Atomic Layer Deposition of Cobalt Phosphide for Efficient Water Splitting

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Transition-metal phosphides (TMPs) are crucial catalysts for hydrogen evolution reactions.
• Traditional methods for TMP synthesis often lack control over film thickness and uniformity.
• Atomic Layer Deposition (ALD) offers precise control over thin film growth.

Purpose of the Study:

• To report for the first time the synthesis of ultrathin cobalt-phosphide (Co-P) films using ALD.
• To investigate the structural and electrochemical properties of ALD-grown Co-P films.
• To demonstrate the potential of ALD for conformal coating of TMPs on complex architectures.

Main Methods:

• Ultrathin Co-P films were deposited using a novel ALD process with PH3 plasma and an H2 plasma post-treatment.
• The ALD process involved self-limited layer-by-layer growth for high purity and smoothness.
• Co-P films were characterized for their structural, morphological, and electrochemical properties.

Main Results:

• ALD enabled the deposition of highly pure and smooth ultrathin Co-P films.
• ALD-grown Co-P films demonstrated superior electrochemical and photoelectrochemical hydrogen evolution reaction (HER) activities compared to conventionally prepared films.
• Conformal coating of ultrathin Co-P films on periodic trenches was successfully achieved.

Conclusions:

• ALD is a viable and effective method for synthesizing high-performance ultrathin Co-P films for HER catalysis.
• The developed ALD process offers advantages in terms of purity, smoothness, and catalytic activity.
• This ALD approach holds significant promise for the fabrication of TMP-based electrocatalysts on complex 3D nanostructures.