Synthesis of noble/non-noble metal alloy nanostructures via an active-hydrogen-involved interfacial reduction strategy

Traditional solution-phase synthesis of noble/non-noble metal alloy nanocrystals lacks control over metal co-reduction due to the difference in reduction potentials. As a result, these synthetic routes lead to constrained compositional space. To address this problem, we have developed an active-hydrogen (H*)-involved interfacial reduction method for the synthesis of alloy nanostructures. The introduction of HNO 2 into the reaction generates H* at the metal seed/solution interface, creating a highly reducing environment. Metal reduction, therefore, migrates from the solution phase to the interface, and H*, as a strong reducing agent, can negate the effect of the reduction potential differences of metal salts, leading to their effective co-reduction. We demonstrate the synthesis of a library of Pt–M alloy nanoshells (M = Fe, Co, Ni, Ga, In, Sn, Pb, Bi) on palladium octahedral cores with precise compositional control, enabling screening of the materials as catalysts for the hydrogen evolution reaction. This strategy paves a way for noble/non-noble metal alloy nanostructures with superior synthetic control for a broad range of applications.