Bimetallic Ni and Pt single atoms anchored on nitrogen-phosphorus doped porous carbon fibers to achieve significant electrocatalytic hydrogen evolution

The commercial application of water electrolysis for hydrogen production requires the development of low precious metal catalysts with a high crustal abundance. One feasible strategy is to utilize bimetallic catalysts composed of both transition and precious metals. In this study, a novel N/P-doped Ni/Pt bimetallic catalyst is developed (NiPt@C-NP, 3.68 % Ni, 0.2 % Pt) using polyacrylonitrile fibers as an inexpensive carbon source for catalyst support. Due to strong anchoring from the N and P heteroatoms, the nickel and platinum species are mono-atomically dispersed throughout the catalyst. Under acidic conditions, NiPt@C-NP exhibits a hydrogen evolution overpotential of 89 mV (10 mA cm-2), whereas an unsupported platinum catalyst gives an overpotential of 302 mV. The mass activity of Pt in NiPt@C-NP reaches 36.17 A mgPt- 1, which is 33 times higher than 20 % Pt/C (1.07 A mgPt-1). Density functional theory (DFT) calculations reveal that synergistic interactions between Ni and Pt significantly increase the density of state near the Fermi level of NiPt@C-NP, resulting in a reduced bandgap and an enhanced charge transfer capability. Furthermore, the Gibbs free energy at the Pt and Ni sites is - 0.25 and - 0.63 eV, respectively, indicating fast reaction kinetics.