Ultra-thin platinum catalytic electrodes fabricated by atomic layer deposition

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Noble metal catalysts, particularly platinum (Pt), are essential components in low-temperature fuel cells but contribute significantly to overall costs.
• Reducing the loading of these expensive noble metals is crucial for making fuel cell technology more economically viable.

Purpose of the Study:

• To investigate the efficacy of ultra-thin platinum (Pt) cathode catalyst layers fabricated by atomic layer deposition (ALD) for low-temperature solid oxide fuel cells.
• To determine the optimal Pt loading and thickness using ALD for high-performance fuel cell electrodes.

Main Methods:

• Fabrication of ultra-thin platinum (Pt) catalyst layers (approximately 10 nm) using atomic layer deposition (ALD).
• Testing of the ALD Pt layers as cathode electrodes in low-temperature solid oxide fuel cells.
• Characterization using Transmission Electron Microscopy (TEM) to analyze morphology and triple-phase boundary (TPB) density.

Main Results:

• A 10 nm thick ALD Pt layer, corresponding to a Pt loading of only 0.02 mg cm⁻², was sufficient for a functional catalytic cathode.
• The performance of the ALD Pt cathode was comparable to that of a much thicker (80 nm) sputtered Pt cathode.
• TEM analysis confirmed that the optimized ALD cycles resulted in contiguous Pt films with high triple-phase boundary (TPB) density.

Conclusions:

• Atomic layer deposition (ALD) enables significant reduction in platinum (Pt) loading for fuel cell cathodes, thereby lowering costs.
• The developed ALD Pt fabrication method is suitable for high-performance fuel cells, including those with complex three-dimensional structures.