In Situ Generation of Pt2Co3 Nano-Alloys in Porous N-Doped Carbon for Highly Efficient Electrocatalytic Hydrogen Evolution

Platinum (Pt) catalysts are the state-of-the-art electrocatalysts for hydrogen evolution reaction (HER), but it is still a challenge to improve the utilization efficiency and stability of Pt-based catalysts. Herein, Pt2Co3 nano-alloys anchored on the surface of the N-doped carbon support are precisely synthesized via metal complex-controlled pyrolysis. Benefiting from the formation and exposure of the bimetallic nano-alloys, the optimal Pt2Co3/NC-950 electrocatalyst exhibits an extraordinary HER catalytic activity and stability. To achieve a current density of 10 mA cm(-2), the Pt2Co3/NC-950 electrocatalyst requires small overpotentials of 12 mV in both acidic and alkaline media with small Tafel slopes of 6 mV dec(-1) and 24 mV dec(-1) in 0.5 M H2SO4 and 1 M KOH, respectively, which is superior to the commercialized Pt/C catalyst. Additionally, the much higher turnover frequencies and the larger electrochemical surface areas of Pt2Co3/NC-950 further reveal its superior catalytic active sites. Based on theoretical calculations, the outstanding HER activity is found to be attributed to the synergic effect of the Pt and Co components that optimizes the adsorption Gibbs free energy of hydrogen atom and accelerates water dissociation in alkaline media.