CoP-Doped MOF-Based Electrocatalyst for pH-Universal Hydrogen Evolution Reaction.

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Transition metal phosphides (TMPs) are widely studied for hydrogen evolution reaction (HER) electrocatalysis.
• The precise mechanism of performance enhancement in doped TMPs remains unclear due to random dopant distribution.

Purpose of the Study:

• To develop a controllable partial phosphorization strategy for generating cobalt phosphide (CoP) species within a cobalt-based metal-organic framework (Co-MOF).
• To elucidate the origin of performance enhancement in the synthesized CoP/Co-MOF electrocatalyst for HER.

Main Methods:

• Controllable partial phosphorization of Co-MOF to create CoP species.
• Density functional theory (DFT) calculations to investigate electronic structure and adsorption energies.
• Electrochemical characterization of HER performance in various electrolytes (PBS, H2SO4, KOH).

Main Results:

• The CoP/Co-MOF hybrid catalyst demonstrated excellent HER performance with a low overpotential of 49 mV at 10 mA cm⁻² in neutral PBS (pH 7.0).
• DFT calculations and experimental results confirmed electron transfer from CoP to Co-MOF, optimizing H2O and H* adsorption energies.
• The catalyst exhibited Pt-like performance in acidic (0.5 M H2SO4) and alkaline (1 M KOH) media, with overpotentials of 27 mV and 34 mV, respectively.

Conclusions:

• The controllable partial phosphorization strategy effectively generates highly active CoP species within a Co-MOF structure.
• The synergistic electron transfer and unique porous architecture of CoP/Co-MOF significantly boost HER electrocatalytic activity.
• CoP/Co-MOF represents a promising non-noble metal electrocatalyst for efficient hydrogen production across a wide pH range.