Photothermal CO 2 conversion to ethanol through photothermal heterojunction-nanosheet arrays.

Photothermal CO 2 conversion to ethanol offers a sustainable solution for achieving net-zero carbon management. However, serious carrier recombination and high C-C coupling energy barrier cause poor performance in ethanol generation. Here, we report a Cu/Cu 2 Se-Cu 2 O heterojunction-nanosheet array, showcasing a good ethanol yield under visible-near-infrared light without external heating. The Z-scheme Cu 2 Se-Cu 2 O heterostructure provides spatially separated sites for CO 2 reduction and water oxidation with boosted carrier transport efficiency. The microreactors induced by Cu 2 Se nanosheets improve the local concentration of intermediates (CH 3 * and CO*), thereby promoting C-C coupling process. Photothermal effect of Cu 2 Se nanosheets elevates system's temperature to around 200  ° C. Through synergizing electron and heat flows, we achieve an ethanol generation rate of 149.45 µmol g -1 h -1 , with an electron selectivity of 48.75% and an apparent quantum yield of 0.286%. Our work can serve as inspiration for developing photothermal catalysts for CO 2 conversion into multi-carbon chemicals using solar energy.