Suppression of Carbon Monoxide Poisoning in Proton Exchange Membrane Fuel Cells via Gold Nanoparticle/Titania Ultrathin Film Heterogeneous Catalysts

Titania (TiO2)-supported gold (Au) nanoparticles (NPs) have long been considered as a promising solution for carbon monoxide (CO) poisoning in proton exchange membrane fuel cells (PEMFCs) as they can efficiently catalyze CO oxidation reaction. Nevertheless, the actual application in functioning PEMFCs has been rarely reported primarily due to the challenges of synthesizing and incorporating the oxidation catalyst in manners compatible with the structure and fabrication of PEMFCs. Here we successfully incorporate the Au NPs/TiO2 catalyst into PEMFCs and demonstrate an excellent CO elimination function, improving the performance and CO tolerance of PEMFCs; we combine an ultrathin TiO2 layer (<1 nm) deposited on a Nafion membrane via the low-temperature atomic layer deposition (ALD) and a monolayer of Au NPs assembled on the top of the ultrathin TiO2 using the Langmuir–Blodgett method. An over 30% enhanced maximum power output is achieved under the presence of a trace amount of CO. Even under highly concentrated CO (0.1%), a less than 10% performance decrease occurs with the incorporation of Au NPs/TiO2, in contrast to a nearly 70% performance decrease observed in the control device. The results represent the first experimental implementation of Au NPs/TiO2 catalysts in PEMFCs and the confirmation of their effectiveness for mitigating the CO poisoning effect.