Composition adjustment of PtCoCu alloy assemblies towards improved hydrogen evolution and methanol oxidation reaction

Binary PtCo, PtCu and ternary PtCoCu alloys with different surface element distributions were prepared to study the effect of composition on electrocatalytic hydrogen evolution reaction (HER) and methanol oxidation reaction (MOR). A one-pot method was used to synthesize self-assembled alloy nanocrystals in one step. By adjusting the composition of synthesized alloys, their properties were optimized. The changes of morphology and property of the alloys after adding Cu were discussed. The HER and MOR properties of alloys were affected by the composition. Especially, the ternary alloy revealed better properties than that of the binary alloy. The starting potential of PtCoCu alloy in HER reaction under visible light is 14 mV and the overpotential under 10 mA cm −1 is 44 mV, which revealed excellent cycle stability. The current density at 0.7 V for MOR reaction can reach 4.2 mA cm −1 . This is ascribed to the composition of alloy. Cu in alloys resulted in plasma-induced effective electron transfer. This result provides a feasible strategy for the design of effective multifunctional electrocatalysts. • Binary and ternary self-assembled nanoparticles were successfully prepared. • PtCoCu and PtCu alloys have photo-assisted electrocatalytic properties. • The Cu element in the alloy can induce rapid electron transfer under visible light.