Experimental Evidence of CO2 Photoreduction Activity of SnO2 Nanoparticles.

Tin dioxide (SnO2 ) has intrinsic characteristics that do not favor its photocatalytic activity. However, we evidenced that surface modification can positively influence its performance for CO2 photoreduction in the gas phase. The hydroxylation of the SnO2 surface played a role in the CO2 affinity decreasing its reduction potential. The results showed that a certain selectivity for methane (CH4 ), carbon monoxide (CO), and ethylene (C2 H4 ) is related to different SnO2 hydrothermal annealing. The best performance was seen for SnO2 annealed at 150 °C, with a production of 20.4 μmol g-1 for CH4 and 16.45 μmol g-1 for CO, while for SnO2 at 200 °C the system produced more C2 H4 , probably due to a decrease of surface -OH groups.