Photothermal catalytic CO2 hydrogenation to methanol

Abstract

Utilization of waste CO₂ to replace traditional fossil-based resources for the production of valuable fuels or chemicals is an ideal strategy to release the pressure on energy and environment. As a platform molecule with both energy carrier and chemical feedstock attributes, methanol (CH₃OH)'s synthesis has attracted increasing attention, especially with CO₂ feedstock. Different from the traditional syngas pathway requiring high temperature and pressure, high energy input and expensive H₂, the photothermal technology for CH₃OH synthesis from CO₂ has milder reaction conditions, and utilizes renewable solar energy and green H₂O as the hydrogen source by coupling light energy capture with the thermocatalytic process. Although many encouraging results have been reported in photothermal CO₂ hydrogenation to CH₃OH, a systematic summary on the recent development of photothermal CO₂ hydrogenation to CH₃OH is lacking. In this review, we first introduce the significance of CO₂ valoration and CH₃OH as well as the thermodynamic property of CO₂ hydrogenation to CH₃OH, then discuss the advantages and nature of photothermal catalysis, summarize the development and common design strategies of photothermal catalysts for CO₂ hydrogenation to CH₃OH, and finally elucidate the nature of three reaction mechanisms, namely photo-driven thermocatalysis, photo-assisted thermocatalysis and thermal-assisted photocatalysis, and give several examples how to distinguish them. This review will be helpful to stimulate the design of active catalysts and deepen the understanding of reaction mechanisms, thus advancing the development of this technology.