Atomic Layer Deposited Tantalum Oxide to Anchor Pt/C for Highly Stable Catalyst in PEMFCs
Tantalum oxide (TaOx) nanoparticles (NPs) are deposited on commercial Pt/C catalyst by an area-selective atomic layer deposition (ALD) approach to enhance the stability of catalyst in proton exchange membrane fuel cells (PEMFCs). Due to the application of a blocking agent for protecting the Pt surface, TaOx particles are selectively nucleated and grown around Pt NPs. The TaOx loading on Pt/C surface could be controlled precisely by the numbers of ALD cycles. When deposited on the Pt/C surface with 35 ALD cycles, the TaOx-anchored Pt NPs forming an excellent triple-junction structure of TaOx-Pt-Carbon. The electrochemical durability tests indicated that the TaOx-anchored Pt/C catalyst showed comparable catalytic activity and superior long-term stability compared to Pt/C. Moreover, the long-term stability test in membrane electrode assembly (MEA) indicated very low power density loss (12%) after 120 h accelerate durability test. The significantly enhanced catalyst stability during PEMFCs operation is due to the anchoring effect of TaOx via strong metal-oxide-support interactions. This strategy shows great potential for developing the highly stable catalysts for PEMFCs.