Turing Charge Distribution via S-Doping of Porous CoMoP₂ for Efficient Overall Water Splitting Electrocatalysis

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Efficient green hydrogen production relies on cost-effective bifunctional electrocatalysts for overall water splitting.
• Developing non-noble metal catalysts with high activity and stability is crucial for advancing water electrolysis.

Purpose of the Study:

• To synthesize and characterize a novel sulfur-doped porous cobalt molybdenum phosphide catalyst (S-CoMoP/NF) on nickel foam.
• To evaluate the bifunctional electrocatalytic activity of S-CoMoP/NF for hydrogen and oxygen evolution reactions.
• To elucidate the role of sulfur doping in modulating the electronic structure and catalytic performance using DFT calculations.

Main Methods:

• Step-by-step hydrothermal synthesis of S-CoMoP/NF.
• Extensive physicochemical characterization (e.g., XRD, SEM, TEM, XPS).
• Electrochemical testing in 1.0 M KOH for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER).
• Density functional theory (DFT) calculations to understand doping effects on electronic structure and adsorption.

Main Results:

• S-CoMoP/NF exhibits excellent bifunctional activity with low overpotentials: 191 mV for HER and 331 mV for OER at 100 mA cm^-2.
• Sulfur doping effectively tunes the electronic structure and optimizes adsorption properties, enhancing catalytic kinetics.
• The S-CoMoP/NF||S-CoMoP/NF electrolyzer operates at 1.82 V for 100 mA cm^-2 and shows stable performance for 80 hours.

Conclusions:

• Sulfur doping is an effective strategy to enhance the performance of non-noble bifunctional electrocatalysts for water splitting.
• S-CoMoP/NF presents a promising, economical, and highly efficient catalyst for green hydrogen production.
• Anionic doping significantly modulates charge distribution, leading to accelerated catalytic kinetics and improved water decomposition efficiency.