Polyelectrolyte-Microgel-Templated Nickel–Nickel Oxide Nanoparticles for Oxidation Catalysis with o-Phenylenediamine as a Model Substrate

Using electrostatic nanotemplating, a ternary nanostructured system consisting of a poly(styrenesulfonate) microgel and nickel–nickel oxide hybrid particles (PSS-Ni0/NiO) was designed for aqueous catalytic application. The microgel template influences the morphology and increases the stability of the Ni0/NiO catalyst nanoparticles. Spherical Ni0/NiO nanoparticles are contained within the microgel, with additional smaller nanoparticles on its outside. The catalytic oxidation of o-phenylenediamine serves as a model reaction for oxidation catalysis, while the ternary particles may be applied for hydrogen oxidation in fuel cells and as chemical sensors. For structure and performance, the loading ratio and the Ni0-to-NiO ratio are key.