Mechanism of photocatalytic oxidation of formaldehyde

The adsorption state of reactants, free radical intermediates and the reaction mechanism have been studied by means of temperature programmed description (TPD), electron spin resonance (ESR) and spin traping-ESR in the photocatalytic oxidation of formaldehyde. The results showed that O-2 adsorbed on the surface of photocatalyst could be reduced to .O-2(-) by photogenerated electrons and H2O could be oxidized to . OH by holes, Both free radicals are active oxidants in the reaction of photocatalytic oxidation of HCHO. The photocatalytic oxidation of HCHO carried out with two steps, Firstly, HCHO was oxidized into HCOOH, then HCOOH converted into final product of CO2 and H2O.