Ag–M (M: Ni, Co, Cu, Fe) bimetal catalysts prepared by galvanic deposition method for CO oxidation

Ag–M (M: Fe, Co, Ni, Cu) bimetal catalysts supported on SiO2 were prepared by galvanic deposition (GD) method. HAADF-STEM observation and EDX elemental mapping showed that Ag was successfully introduced on Fe, Co, Ni, and Cu particles using the GD method. Ag–Fe, Ag–Co, and Ag–Cu catalysts showed Janus structure that is Ag nanoparticles (NPs) on the 3d metals. On the other hand, Ag–Ni catalyst showed core–shell like structure composed of small Ag NPs (<10 nm) or thin layer on Ni particles. The catalytic activities of Ag–M bimetal catalysts were evaluated by CO oxidation reaction. All Ag–M bimetal catalysts showed higher catalytic activities than Fe, Co, Ni, Cu, and Ag mono-metal catalysts. In particular, Ag–Ni bimetal catalyst having core–shell like structure showed remarkable enhancement of the catalytic activity.