The effects of gold nanosize for the exploitation of furfural by selective oxidation

An Au/ZrO2 catalyst was prepared and characterized in order to study the role of gold nanosize in the conversion of furfural into methyl furoate by oxidative esterification with O2 and methanol, without NaCH3O. The comparison with the Au/TiO2 reference catalyst provided by the World Gold Council and with an Au/ZrO2 catalyst treated at 600 ◦C in oxygen emphasized very good catalytic performances. Highly dispersed Au was evidenced on Au/ZrO2 by quantitative CO chemisorption, HRTEM analysis and FTIR spectroscopy of adsorbed CO. On the contrary, the thermal treatment at 600 ◦C results in the presence of nanoparticles larger than 4 nm that make the catalyst poorly active and selective. The Au clusters and their ability in the activation of the O2 molecule play a key role in the reaction.