Promotion of the photo thermal catalytic CO2 reduction on the Ag modified BiOCl/Bi2WO6 composites

Abstract

The construction of heterojunction composites can effectively inhibit the rapid recombination of photogenerated electron-hole pairs in semiconductor catalysts. Further, the SPR effects of noble metal can promote the catalyst’s light utilization and enhance the photothermal conversion. The photothermal synergy effects may improve the CO₂ reduction ability of catalysts. In this article, Ag particles were loaded on the surfaces of BiOCl/Bi₂WO₆ heterojunction catalysts by the UV light reduction method to successfully construct a ternary composite catalyst Ag/BiOCl/Bi₂WO₆. The catalyst produces CO at 21.21 μmol/g/h rate and CH₄ at 6.41 μmol/g/h rate in the solid–gas reaction system containing CO₂ and H₂O vapor under the 300 W Xe lamp irradiation. The CO yield is 7.6 and 16.1 times that of the pure BiOCl and Bi₂WO₆, respectively. Moreover, through in situ infrared spectroscopy, photoelectrochemistry and UV–Vis DRS characterization, the intermediates, charge transfer path and reaction mechanism of CO₂ reduction with water vapor were explored. The efficient electron transfer and the SPR effect of Ag synergistically promote the photothermal CO₂ conversion performance. This work provides some new insights for the design and synthesis of Bi based catalysts in photothermal catalytic CO₂ reduction with H₂O vapor.