Abstract
Titanium nitride (TiN) inverse opal structure was fabricated by atomic layer deposition (ALD) as a support for Pt catalyst for proton exchange membrane fuel cell (PEMFC) by atomic layer deposition (ALD). Polystyrene (PS) spheres were coated in multilayers on carbon paper by spin-coating as a template. The surface area can be increased by using smaller size of spheres and by increasing the thickness of PS multilayers. The proportion of micropores can also be adjusted by using spheres in different diameters. Titanium dioxide (TiO2) thin film was then deposited on PS sphere multilayers by ALD. Titanium nitride inverse opal structure was obtained by direct nitridation of TiO2 inverse opal structure in flowing ammonia atmosphere at 800 ˚C for 1 h. Platinum nanoparticles were then deposited on TiN inverse opal structure by ALD as well, and a uniform coverage down to 10 µm of depth was achieved. The particle size and loading could be controlled by the cycle number of ALD. Because of self-limiting reactions of ALD, the Pt loading can be increased by lowering the sphere size and increasing the thickness of TiN inverse opal layers. The performance of PEMFC using Pt/TiN inverse opals as electrodes was evaluated by a home-made PEMFC test station. The home-made electrodes showed lower power capacities but showed higher specific power densities and thus better utilization efficiency of Pt compared with that using commercial E-Tek electrodes.