to improve photocatalytic water splitting towards hydrogen production
year: 2019

abstract: In recent years, semiconductor photocatalytic process has shown a great potential as a low cost, environmental friendly and sustainable treatment technology to align with the "zero" waste scheme in the water/wastewater industry. The ability of this advanced oxidation technology has been widely demonstrated to remove persistent organic compounds and microorganisms in water. At present, the main technical barriers that impede its commercialisation remained on the post recovery of the catalyst particles after water treatment. This paper reviews the recent R&D progresses of engineered photocatalysts, photoreactor systems, and the process optimizations and modellings of the photooxidation processes for water treatment. A number of potential and commercial photocatalytic reactor configurations are discussed, in particular the photocatalytic membrane reactors. The effects of key photoreactor operation parameters and water quality on the photo process performances in terms of the mineralization and disinfection are assessed. For the first time, we describe how to utilize a multi variables optimization approach to determine the optimum operation parameters so as to enhance process performance and photooxidation efficiency. Both photomineralization and photo disinfection kinetics and their modellings associated with the photocatalytic water treatment process are detailed. A brief discussion on the life cycle assessment for retrofitting the photocatalytic technology as an alternative waste treatment process is presented. This paper will deliver a scientific and technical overview and useful information to scientists and engineers who work in this field.
author_names: Meng Nan Chong

Bo Jin

Christopher W K Chow

Christopher P Saint
title: Recent developments in photocatalytic water treatment technology: a review.
venue: Water research
year: 2010

abstract: Abstract The development of efficient photocatalysts for the production of hydrogen peroxide (H2O2) is a promising strategy to realize solar to chemical energy conversion. Graphitic carbon nitride (g C3N4) presents giant potential for photocatalytic H2O2 production, but the sluggish charge separation depresses its photocatalytic performance. Herein, an interfacial Schottky junction composed of Ti3C2 nanosheets and porous g C3N4 nanosheets (TC/pCN) is constructed by a facile electrostatic self assembly route to significantly boost the spatial charge separation to promote the activation of molecular oxygen for H2O2 production. As the optimal sample, TC/pCN 2 possesses the highest H2O2 production rate (2.20 mmol L 1 min 1) under visible light irradiation (l 420 nm) which is about 2.1 times than that of the porous g C3N4. The results of superoxide radical detection and rotating disk electrode measurement suggest that the two step single electron reduction of oxygen is the predominant reaction step during this photocatalytic H2O2 production process. The enhanced photocatalytic performance is ascribed to the formation of Schottky junction and subsequent built in electric field at their interface, which accelerate the spatial charge separation and restrain the charge recombination. This work provides an in depth understanding of the mechanism of photocatalytic H2O2 production, and gives ideas for the design of highly active materials for photocatalytic H2O2 production.
author_names: Yongxiang Yang

Zhuotong Zeng

Guangming Zeng

Danlian Huang

Rong Xiao

Chen Zhang

Chengyun Zhou

Weiping Xiong

Wenjun Wang

Min Cheng

Wen-jing Xue

Hai Guo

Xiang Tang

Donghui He
title: Ti3C2 Mxene/porous g C3N4 interfacial Schottky junction for boosting spatial charge separation in photocatalytic H2O2 production
year: 2019

abstract: Semiconductor photocatalysis has received much attention as a potential solution to the worldwide energy shortage and for counteracting environmental degradation. This article reviews state of the art research activities in the field, focusing on the scientific and technological possibilities offered by photocatalytic materials. We begin with a survey of efforts to explore suitable materials and to optimize their energy band configurations for specific applications. We then examine the design and fabrication of advanced photocatalytic materials in the framework of nanotechnology. Many of the most recent advances in photocatalysis have been realized by selective control of the morphology of nanomaterials or by utilizing the collective properties of nano assembly systems. Finally, we discuss the current theoretical understanding of key aspects of photocatalytic materials. This review also highlights crucial issues that should be addressed in future research activities.
author_names: Hua Tong

Shuxin Ouyang

Yingpu Bi

Naoto Umezawa

Mitsutake Oshikiri

Jinhua Ye
title: Nano photocatalytic materials: possibilities and challenges.
venue: Advanced materials
year: 2012

abstract: Abstract The construction of heterostructures is regarded as an excellent strategy to achieve efficient charge separation and improved photocatalytic activity. Herein, a series of Bi2MoO6/ZnO hierarchical heterostructured photocatalysts were synthesized by a solvothermal method. The morphology of Bi2MoO6 grown on the surface of ZnO nanorods could be controlled by adjusting the experimental conditions. The synthesized samples were characterized by various analytical techniques and their photocatalytic performance was evaluated by photocatalytic reduction of Cr(VI) under visible light irradiation. Compared with those of pure Bi2MoO6 and ZnO, the Bi2MoO6/ZnO composites showed higher photocatalytic activity towards the reduction of Cr(VI) The enhanced photocatalytic activity was mainly attributed to the formation of a heterojunction between Bi2MoO6 and ZnO, which effectively facilitated the separation and transfer of electrons and holes. In addition, the Bi2MoO6/ZnO photocatalysts maintained good stability after three cycles of Cr(VI) photoreduction. A possible photocatalytic mechanism of the as synthesized composites was proposed.
author_names: Guping Zhang

Dongyun Chen

Najun Li

Qingfeng Xu

Hua Li

Jinghui He

Jianmei Lu
title: Fabrication of Bi2MoO6/ZnO hierarchical heterostructures with enhanced visible light photocatalytic activity
venue: Applied Catalysis B: Environmental
year: 2019

abstract: Ever increasing fossil fuel combustion along with massive CO2 emissions has aroused a global energy crisis and climate change. Photocatalytic CO2 reduction represents a promising strategy for clean, cost effective, and environmentally friendly conversion of CO2 into hydrocarbon fuels by utilizing solar energy. This strategy combines the reductive half reaction of CO2 conversion with an oxidative half reaction, e.g. H2 O oxidation, to create a carbon neutral cycle, presenting a viable solution to global energy and environmental problems. There are three pivotal processes in photocatalytic CO2 conversion: (i) solar light absorption, (ii) charge separation/migration, and (iii) catalytic CO2 reduction and H2 O oxidation. While significant progress is made in optimizing the first two processes, much less research is conducted toward enhancing the efficiency of the third step, which requires the presence of cocatalysts. In general, cocatalysts play four important roles: (i) boosting charge separation/transfer, (ii) improving the activity and selectivity of CO2 reduction, (iii) enhancing the stability of photocatalysts, and (iv) suppressing side or back reactions. Herein, for the first time, all the developed CO2 reduction cocatalysts for semiconductor based photocatalytic CO2 conversion are summarized, and their functions and mechanisms are discussed. Finally, perspectives in this emerging area are provided.
author_names: Jingrun Ran

Mietek Jaroniec

Shizhang Qiao
title: Cocatalysts in Semiconductor based Photocatalytic CO2 Reduction: Achievements, Challenges, and Opportunities.
venue: Advanced materials
year: 2018