Sparkling Synergy: Enhancing Hydrogen Evolution with a Mesoporous CoP/FeP Interface

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrocatalyst surface and interface engineering are crucial for reaction kinetics.
• Developing efficient electrocatalysts is key for energy conversion technologies like hydrogen production.

Purpose of the Study:

• To synthesize and characterize a novel cobalt monophosphide and iron monophosphide (CoP/FeP) electrocatalyst with an effective solid interface.
• To evaluate the hydrogen evolution reaction (HER) performance of the CoP/FeP electrode compared to individual CoP and FeP.
• To establish a relationship between theoretical calculations and experimental HER activity.

Main Methods:

• Synthesis of mesoporous CoP/FeP via phosphidization of mesoporous CoFe2O4.
• Electrochemical characterization including overpotential, exchange current density, Tafel slopes, electrochemical impedance spectroscopy, and turnover frequency.
• Density functional theory (DFT) calculations to determine differential hydrogen adsorption energy and Gibbs free energy change.

Main Results:

• CoP/FeP exhibited superior HER performance with an overpotential of 98 mV vs. 220 mV (FeP) and 265 mV (CoP) at 10 mA cm−2.
• CoP/FeP demonstrated enhanced redox properties, faster kinetics, reduced impedance, and superior charge transport.
• Calculations revealed that the CoP-rich CoP/FeP surface has the highest catalytic potential for HER.

Conclusions:

• The engineered CoP/FeP electrocatalyst with a solid interface and mesoporous surface significantly enhances HER performance and durability.
• The synergistic effect between CoP and FeP contributes to improved catalytic activity and charge transport.
• The study establishes a strong correlation between theoretical predictions and experimental results for HER electrocatalysis.