Silver-Based Plasmonic Catalysts for Carbon Dioxide Reduction

Light-enhanced valorization of CO2 provides a potentially useful pathway to offsetting carbon emissions to the atmosphere. Ni, a thermally active metal for the methanation of CO2, was coupled with Ag, a metal that exhibits a surface plasmon resonance effect in the visible light region, with the intention of exploiting the catalytic CO2 conversion by Ni and light enhancement from Ag. The catalytic metals were loaded onto an insulating silica support and exposed to 405 nm laser light during the reaction. The impact of the Ni-Ag bimetallic interaction intimacy on the influence of the light illumination on CO2 conversion and CH4 selectivity was examined. Sequentially impregnating Ni and Ag (regardless of the order) provided a stronger bimetallic interaction relative to the coimpregnation procedure. The coimpregnated sample, with the weakest metallic interaction, exhibited the highest CH4 productivity in the dark, while irradiating the catalyst at 405 nm had minimal impact on its performance. The poor photoeffect was attributed to the lack of interaction between Ni and Ag in conjunction with the low catalytic activity of Ag. The sequentially impregnated samples, which facilitated a stronger bimetallic interaction, exhibited an increase in CO2 conversion when illuminated, with the greatest improvement produced when Ni was loaded first. The increase in CO2 conversion under laser irradiation was attributed to the contribution of the Ag photoresponse. Comparing the three bimetallic catalysts clearly revealed that Ni-Ag/SiO2 with the strongest bimetallic interaction delivered the highest photoenhancement in terms of both CO2 conversion and CH4 selectivity.