CoP‐Doped MOF‐Based Electrocatalyst for pH‐Universal Hydrogen Evolution Reaction

Abstract

Although electrocatalysts based on transition metal phosphides (TMPs) with cationic/anionic doping have been widely studied for hydrogen evolution reaction (HER), the origin of performance enhancement still remains elusive mainly due to the random dispersion of dopants. Herein, we report a controllable partial phosphorization strategy to generate CoP species within the Co-based metal-organic framework (Co-MOF). Density functional theory calculations and experimental results reveal that the electron transfer from CoP to Co-MOF through N-P/N-Co bonds could lead to the optimized adsorption energy of H₂ O (ΔG <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mrow></mml:mrow> <mml:mrow><mml:mi>H</mml:mi> <mml:msub><mml:mrow></mml:mrow> <mml:mn>2</mml:mn></mml:msub> <mml:mi>O</mml:mi> <mml:mo>*</mml:mo></mml:mrow> </mml:msub> </mml:math> ) and hydrogen (ΔG_H* ), which, together with the unique porous structure of Co-MOF, contributes to the remarkable HER performance with an overpotential of 49 mV at a current density of 10 mA cm^-2 in 1 m phosphate buffer solution (PBS, pH 7.0). The excellent catalytic performance exceeds almost all the documented TMP-based and non-noble-metal-based electrocatalysts. In addition, the CoP/Co-MOF hybrid also displays Pt-like performance in 0.5 m H₂ SO₄ and 1 m KOH, with the overpotentials of 27 and 34 mV, respectively, at a current density of 10 mA cm^-2 .