Durability of Colloidally Stabilized Supported Nickel and Nickel Platinum Nanoparticles during Redox-Cycling

We report on the oxidation and reduction behaviorof colloidally stabilized Ni nanoparticles and Pt@NiPt core−shellnanoparticles with a platinum content of 4%. Thin films of bothnanoparticle systems were deposited on yttria-stabilized zirconiasubstrates by spin-coating. Oxidation−reduction cycles were usedto remove oxides and organics and obtain metallic particles. Thecycling conditions necessary to clean and reduce Pt@NiPt core−shell nanoparticles were milder than for the Ni nanoparticles,which also needed several cycles to burn off residual organics.During cycling, the Ni nanoparticles lost their initially epitaxialrelationship with the substrate and adopted a random orientation,while no epitaxial orientation was observable for the core−shellnanoparticles. Reasons for this are discussed together with theinfluence of platinum on Ni reduction. The Ni and Pt@NiPt nanoparticles sintered during the process but retained crystallinedomain diameters close to the original particle diameters. Our results show that colloidally stabilized nanoparticles can be transferredonto a technologically relevant substrate and be reduced to metallic nanoparticles. The fabrication and final structures are discussedas a feasible route to realize solid oxide fuel cell anodes with tailored nickel particle diamete