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.