A nanoporous Pt particles-modified Ti (nanoPt/Ti) electrode was prepared through a simple hydrothermal method using aqueous H 2 PtCl 6 as a precursor and formaldehyde as a reduction agent. The nanoPt/Ti electrode was then modified with limited amounts of tin particles generated by cyclic potential scans in the range of formaldehyde oxidation can be illustrated by a so-called bifunctional mechanism which is involved in the oxidation of poisoning adsorbed CO species via the surface reaction with OH adsorbed on neighboring Sn sites.