Growth-Front Monolayer Plating of Precious Metals through Insulating Mesoporous Supports

Monolayers of precious metals are deposited within the pores of insulating mesoporous membranes via a new electrochemical underpotential deposition growth front mechanism.   A gold electrode is evaporation deposited onto one membrane face and a monolayer of copper is underpotentially deposited through the membrane and to the top surface, followed by spontaneous galvanic replacement of copper by platinum or iridium. Detection of precious metal on the opposite membrane face via XPS surface analysis and quantification of areal density by ICP-IES demonstrates a novel copper monolayer growth front plating mechanism through the pores. Catalytic water splitting for hydrogen generation is demonstrated for applications including polymer electrolyte membrane fuel cells, hydrogen generation, flow battery energy storage, and electrocatalytic conversions.