Surface functionalization of Pt nanoparticles with metal chlorides for bifunctional CO oxidation

Incorporation of a metal oxide or hydroxide species into Pt-based electrocatalysts has been shown to lower the overpotential required to oxidatively remove carbon monoxide from the catalyst surface, a reaction that is critical to preventing catalyst poisoning and deactivation in fuel cell devices. In this work, we report a general synthetic method toward Pt-metal oxide composite nanoparticles via the adsorption of metal halide ligands onto 1-2 nm colloidal Pt nanoparticles. Pt-metal oxide composite nanoparticles spanning across the first-row transition metals and post-transition metals are synthesized and characterized with transmission electron microscopy and energy dispersive X-ray scattering. CO stripping and steady-state CO oxidation experiments reveal that Mn, Fe, Co, Ni, and In oxides are capable of participating in the catalysis as a bifunctional partner and reduce the overpotential required for CO electrooxidation by similar to 200 mV relative to pure Pt. (C) 2019 Elsevier Ltd. All rights reserved.