Search query: Photoreduction of carbon dioxide in the presence of H2, H2O and CH4 over TiO2 and ZnO photocatalysts

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abstract: Abstract In this study, efficiency of the prepared photocatalysts (TiO2 and ZnO) on stainless steel mesh network was examined for photoreduction of CO2 gas. The experiments were performed under direct UV irradiation in a self designed batch reactor. UV visible spectra and XRD pattern showed that crystalline structure of the particles did not change in calcinations process. Also, SEM images indicated that semiconductors were well coated on the surface of the mesh. Conversion results showed that photoreduction of CO2 in the presence of TiO2 photocatalyst with H2O reductant had highest conversion. However, the best conversion efficiency for ZnO was achieved in the presence of CH4 molecules. The conversion products in the presence of CH4 as reductant can be formate and acetate derivatives, whereas the conversion products in the presence of H2 can be assigned to the production of methane and formic derivatives.
author_names: Ghader Mahmodi

Shahram Sharifnia

M Madani

Vahid Vatanpour
title: Photoreduction of carbon dioxide in the presence of H2, H2O and CH4 over TiO2 and ZnO photocatalysts
year: 2013

abstract: Abstract The photocatalytic reduction of carbon dioxide (CO 2 was studied in a self designed circulated photocatalytic reaction system under titanium dioxide (TiO 2 Degussa P 25) and zirconium oxide (ZrO 2 photocatalysts and reductants at room temperature and constant pressure. The wavelengths of incident ultraviolet (UV) light for the photocatalysis of TiO 2 and ZrO 2 were 365 and 254 nm, respectively. Experimental results indicated that the highest yield of the photoreduction of CO 2 were obtained using TiO 2 with H 2 +H 2 O and ZrO 2 with H 2 Photoreduction of CO 2 over TiO 2 with H 2 +H 2 O formed CH 4 CO, and C 2 H 6 with the yield of 8.21, 0.28, and 0.20 mmol/g, respectively, while the photoreduction of CO 2 over ZrO 2 with H 2 formed CO at a yield of 1.24 mmol/g. The detected reaction products supported the proposition of two reaction pathways for the photoreduction of CO 2 over TiO 2 and ZrO 2 with H 2 and H 2 O, respectively. Additionally, a one site Langmuir Hinshewood (L H) kinetic model was successfully applied to simulate the photoreduction rate of CO 2
author_names: C C Lo

Chung Hsuang Hung

Chung-shin Yuan

Jeng-Fong Wu
title: Photoreduction of carbon dioxide with H2 and H2O over TiO2 and ZrO2 in a circulated photocatalytic reactor
year: 2007

abstract: Zirconium oxide is active for photoreduction of gaseous carbon dioxide to carbon monoxide with hydrogen. A stable surface species arises under the photoreduction of CO2 on zirconium oxide and is identified as surface formate by IR spectroscopy. Adsorbed CO2 is converted to formate by photoreaction with hydrogen. The surface formate is a true reaction intermediate since CO is formed by the photoreaction of formate and CO2; surface formate works as a reductant of carbon dioxide to yield carbon monoxide. The dependence on the wavelength of irradiation light shows that bulk ZrO2 is not the photoactive species. When ZrO2 adsorbs CO2 a new band appears in the photoluminescence excitation spectrum. The photoactive species in the reaction between CO2+H2 which yields HCOO is presumably formed by the adsorption of CO2 on the ZrO2 surface.
author_names: Yoshiumi Kohno

Tsunehiro Tanaka

Takuzo Funabiki

Satohiro Yoshida
title: Identification and reactivity of a surface intermediate in the photoreduction of CO2 with H2 over ZrO2
year: 1998

abstract: This critical review shows the basis of photocatalytic water splitting and experimental points, and surveys heterogeneous photocatalyst materials for water splitting into H2 and O2, and H2 or O2 evolution from an aqueous solution containing a sacrificial reagent. Many oxides consisting of metal cations with d0 and d10 configurations, metal (oxy)sulfide and metal (oxy)nitride photocatalysts have been reported, especially during the latest decade. The fruitful photocatalyst library gives important information on factors affecting photocatalytic performances and design of new materials. Photocatalytic water splitting and H2 evolution using abundant compounds as electron donors are expected to contribute to construction of a clean and simple system for solar hydrogen production, and a solution of global energy and environmental issues in the future (361 references)
author_names: Akihiko Kudo

Yugo Miseki
title: Heterogeneous photocatalyst materials for water splitting.
venue: Chemical Society reviews
year: 2009

abstract: Photocatalysts and Photoelectrodes James L. White, Maor F. Baruch, James E. Pander III, Yuan Hu, Ivy C. Fortmeyer, James Eujin Park, Tao Zhang, Kuo Liao, Jing Gu, Yong Yan, Travis W. Shaw, Esta Abelev, and Andrew B. Bocarsly* +Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States +Chemical and Materials Science Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States
author_names: James L White

Maor F Baruch

James E Pander Iii

Yuan Hu

Ivy C Fortmeyer

James Eujin Park

Tao Zhang

Kuo Liao

Jing Gu

Yong Yan

Travis W Shaw

Esta Abelev

Andrew B Bocarsly
title: Light Driven Heterogeneous Reduction of Carbon Dioxide: Photocatalysts and Photoelectrodes.
venue: Chemical reviews
year: 2015

abstract: Jenny Schneider, Masaya Matsuoka, Masato Takeuchi, Jinlong Zhang, Yu Horiuchi, Masakazu Anpo, and Detlef W. Bahnemann* +Institut fur Technische Chemie, Leibniz Universitat Hannover, Callinstrasse 3, D 30167 Hannover, Germany +Faculty of Engineering, Osaka Prefecture University, 1 Gakuen cho, Sakai Osaka 599 8531, Japan Key Lab for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237, China
author_names: Jenny Schneider

Masaya Matsuoka

Masato Takeuchi

Jinlong Zhang

Yu Horiuchi

Masakazu Anpo

Detlef W Bahnemann
title: Understanding TiO2 photocatalysis: mechanisms and materials.
venue: Chemical reviews
year: 2014

abstract: Abstract Photoreduction of CO 2 to hydrocarbons is a sustainable energy technology which not only mitigates emissions but also provides alternative fuels. However, one of the largest challenges is to increase the overall CO 2 photo conversion efficiency when water is used as the reducing reagent. In this work, mesoporous silica supported Cu/TiO 2 nanocomposites were synthesized through a one pot sol gel method, and the photoreduction experiments were carried out in a continuous flow reactor using CO 2 and water vapor as the reactants under the irradiation of a Xe lamp. The high surface area mesoporous silica substrate >300 m 2 /g) greatly enhanced CO 2 photoreduction, possibly due to improved TiO 2 dispersion and increased adsorption of CO 2 and H 2 O on the catalyst. CO was found to be the primary product of CO 2 reduction for TiO 2 SiO 2 catalysts without Cu. The addition of Cu species, which was identified to be Cu 2 O by the XPS, markedly increased the overall CO 2 conversion efficiency as well as the selectivity to CH 4 by suppressing the electron hole recombination and enhancing multi electron reactions. A synergistic effect was observed by combining the porous SiO 2 support and the deposition of Cu on TiO 2 The peak production rates of CO and CH 4 reached 60 and 10 mmol g cat 1 h 1 respectively, for the 0.5%Cu/TiO 2 SiO 2 composite that has the optimum Cu concentration; the peak quantum yield was calculated to be 1.41% Deactivation and regeneration of the catalyst was observed and the mechanism was discussed. Desorption of the reaction intermediates from the active sites may be the rate limiting step.
author_names: Ying Li

Wei-Ning Wang

Zili Zhan

Myung-Heui Woo

Chang-Yu Wu

Pratim Biswas
title: Photocatalytic reduction of CO2 with H2O on mesoporous silica supported Cu/TiO2 catalysts
year: 2010

abstract: Abstract ATaO3 (A Li, Na, K) compound oxides exhibit photocatalytic activity for the reduction of CO2 in the presence of H2. Only CO gas was generated over all samples under photoirradiation. The photocatalytic activity was higher in the order corresponding to KTaO3, NaTaO3 and LiTaO3 (LiTaO3 NaTaO3 KTaO3) The order of the photocatalytic activities was consistent with that of the Eg (optical gap) values. After 24 h of photoirradiation, the amount of evolved CO reached 0.42 mmol g 1 over LiTaO3. TPD experiments indicated that the broad peak which is assigned to chemisorbed CO2 gas was observed at 573 K in the case of LiTaO3. On the contrary, there was no peak in the spectra of NaTaO3 and KTaO3. The amount of evolved CO gas almost strongly depends on the amount of chemisorbed CO2 in the case of ATaO3 (A Li, Na, K) In addition, the photocatalytic activity increased with increasing the calcination temperature of LiTaO3. This means that a smooth charge separation in a LiTaO3 photocatalyst and chemisorption of CO2 on the surface contribute to effective reduction of CO2 in the presence of H2.
author_names: Kentaro Teramura

Shin-ichi Okuoka

Hideo Tsuneoka

Tetsuya Shishido

Tsunehiro Tanaka
title: Photocatalytic reduction of CO2 using H2 as reductant over ATaO3 photocatalysts (A Li, Na, K)
year: 2010

abstract: Recently, there has been an increasing interest in the research of photocatalytic reduction of CO2 with H2O, an innovative way to simultaneously reduce the level of CO2 emissions and produce renewable and sustainable fuels. Titanium dioxide (TiO2) and modified TiO2 composites are the most widely used photocatalysts in this application; however, the reaction mechanism of CO2 photoreduction on TiO2 photocatalysts is still not very clear, and the reaction intermediates and product selectivity are not well understood. This review aims to summarize the recent advances in the exploration of reaction mechanism of CO2 photoreduction with H2O in correlation with the TiO2 photocatalyst characteristics. Discussions are provided in the following sections: (1) CO2 adsorption, activation and dissociation on TiO2 photocatalyst; (2) mechanism and approaches to enhance charge transfer from photocatalyst to reactants (i.e. CO2 and H2O) and (3) surface intermediates, reaction pathways, and product selectivity. In each section, the effects of material properties are discussed, including TiO2 crystal phases (e.g. anatase, rutile, brookite, or their mixtures) surface defects (e.g. oxygen vacancy and Ti^(3+ and material modifications (e.g. incorporation of noble metal, metal oxide, and/or nonmetal species to TiO2) Finally, perspectives on future research directions and open issues to be addressed in CO2 photoreduction are outlined in this review paper.
author_names: Lianjun Liu

Ying Li
title: Understanding the Reaction Mechanism of Photocatalytic Reduction of CO2 with H2O on TiO2 Based Photocatalysts: A Review
year: 2014

abstract: Photocatalytic reduction of carbon dioxide (CO2) into hydrocarbon fuels such as methane is an attractive strategy for simultaneously harvesting solar energy and capturing this major greenhouse gas. Incessant research interest has been devoted to preparing graphene based semiconductor nanocomposites as photocatalysts for a variety of applications. In this work, reduced graphene oxide (rGO) TiO2 hybrid nanocrystals were fabricated through a novel and simple solvothermal synthetic route. Anatase TiO2 particles with an average diameter of 12 nm were uniformly dispersed on the rGO sheet. Slow hydrolysis reaction was successfully attained through the use of ethylene glycol and acetic acid mixed solvents coupled with an additional cooling step. The prepared rGO TiO2 nanocomposites exhibited superior photocatalytic activity (0.135 mmol gcat 1 h 1) in the reduction of CO2 over graphite oxide and pure anatase. The intimate contact between TiO2 and rGO was proposed to accelerate the transfer of photogenerated electrons on TiO2 to rGO, leading to an effective charge anti recombination and thus enhancing the photocatalytic activity. Furthermore, our photocatalysts were found to be active even under the irradiation of low power energy saving light bulbs, which renders the entire process economically and practically feasible.
author_names: Lling-Lling Tan

Wee-Jun Ong

Siang-Piao Chai

Abdul Rahman Mohamed
title: Reduced graphene oxide TiO2 nanocomposite as a promising visible light active photocatalyst for the conversion of carbon dioxide
venue: Nanoscale Research Letters
year: 2013