Moreover, the formate species, derived from the chemically adsorbed HCHO, could be directly converted to CO2 and H2O by reacting with a neighbouring surface hydroxyl over noble metal sites.7, 27, 28 Due to the important role of the surface hydroxyls in the HCHO complete oxidation, the physi-chemical properties of the surface hydroxyls nearby the noble metal sites could be a dominating factor to determine the performances of the noble metal catalysts.