An electrode material which may be used in an electrochemical cell used to convert carbon dioxide into useful products, such as synthetic fuel. The electrode material may comprise nano-sized core-shell catalyst (i.e., core-shell nanoparticles, or CSNs) having a catalytic core component encompassed by one or more outer shells, wherein at least one of the outer shells has a mesoporous structure. Electrochemical cells, electrochemical cell electrodes, and methods of making CSNs are also provided.