Decisive Impact of Support Functional Groups on the Catalytic Activity of Graphene-Supported Gold Nanoparticles

Graphical Change from none to one hundred percent just by a simple calcination : Directly using graphene to support gold nanoparticles gives no catalytic activity. But if the graphene support just undergoes a very simple thermal treatment for removing some oxygen-containing groups on it, a full conversion can be obtained within only half hour. Graphene is a promising support material for gold (Au) catalysts and its surface functional groups may play important roles in Au catalysis. By using alcohol oxidation with molecular oxygen as the probe, this work reveals that the oxygen-containing groups on the graphene support significantly affect the Au catalysis. The carbonyl groups can totally deactivate the catalysts. Just by thermally treating the graphene at suitable conditions to remove the carbonyl groups, the catalytic performance of the Au catalysts can be greatly improved. Even a full conversion can be obtained in a very short reaction time (just 0.5 h), when the oxygen content of the graphene support decreases from the initial 6.67% to 2.58% with the almost disappearance of C═O groups. The mechanism is also analyzed. Despite poisoning the present catalytic reaction, the Au-support interaction elucidated in this work may be beneficial to some other catalytic reactions with different reaction mechanism. Thus, this work helps to enhance the catalytic activity of graphene-supported Au catalysts, according to the applied catalytic reactions.