Experimental and Theoretical Insights into Enhanced Hydrogen Evolution over PtCo Nanoalloys Anchored on a Nitrogen-Doped Carbon Matrix

The identification of synergistic effect of Pt-based alloys on hydrogen evolution reaction (HER) requires a combination of experimental studies and theoretical calculations. Here, we present the construction of uniform PtCo nanoparticles grown on N-doped carbon frameworks via pyrolyzing Pt and Co ions adsorbed polyaniline, whereby the nanostructure of the nanoalloys can be effectively tuned by controlling the calcination temperature. As-prepared PtCo@NC-900 shows the optimal HER performance in 0.5 M H2SO4, resulting in a high mass activity of 4.31 A mgPt –1 and excellent operation durability, which far exceeds that of commercial 20 wt % Pt/C (0.30 A mgPt –1). Density functional theory calculations further reveal that the improved HER activity on PtCo(111) is originated from the strong electronic interaction between Pt and Co with favorable electron transfer, allowing for a more suitable binding strength for hydrogen (i.e., ΔG *H = −0.164 eV) compared with that of pristine Pt(111) (−0.287 eV).