Photocatalytic Reduction of CO2 Using Titanium Dioxide and Metal–Semiconductor Nanostructures Made from Titanium Dioxide

Ovcharov, M. L.; Shvalagin, V. V.; Shcherban, N. D.; Nazarkovskii, M. A.; Granchak, V. M.

doi:10.1007/s11237-013-9311-0

Cited by 9 publications

(4 citation statements)

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“…The photoreduction of the metals was chosen, on the one hand, as a model process for studying the photocatalytic properties of double tin oxide under the influence of visible light. On the other, the metal-semiconducting nanocomposites formed during the reaction can have unusual photo-and electrophysical characteristics [4,5] and can also exhibit enhanced photocatalytic activity in reduction processes compared with the individual semiconductors [6,7]. Certain features of the hydrothermal production of Sn 3 O 4 not mentioned in [2,3], although as shown in the present work they do radically affect the formation of the double tin oxide, were also established.…”

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Photochemical Reduction of Silver and Tetrachloroaurate Ions on the Surface of Nanostructured Sn3O4 Under the Influence of Visible Light

et al. 2015

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The double tin oxide Sn 3 O 4 with plate morphology was obtained. It was found that such semiconducting materials are photochemically active under the influence of visible light with l > 435 nm in the photoreduction of silver ions and tetrachloroaurate to the respective metals by water with the formation of composite nanostructures. It was shown that the rate of photoreduction of silver ions to metal is substantially lower in the absence of air due, possibly, to photodegradation of the semiconductor.In the last few decades nanostructured particles of semiconductors have aroused interest in connection with their possible use in a whole series of oxidation-reduction photocatalytic processes: release of hydrogen from water, reduction of carbon dioxide, reduction of metal ions, photopolymerization, oxidation of contaminants in water or air, etc.[1]. Among the disadvantages of such materials it is possible to mention their low sensitivity to visible light, which makes it possible to use only a small part of the energy of sunlight. At the same time materials sensitive to visible light very often have clearly defined toxicity (CdS, CdSe, PbS), which significantly limits their widespread use. An urgent task in this connection is the search for and investigation of new nontoxic semiconducting materials that are sensitive to visible light. One such substance is the double tin oxide Sn 3 O 4 , which according to [2,3] can exhibit photocatalytic activity in the decomposition of water and methylene orange under the influence of light with l > 400 nm.In the present work we investigated the photocatalytic activity of the double tin oxide under the influence of visible light with l > 435 nm in the reduction of silver and tetrachloroaurate ions to the respective metals. The photoreduction of the metals was chosen, on the one hand, as a model process for studying the photocatalytic properties of double tin oxide under the influence of visible light. On the other, the metal-semiconducting nanocomposites formed during the reaction can have unusual photo-and electrophysical characteristics [4,5] and can also exhibit enhanced photocatalytic activity in reduction processes 0040-5760/15/5103-0177

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Photochemical Reduction of Silver and Tetrachloroaurate Ions on the Surface of Nanostructured Sn3O4 Under the Influence of Visible Light

et al. 2015

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“…Copper-deposited titanium dioxide (Cu/TiO 2 ) has been extensively studied for the photocatalytic reduction of CO 2 with H 2 O, − an artificial photosynthesis process that holds potential to supply a renewable energy and a sustainable environment. − The Cu species in the Cu/TiO 2 composites serve as a cocatalyst providing reaction sites and promoting the separation and transport of photoexcited charge carriers (electron–hole pairs), largely depending on the chemical valence of Cu. Highly dispersed surface Cu + species are often reported to be the most active compared to Cu 2+ and Cu 0 , ,,, while other researchers suggested Cu 2+ or Cu 0 as the most active species. ,, Our previous work tailored the Cu valence in Cu-deposited P25 TiO 2 and revealed the roles of Cu species in enhancing CO 2 conversion efficiency .…”

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Mechanistic Study of CO₂ Photoreduction with H₂O on Cu/TiO₂ Nanocomposites by in Situ X-ray Absorption and Infrared Spectroscopies

et al. 2016

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Cu/TiO2 composites are extensively studied for photocatalytic reduction of CO2 with H2O, but the roles of Cu species (Cu2+, Cu+, or Cu0) is not well understood, and the photocatalyst deactivation mechanism is seldom addressed. In this work, we have employed in situ techniques, i.e., X-ray absorption spectroscopy (XAS) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), to explore the surface chemistry of Cu/TiO2 composites under CO2 photoreduction environment. We found that the air-calcined Cu/TiO2 (Cu/Ti(air)) surface was dominated by isolated Cu2+ sites, while the one post-treated with H2 at 200 °C (Cu/Ti(H2)) was rich in Cu+ and oxygen vacancy (VO). Cu/Ti(H2) showed more than 50% higher activity than Cu/Ti(air) for CO2 photoreduction to CO, mainly resulting from the synergy of Cu+, OH groups, and VO that could scavenge holes to enhance electron transfer, provide CO2 adsorption sites, and facilitate the activation and conversion of the adsorbed CO2 (HCO3 – and CO2 –). Meanwhile, the consumption of OH groups and Cu+ active sites by holes may result in the deactivation of Cu/Ti(H2). Moreover, in situ XAS results directly demonstrated that (1) the photoinduced oxidation of Cu+ to Cu2+ changed the surrounding environments of Cu by increasing the coordination number; (2) thermal treatment by H2 could not fully recover the OH and Cu+ sites to their original states; and (3) adding hole scavengers (e.g., methanol) maintained or even increased the more active Cu+ species from the photoreduction of Cu2+, thus leading to a higher and more stable CO2 reduction activity. Findings in this work and the application of in situ XAS technique will help develop a more efficient photocatalyst for CO2 photoreduction and advance the understanding of the reaction mechanism and surface chemistry.

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“…The photoreduction of carbon dioxide depends significantly on the presence of electron donors in the system, which efficiently trap the valence band holes in the metal-semiconductor anode, thereby hindering undesired electron-hole recombination [10] and facilitating greater transfer of electrons to the copper counter-electrode. We studied the possibility of using organic wastes in alcohol production as integral components of electrochemical cells for solar energy conversion.…”

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Effect of the Morphology of TiO2/Ti Electrodes on Photoactivity in the Electrochemical Reduction of Carbon Dioxide

et al. 2014

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UDC 544.526.5, 544.653.3 M. L. Ovcharov, A. M. Mishura, V. V. Shvalagin, and V. M . GranchakA study was carried out on the photoelectrochemical reduction of CO 2 using TiO 2 /Ti photoelectrodes, whose activity increases in going from samples obtained by dip-coating method to films formed by electrochemical anodization of titanium and further increases in going from disordered structures (spongy structure) to ordered nanotube structure. The introduction of electron donors into the anode chamber of the photoelectrochemical cell considerably enhances the photoactivity of the system. In the series of electron donors studied, this photoactivity increases in the The photoelectrochemical reduction of CO 2 is a promising method for the conversion of solar energy into chemical energy, whose practical realization would permit us not only to obtain electrical energy and produce organic products from carbon dioxide [1] but also facilitate the use of organic wastes as secondary energy sources [2]. Intensive research is now underway on the photoelectrochemical production of organic compounds from carbon dioxide using various semiconductor electrodes [3]. However, there has been hardly any systematic investigation of the role of the morphology of semiconductor photoelectrode in the photoelectrochemical reduction of CO 2 even though this factor is known to have a significant effect on the activity of such electrodes [4].In the present work, we investigated the relationship between the morphology of the surface of TiO 2 /Ti electrodes, obtained both by electrochemical anodization under various conditions and by the sol-gel method, and the activity of these materials as anodes in the photoelectrochemical reduction of CO 2 . EXPERIMENTALMesoporous films of titanium dioxide (meso-TiO 2 /Ti) were obtained by the sol-gel method upon the hydrolysis of titanium tetraisopropoxide obtained from Aldrich in the presence of BASF Pluronic P123 triblock-copolymer of ethylene oxide and propylene as the template [5]. The films were deposited onto a titanium plate by dip-coating method with deposition rate 1.5 mm/s. After deposition, the films were left in the air for 2 h and then roasted in a muffle furnace at 400°C for 2 h. In the experiments, we used six-layer coatings obtained by consecutive film deposition after drying of each layer in the air. 2180040-5760/14/5004-0218

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Photocatalytic Reduction of CO2 Using Titanium Dioxide and Metal–Semiconductor Nanostructures Made from Titanium Dioxide

Cited by 9 publications

References 10 publications

Photochemical Reduction of Silver and Tetrachloroaurate Ions on the Surface of Nanostructured Sn3O4 Under the Influence of Visible Light

Photochemical Reduction of Silver and Tetrachloroaurate Ions on the Surface of Nanostructured Sn3O4 Under the Influence of Visible Light

Mechanistic Study of CO₂ Photoreduction with H₂O on Cu/TiO₂ Nanocomposites by in Situ X-ray Absorption and Infrared Spectroscopies

Effect of the Morphology of TiO2/Ti Electrodes on Photoactivity in the Electrochemical Reduction of Carbon Dioxide

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Photocatalytic Reduction of CO2 Using Titanium Dioxide and Metal–Semiconductor Nanostructures Made from Titanium Dioxide

Cited by 9 publications

References 10 publications

Photochemical Reduction of Silver and Tetrachloroaurate Ions on the Surface of Nanostructured Sn3O4 Under the Influence of Visible Light

Photochemical Reduction of Silver and Tetrachloroaurate Ions on the Surface of Nanostructured Sn3O4 Under the Influence of Visible Light

Mechanistic Study of CO2 Photoreduction with H2O on Cu/TiO2 Nanocomposites by in Situ X-ray Absorption and Infrared Spectroscopies

Effect of the Morphology of TiO2/Ti Electrodes on Photoactivity in the Electrochemical Reduction of Carbon Dioxide

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Mechanistic Study of CO₂ Photoreduction with H₂O on Cu/TiO₂ Nanocomposites by in Situ X-ray Absorption and Infrared Spectroscopies