[email protected] monolayer catalysts have dual advantages in electrocatalysis, cost of the catalyst is minimized by depositing expensive metal as a monolayer shell and the catalytic activity can be enhanced by selecting an appropriate core metal. In this communication, a novel chemically assisted underpotential deposition process to fabricate [email protected] monolayer nanoparticles in bulk scale has been introduced. Ag(shell)@Pd(core)/C nanoparticles have been prepared by this electroless underpotential deposition method. The thickness of the Ag shell has been calculated as one atomic layer from XPS analysis. Core-shell structure of nanoparticles has been confirmed by STEM characterization. Further, Pt(shell)@Pd(core)/C nanoparticles have been engineered from [email protected]/C nanoparticles by Galvanic replacement of Ag by Pt. This [email protected]/C electrocatalyst has been tested for formic acid oxidation.