Sun-simulated-driven production of high-purity methanol from carbon dioxide

Abstract

CO₂ conversion to CH₃OH under mild conditions is of particular interest yet rather challenging. Both electro- and thermo-catalytic CO₂ reduction to CH₃OH can only produce CH₃OH in low concentration (typically mixed with water), requiring energy-intensive purification processes. Here we design a sun-simulated-driven tandem catalytic system comprising CO₂ electroreduction to syngas, and further photothermal conversion into high-purity CH₃OH (volume fraction > 97%). We construct a self-supporting electrocatalyst featuring dual active sites of Ni single atoms and encapsulated Co nanoparticles, which could produce syngas with a constant H₂:CO ratio of ~2 via solar-powered CO₂ electroreduction. The generated syngas is subsequently fed into the photothermal module, which could produce high-purity CH₃OH under 1 sun-light irradiation, with a rate of 0.238 g_CH3OH g_cat^–1 h^–1. This work demonstrates a feasible and sustainable route for directly converting CO₂ into high-purity CH₃OH.