Abstract
Room-temperature oxidation over supported noble metals provides a feasible approach to eliminating formaldehyde (HCHO) from indoor air. Oxygen activation by noble metals such as gold and platinum plays a key role in achieving complete HCHO oxidation, but it is unclear how different noble metals function synergistically toward oxygen activation. Here, the synergistic mechanisms of Pt and Au nanoparticles (NPs) coloaded on TiO2 in catalytic HCHO oxidation are elucidated. Strikingly, approximate to 0.08% doping of Pt can dramatically improve the catalytic activity of 0.9% Au/TiO2. The surface oxygen species of TiO2 jointly activated by Au and Pt NPs can rapidly transform HCHO to dioxymethylene surface species, while negatively charged Pt NPs can efficiently adsorb and activate molecular oxygen to oxidize the dioxymethylene into formate, which is further completely oxidized. This synergy enables efficient HCHO oxidation at surface sites between adjacent Pt and Au NPs.