Atomic Layer Deposition of Pd: Schottky Junction Construction on CoP-Co₂P for Efficient Hydrogen Evolution

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Cobalt phosphide (CoP)-based materials are promising for alkaline hydrogen evolution reactions (HER) but suffer from instability.
• Noble metal catalysts are effective but expensive for HER.

Purpose of the Study:

• To engineer a stable and efficient cobalt phosphide electrocatalyst for HER using atomic layer deposition (ALD).
• To investigate the mechanism behind enhanced catalytic activity and durability.

Main Methods:

• Fabrication of a Pd@CoP-Co2P Schottky junction on nickel foam (NF) via ALD.
• Electrochemical characterization of HER and oxygen evolution reaction (OER) performance.
• X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) for mechanistic studies.

Main Results:

• Achieved ultralow palladium loading (0.06 wt %) with significantly reduced HER overpotential (55 mV at 10 mA cm-2) and enhanced stability (300 h).
• Demonstrated remarkable bifunctional activity with OER performance (177 mV at 10 mA cm-2) and 300 h stability.
• XPS and DFT revealed that the Pd Schottky junction modulates the electronic structure of CoP-Co2P, optimizing the Gibbs free energy and preventing degradation.

Conclusions:

• ALD is a powerful technique for creating durable transition metal phosphide electrocatalysts through interface engineering.
• The Pd@CoP-Co2P Schottky junction effectively enhances HER and OER performance and stability.
• The findings pave the way for developing advanced electrocatalysts for clean energy applications.