Effect of H2 gas as a reductant on photoreduction of CO2 over a Ga2O3 photocatalyst

Ga2O3 was used as a photocatalyst for the photoreduction of CO2 in the presence of H2 as a reductant; in this process CO gas was selectively produced at room temperature and ambient pressure. The optimum conversion of CO2 was approximately 3% using β-Ga2O3 calcined at 1073 K for 6 h. The formation of CO depended on the amounts of H2 and CO2 introduced into the system. The photoreduction of CO2 on Ga2O3 involves two chemisorbed species—H2 and CO2. This implies that the photocatalytic reaction would proceed on the basis of the typical Langmuir–Hinshelwood mechanism.