Enhancing Ni/Co Activity by Neighboring Pt Atoms in NiCoP/MXene Electrocatalyst for Alkaline Hydrogen Evolution.
Angew Chem Int Ed Engl
; 63(20): e202401819, 2024 May 13.
Article
en En
| MEDLINE
| ID: mdl-38409658
ABSTRACT
Density functional theory (DFT) calculations demonstrate neighboring Pt atoms can enhance the metal activity of NiCoP for hydrogen evolution reaction (HER). However, it remains a great challenge to link Pt and NiCoP. Herein, we introduced curvature of bowl-like structure to construct Pt/NiCoP interface by adding a minimal 1 -molar-ratio Pt. The as-prepared sample only requires an overpotential of 26.5 and 181.6â
mV to accordingly achieve the current density of 10 and 500â
mA cm-2 in 1â
M KOH. The water dissociation energy barrier (Ea) has a ~43 % decrease compared with NiCoP counterpart. It also shows an ultrahigh stability with a small degradation rate of 10.6â
µV h-1 at harsh conditions (500â
mA cm-2 and 50 °C) after 3000â
hrs. X-ray photoelectron spectroscopy (XPS), soft X-ray absorption spectroscopy (sXAS), and X-ray absorption fine structure (XAFS) verify the interface electron transfer lowers the valence state of Co/Ni and activates them. DFT calculations also confirm the catalytic transition step of NiCoP can change from Heyrovsky (2.71â
eV) to Tafel step (0.51â
eV) in the neighborhood of Pt, in accord with the result of the improved Hads at the interface disclosed by in situ electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM) tests.
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