Study of photocatalytic reaction of methanol with water over Rh-, and Pd-loaded TiO2 catalysts. The role of added alkali metal cations

Abstract

The product selectivity of the photocatalytic reaction of methanol with water is changed drastically by the addition of alkali metal cations to Rh- and Pd-loaded TiO2 catalysts. Over alkali metal cation free catalysts, the main products are 1:1 ratio of H2 and dimethoxymethane, which is replaced with H2, methyl formate, and CO2 over alkali metal cation added catalysts. The role of added alkali metal cations is the stabilization of the reaction intermediate as adsorbed formate instead of adsorbed formaldehyde, which causes the selectivity change from dimethoxymethane to methyl formate.