Ultrathin porous g-C3N4 nanosheets modified with AuCu alloy nanoparticles and C-C coupling photothermal catalytic reduction of CO to ethanol

Here, we report ultrathin porous g-C3N4 nanosheets modified with AuCu alloy NPs for photothermalcatalytic CO2 reduction to ethanol. The positive charge on the Au surface improves the adsorption of CO2 molecules and the charge transfer from Au to Cu in the alloy enriches Cu with excessive negative charges, promoting the formation of intermediates CO2·- and *CO on the surface of Cu. The strong interaction between the metal and g-C3N4 accelerates the migration of photogenerated charges. The increase of temperature leads to the enhancement of the thermal motion of the molecules, resulting in the synergy of photocatalysis and thermal catalysis, which promotes the formation of C-C coupling by *CO polymerization, so that the yield of CH3CH2OH was increased. At 120 ℃, the yield and selectivity of ethanol are 0.89 mmol·g−1·h−1 and 93.1% for 1.0 wt% AuCu/g-C3N4, which are 4.2 times that of photocatalysis and 7.6 times that of thermal catalysis.