Synthesis of binary metal–metal oxide core-shell nanoparticles via surfactant-free intercation redox reactions

Surfactant-free one-step redox reactions between two types of metal cations enable the synthesis of core-shell nanoparticles without sophisticated control. The reduced noble metal cations form a solid core, and the transition metal cations dissolved upon oxidation induce the subsequent formation of a metal oxide shell. Various nanostructures are obtained from the combination of reduction-preferring Au³⁺, Pd²⁺, Pt²⁺, Rh³⁺, and Ir³⁺ cations, and oxidation-preferring Ti³⁺, Mo³⁺, V²⁺, and V³⁺ cations. Among the synthesized core-shell nanoparticles, Au–M (M = Ti, Mo, and V) is selected for the photodegradation tests at 365 and 808 nm.