Selective CH4 production by Photocatalytic CO2 Conversionusing Zn-based Polyoxometalate

Abstract

The development of photocatalytic CO2 reduction reaction (CO2RR) systems can be considered one of the solutions to address ongoing energy and climate change issues. However, it is difficult to increase both the efficiency and selectivity for CO2RR due to the presence of various reaction pathways, competitive reactions, and high energy consumption. Here, we report the synthesis of Zn-based polyoxometalate (ZnPOM) and its application in photocatalytic CO2RR for selective CH4 production. Znbased catalysts are conventionally known as catalysts for CO production from CO2RR. Interestingly, however, ZnPOM can selectively produce CH4 production in the presence of an Ir-based photosensitizer (TIr3). We present the photophysical and computational analysis to understand for selectively producing CH4 through photocatalytic CO2RR using ZnPOM as a catalyst: (1) fast charge transfer from TIr3 to ZnPOM through the strong molecular interaction between them; (2) effective electronic interaction between ZnPOM and *CO intermediates due to significant hybridization of their molecular orbitals; (3) appropriate strength of *CO binding energy in ZnPOM. This study can provide insights into the design of CO2RR catalyst beyond the conventional limitation for CH4 production that focused on Cu-based materials.