Plasmonic-enhanced catalytic activity of methanol oxidation on Au–graphene–Cu nanosandwiches

Abstract

The plasmonic-enhanced catalytic activity of methanol oxidation on Au-based catalysts provides a promising strategy for direct methanol fuel cells (DMFCs) to avoid the CO poisoning of traditional Pt-based catalysts. However, the effect of surface plasmon resonance on the light-enhanced methanol oxidation activity of Au or Au-based catalysts has not been fully understood. The mechanism by which hot plasmonic carriers participate in the methanol oxidation reaction (MOR) has not been elucidated. Herein, Au nanoparticles (Au NPs) are loaded on a support of single-layer graphene–Cu contacts (SG/Cu) to construct a nanosandwich structure of a Au–graphene–Cu catalytic electrode (Au–n/SG/Cu). The Au-6T/SG/Cu catalytic electrode exhibits an MOR catalytic activity of approximately 288 μA μg⁻¹ under simulated solar light irradiation, which is approximately 1.7 times higher than that without irradiation. The chemisorption capacity of OH⁻ anions is enhanced on the Au-6T/SG/Cu catalytic electrode compared with the pure Au NP surface. The adsorbed OH⁻ anions are oxidised into ˙OH radicals by the trapped positive holes on the Au NP surface. These OH radicals possessed a high oxidation capacity for the direct oxidation of HCOO⁻ intermediates and promoted the complete methanol oxidation on Au NPs, which is beneficial for improving the fuel efficiency of DMFCs.