Noble-Metal-Free Heterojunction Photocatalyst for Selective CO2Reduction to Methane upon Induced Strain Relaxation

Das, R and Sarkar, S and Kumar, R and D Ramarao, S and Cherevotan, A and Jasil, M and Vinod, CP and Singh, AK and Peter, SC (2022) Noble-Metal-Free Heterojunction Photocatalyst for Selective CO2Reduction to Methane upon Induced Strain Relaxation. In: ACS Catalysis . pp. 687-697.

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Abstract

Sunlight-driven CO2 hydrogenation has drawn tremendous attention. However, selective CH4 formation via CO2 photoreduction is very challenging. Herein, we report a metal oxide semiconductor heterojunction consisting of BiVO4 and WO3 as a photocatalyst for the efficient conversion of carbon dioxide (CO2) selectively to methane (105 μmol g-1 h-1) under visible light in the absence of a sacrificial agent. Wise selection of the reaction medium and the strategically tuned heterojunction upon strain relaxation suppresses the competitive hydrogen generation reaction. The detailed photophysical, photoelectrochemical, and X-ray absorption spectroscopy studies pointed to the Z-scheme mechanism of electron transfer, which favors superior electron and hole separation compared to the individual components of the composite catalyst and other well-known photocatalysts reported for CO2 reduction. The observations are further corroborated by experimental diffuse reflectance infrared Fourier transform spectroscopy and theoretical density-functional theory calculations, which reveal that the heterojunction has a lower free-energy barrier for CO2 conversion to CH4 due to the larger stabilization of the*CH2O intermediate on the strain-relaxed heterojunction surface, in comparison to the pristine BiVO4 surface. The present work provides fundamental insights for constructing high-performance heterojunction photocatalysts for the selective conversion of CO2 to desired chemicals and fuels. © 2021 American Chemical Society.

Item Type:	Journal Article
Publication:	ACS Catalysis
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to American Chemical Society
Keywords:	Bismuth compounds; Carbon dioxide; Density functional theory; Fourier transform infrared spectroscopy; Free energy; Heterojunctions; Hydrogen production; Oxide semiconductors; Precious metals; Tungsten compounds, CO 2 reduction; CO2 hydrogenation; Induced strain; Metal free; Metal oxide semiconductor heterojunctions; Photo reduction; Reaction media; Sacrificial agents; Visible light; Z-scheme, Methane
Department/Centre:	Division of Chemical Sciences > Materials Research Centre
Date Deposited:	20 Jan 2022 06:51
Last Modified:	20 Jan 2022 06:51
URI:	http://eprints.iisc.ac.in/id/eprint/70978

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