Search query: photocatalytic water splitting

Related papers:

abstract: Overall water splitting, evolving hydrogen and oxygen in a 2:1 stoichiometric ratio, using particulate photocatalysts is a potential means of achieving scalable and economically viable solar hydrogen production. To obtain high solar energy conversion efficiency, the quantum efficiency of the photocatalytic reaction must be increased over a wide range of wavelengths and semiconductors with narrow bandgaps need to be designed. However, the quantum efficiency associated with overall water splitting using existing photocatalysts is typically lower than ten per cent 1 2 Thus, whether a particulate photocatalyst can enable a quantum efficiency of 100 per cent for the greatly endergonic water splitting reaction remains an open question. Here we demonstrate overall water splitting at an external quantum efficiency of up to 96 per cent at wavelengths between 350 and 360 nanometres, which is equivalent to an internal quantum efficiency of almost unity, using a modified aluminium doped strontium titanate (SrTiO 3 :Al) photocatalyst 3 4 By selectively photodepositing the cocatalysts Rh/Cr 2 O 3 (ref. 5 and CoOOH (refs. 3 6 for the hydrogen and oxygen evolution reactions, respectively, on different crystal facets of the semiconductor particles using anisotropic charge transport, the hydrogen and oxygen evolution reactions could be promoted separately. This enabled multiple consecutive forward charge transfers without backward charge transfer, reaching the upper limit of quantum efficiency for overall water splitting. Our work demonstrates the feasibility of overall water splitting free from charge recombination losses and introduces an ideal cocatalyst/photocatalyst structure for efficient water splitting. Water splitting with an internal quantum efficiency of almost unity is achieved using a modified semiconductor photocatalyst that selectively promotes the hydrogen and oxygen evolution reactions on separate crystal facets.
author_names: Tsuyoshi Takata

Junzhe Jiang

Yoshihisa Sakata

Mamiko Nakabayashi

Naoya Shibata

Vikas Nandal

Kazuhiko Seki

Takashi Hisatomi

Kazunari Domen
title: Photocatalytic water splitting with a quantum efficiency of almost unity
venue: Nature
year: 2020

abstract: Abstract In this work, we investigate the electronic and optical properties of monolayer GeSe and the possibility of enhancement the photocatalytic activities for the water splitting of monolayer GeSe through strain engineering using first principles calculations. Our calculations indicate that monolayer GeSe is a semiconductor with a moderate indirect gap of 1.13 eV at equilibrium and we can control its band gap by biaxial strain. In the presence of biaxial strain e b the semiconductor metal phase transition happens at large compressive strain of 10 and the indirect direct gap transition occurs at e b 4 The optical spectrum of monolayer GeSe are highly anisotropic and biaxial strain can increase the absorption coefficient of monolayer GeSe up to about 6 x 10 5 cm 1. Our calculations demonstrate that monolayer GeSe possesses photocatalytic properties for water splitting at e b 5 and we can enhance its photocatalytic activity by strain.
author_names: Tuan V Vu

Nguyen Thanh Binh

D M Hoat

Nguyen Van Hieu

Nguyen Tuan Anh

Chuong Van Nguyen

Huynh V Phuc

Hamad Rahman Jappor

Mohammed M Obeid

Nguyen Ngoc Hieu
title: Strain tunable electronic and optical properties of monolayer GeSe: Promising for photocatalytic water splitting applications
year: 2020

abstract: Nano sized TiO2 photocatalytic water splitting technology has great potential for low cost, environmentally friendly solar hydrogen production to support the future hydrogen economy. Presently, the solar to hydrogen energy conversion efficiency is too low for the technology to be economically sound. The main barriers are the rapid recombination of photo generated electron/hole pairs as well as backward reaction and the poor activation of TiO2 by visible light. In response to these deficiencies, many investigators have been conducting research with an emphasis on effective remediation methods. Some investigators studied the effects of addition of sacrificial reagents and carbonate salts to prohibit rapid recombination of electron/hole pairs and backward reactions. Other research focused on the enhancement of photocatalysis by modification of TiO2 by means of metal loading, metal ion doping, dye sensitization, composite semiconductor, anion doping and metal ion implantation. This paper aims to review the up to date development of the above mentioned technologies applied to TiO2 photocatalytic hydrogen production. Based on the studies reported in the literature, metal ion implantation and dye sensitization are very effective methods to extend the activating spectrum to the visible range. Therefore, they play an important role in the development of efficient photocatalytic hydrogen production.
author_names: Meng Ni

Michael K H Leung

Dennis Yiu Cheong Leung

K Sumathy
title: A review and recent developments in photocatalytic water splitting using TiO2 for hydrogen production
year: 2007

abstract: Conjugated carbon nitride (CN) is an emerging and promising semiconductor photocatalyst for water photolysis owing to its unique properties. However, the traditional thermally induced polymerization of N containing precursors typically produces melon based CN solids with amorphous or semi crystalline structures with only moderate photocatalytic performance. Many strategies have been developed to prepare crystalline CNs (CCNs) such as high temperature and high pressure routes, ionothermal synthesis, and microwave assisted synthesis. In this Minireview, we summarize the progress that has been made in the synthesis of CCNs and their application in photocatalytic water splitting reactions. Three kinds of CCNs are mainly discussed according to their polymeric subunits. Challenges associated with CCNs and their future development are also included.
author_names: Lihua Lin

Zhiyang Yu

Xinchen Wang
title: Crystalline Carbon Nitride Semiconductors for Photocatalytic Water Splitting.
venue: Angewandte Chemie
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: Abstract As the world decides on the next giant step for the renewable energy revolution, scientists have begun to reinforce their headlong dives into the exploitation of solar energy. Hitherto, numerous attempts are made to imitate the natural photosynthesis of plants by converting solar energy into chemical fuels which resembles the "Z scheme" process. A recreation of this system is witnessed in artificial Z scheme photocatalytic water splitting to generate hydrogen (H2) This work outlines the recent significant implication of the Z scheme system in photocatalytic water splitting, particularly in the role of electron mediator and the key factors that improve the photocatalytic performance. The Review begins with the fundamental rationales in Z scheme water splitting, followed by a survey on the development roadmap of three different generations of Z scheme system: 1) PS A/D PS (first generation) 2) PS C PS (second generation) and 3) PS PS (third generation) Focus is also placed on the scaling up of the "leaf to tree" challenge of Z scheme water splitting system, which is also known as Z scheme photocatalyst sheet. A detailed investigation of the Z scheme system for achieving H2 evolution from past to present accompanied with in depth discussion on the key challenges in the area of Z scheme photocatalytic water splitting are provided.
author_names: Boon-Junn Ng

Lutfi Kurnianditia Putri

Xin Ying Kong

Yee Wen Teh

Pooria Pasbakhsh

Siang-Piao Chai
title: Z Scheme Photocatalytic Systems for Solar Water Splitting
venue: Advanced science
year: 2020

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 We report the remarkable production of H2 and H2O2 from pure water using porous brookite TiO2 nanoflutes decorated with Pt nanoparticles through two electron photocatalytic intermediate water splitting (PIWS) The H2 production rate from deionized water (pH ~7.0) was 9.8 0.6 mmol mg 1 h 1, more than 12 fold and 230 fold higher than the reported TiO2 based photocatalytic overall water splitting (POWS) and H2/H2O2 production systems, respectively. The apparent quantum yields (AQY) value can achieve 43.4% which is the highest value compared with the reported TiO2 based POWS systems and the commercial value for PIWS is ~9 fold higher than that for POWS even ignoring the separation cost. The mechanism of the distinct performance was confirmed by DFT and experimental measurements. The present work provides a feasible strategy to significantly improve the process efficiency and value of photocatalytic water splitting in both pure water and seawater using natural sunlight.
author_names: Shuang Cao

Ting Shan Chan

Ying-Rui Lu

Xinghua Shi

Bing Fu

Hongmei Li

Kang Liu

Sarah Alzuabi

Ping Cheng

Min Liu

Tao Li

Xiaobo Chen

Lingyu Piao
title: Photocatalytic pure water splitting with high efficiency and value by Pt/porous brookite TiO2 nanoflutes
year: 2020

abstract: Abstract Recently, g C 3 N 4 has exhibited excellent catalytic performances in photocatalytic water splitting for H 2 and O 2 generation, degradation of pollutants and CO 2 reduction. However, the bulk g C 3 N 4 demonstrates some disadvantages such as low specific surface area, high defect density, fast recombination possibility of photogenerated electron hole pairs, and non recyclable characteristics, leading to low photocatalytic performance and efficiency. The three dimensional (3D) network like g C 3 N 4 composite materials constructed by nanotechnology can effectively improve the adsorption capacity, light response, structure stability and recyclability of photocatalysts, which results in a significant increase in the photocatalytic performance and utilization. It is a novel way to achieve high efficient separation of photogenerated electron hole pairs and improve photocatalytic activity. In this review, the recent research progresses especially the synthesis strategy of 3D g C 3 N 4 composite photocatalysts and their applications for photocatalytic water splitting, degradation of organic pollutants and CO 2 reduction are firstly and systematically introduced and discussed. The review and prospect of 3D g C 3 N 4 composite materials can provide some new ideas and directions for the research and development of 3D g C 3 N 4 composite photocatalysts with high activity, strong adsorption, facile recyclability, and no secondary pollution.
author_names: Xibao Li

Jie Xiong

Xiaoming Gao

Juntong Huang

Zhijun Feng

Zhi Chen

Yongfa Zhu
title: Recent advances in 3D g C3N4 composite photocatalysts for photocatalytic water splitting, degradation of pollutants and CO2 reduction
venue: Journal of Alloys and Compounds
year: 2019

abstract: Black phosphorus (BP) has recently drawn tremendous attention in photocatalysis for its excellent optical properties. However, limited by the rapid recombination of photogenerated carriers, the use of BP for photocatalytic water splitting still remains a huge challenge. Herein, we fabricate a black/red phosphorus (BP/RP) hetero phase junction photocatalyst by a wet chemistry method to successfully promote the interfacial charge separation and thus achieve Z scheme photocatalytic water splitting without using sacrificial agents. The Z scheme mechanism was unambiguously confirmed by time resolved transient absorption spectroscopy. This work provides a novel insight into the interface design of hetero phase junction with atomic precision.
author_names: Fulai Liu

Rui Shi

Zhuan Wang

Yuxiang Weng

Chi-Ming Che

Yong Chen
title: Direct Z Scheme Hetero phase Junction of Black/Red Phosphorus for Photocatalytic Water Splitting.
venue: Angewandte Chemie
year: 2019