Direct access to aggregation-free and small intermetallic nanoparticles in ordered, large-pore mesoporous carbon for an electrocatalyst

Abstract

An intermetallic catalyst with ordered atomic arrays has a higher electrocatalytic activity than alloy, but the high temperature required for the formation makes the particles large, resulting in low mass activity. We report the simple synthesis of small Pt-based intermetallic nanoparticles on a carbon-based ordered mesoporous support by combining block copolymer-assisted evaporation-induced self-assembly and strong metal-support interaction (SMSI). Aluminosilicate in the mesostructured wall is an SMSI agent and charge transfer from Pt to the aluminosilicate suppresses the sintering of intermetallic nanoparticles. Intermetallic PtPb and Pt₃Co on carbon-based mesoporous supports are synthesized, and their particle sizes are below 5 nm even at high loading. The PtPb catalyst shows 15 times higher mass activity for formic acid oxidation than Pt/C, and the Pt₃Co catalyst shows 3.25 times higher mass activity for oxygen reduction than Pt/C. This procedure can be extended to synthesize various heterogenous catalysts that require high temperature for synthesis or to operate.