Fig. 2: CO2RR performance.

a CO and O2 productions over Au NPs with 420 LED light irradiation at 200 °C. b Wavelength-dependent AQEs of the Au photocatalyst (n = 3, error bars: standard deviation). c Control experiments with different reaction conditions. d The reaction temperatures and e light intensity-dependent CO production rate on Au NPs under 420 nm LED light irradiation (n = 3, error bars: standard deviation). f Photocatalytic CO2RR performance with (red curve) or without (black curve) H2O on Au NPs. g Mass spectrum from GC-MS analysis of the 13CO and 18O2 generated from photocatalytic 13CO2RR with H218O over Au NPs. h Valence-band XPS spectrum of Au. i Schematic illustration for the electronic band structure of the ~4 nm Au NPs.