Laser-synthesized graphite carbon encased gold nanoparticles with specific reaction channels for efficient oxygen reduction

Abstract

Developing novel electrocatalysts with desirable activity and stability is always full of challenge in electrochemical energy conversion. Here, specific carbon shell encapsulated Au (Au@C) nanoparticles are prepared by a laser ablation in liquids method and used as the oxygen reduction reaction (ORR) electrocatalysts. Such Au@C nanoparticles exhibit excellent catalytic activity toward ORR with an onset potential of 0.98 V and a half-wave potential of 0.87 V, better than that of commercial Pt/C. More importantly, the Au@C catalyst exhibits unrivalled stability for 3000 CV cycles for ORR in 0.1 M KOH, dramatically superior to Pt/C and pure Au catalysts. The density functional theory (DFT) calculations and SCN− ions to poison metal-based active sites are conducted to Au@C catalyst, and the results indicate that the structural defects of carbon shells supply an access for the reactants to contact the core Au nanoparticles, causing the catalytic reaction, meanwhile the carbon shells prevent the degeneration of core Au nanoparticles in the harsh electrolytes enhancing the durability of Au effectively.