Preparation of bifunctional Au-Pd/TiO2 catalysts and research on methanol liquid phase one-step oxidation to methyl formate

A series of Au-Pd/TiO2 bifunctional catalysts with different Au, Pd loading percents have been prepared by sol-immobilization method. The related XRD, HR-TEM and XPS characterizations have been undertaken to uderstand the structure of catalysts. Catalytic activity in methanol liquid phase one-step oxidation to methyl formate have been studied in batch reactor. Results show that the nanoparticles are highly dispersed on TiO2 with 6.4 nm mean size. Also, bifunctional catalysts could catalyse the conversion of methanol to methyl formate with high efficiency. With 1wt%Au-1wt%Pd/TiO2 catalysts, when the molar ratio between active components and methanol is 1/2000, the conversion of methanol is 55.7% for 4 h under 100 °C and 25 bar. At the same time, the selectivity of methyl formate is up to 74.2%. The Au-Pd/TiO2 bifunctional catalysts also shows great stability for the reaction with stable conversion and selectivity after 5 cycles