Low Pt-content ternary PtNiCu nanoparticles with hollow interiors and accessible surfaces as enhanced multifunctional electrocatalysts.

Developing highly active and durable electrocatalysts with low levels of Pt content toward some crucial reactions including oxygen reduction reaction, hydrogen evolution reaction and methanol oxidation reaction in an acidic electrolyte environment are desirable but still an open challenge for clean and efficient energy conversion. Herein, we present a facile route to synthesize low Pt-content ternary PtNiCu nanostructures with hollow interior and accessible surfaces (H-PtNiCu-AAT NPs) as enhanced multifunctional electrocatalysts. The galvanic replacement reaction and atomic diffusion between in situ preformed CuNi nanocrystals and Pt species should be responsible for the formation of hollow PtNiCu NPs. Continuous activation by acid picking and annealing treatments were performed to leach out the excessive Cu and Ni on the surfaces and to enrich Pt-content on the surface. H-PtNiCu-AAT NPs exhibit excellent activity and durability toward HER, ORR and MOR due to the rational integration of multiple structural advantages. Strikingly, the mass activity and specific activity of H-PtNiCu-AAT NPs (0.977 A mg-1Pt and 1.458 mA cm-2) is 7.1 and 6.9 times higher than that of commercial Pt/C (0.138 A mg-1Pt and 0.212 mA cm-2), respectively. This present work provides an efficient strategy for the design of low Pt-content trimetallic electrocatalysts with excellent activity and durability.