Photocatalytic Reduction of CO_2 Using H_2 as Reductant over Solid Base Photocatalysts

摘要

We have found that CO is generated as a result of the photocatalytic reduction of CO2 in the presence of H_2 or CH4 over ZrO_2 in 1997, Rh/TiO_2 in 1999, MgO in 2001, and Ga_2O_3 in 2008. With the exception of Rh/TiO_2, these solid materials exhibit the properties of solid base catalysts; therefore, CO_2 can be adsorbed on the surface of these materials. We have insisted on the importance of CO_2 adsorption on the surface because this makes CO_2, which is a stable and linear molecular, into an active species which provides abundant reactivity for the photocatalytic reduction of CO_2. The determining factor for photocatalytic reduction is the adsorption of CO_2 on the surface. In the following section, we provide an overview of some solid base materials which exhibit the photocatalytic activity necessary for photocatalytic reduction of CO_2 in the presence of H_2.