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

Graphical abstract Highlights • Bifunctional catalysts supported on titanium were prepared. • One step methanol liquid oxidation to formic acid and methyl formate was achieved. • Selectivity of products could be tailored through Au and Pd weight percent. Abstract A series of Au-Pd/TiO 2 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 TiO 2 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/TiO 2 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/TiO 2 bifunctional catalysts also shows great stability for the reaction with stable conversion and selectivity after 5 cycles. [ABSTRACT FROM AUTHOR]