Photocatalytic oxidation of methanol to methyl formate in liquid phase over supported silver catalysts

• Supported silver catalysts were active for selective oxidation of methanol to methyl formate in liquid phase by oxygen.
• Silver nanoparticles on P25 promoted reaction by removing electrons from surface of titania.
• The SPR of silver nanoparticles on silica played a role for methyl formate formation.
• P25 and silica were negative for the formation of methyl formate under UV irradiation.
• UV light was slightly active for the formation of methyl formate.

The selective oxidation of methanol to methyl formate by oxygen in the liquid phase under UV irradiation was investigated on supported silver catalysts. The catalysts exhibited high performance in the formation of methyl formate. The silver nanoparticles on P25 promoted the reaction through removing the photoexcited electrons from the surface of titania to extend the hole–electron lifetime. The surface plasma resonance (SPR) of the silver nanoparticles on silica was responsible for the formation of methyl formate. UV light itself was slightly active to the formation of methyl formate.

The SPR effect of silver nanoparticles was observed on the UV–vis absorption spectra of silver catalysts supported on P25 and silica. The absorption band induced by SPR of silver nanoparticles on P25 was peaking at 470 nm and that on silica was peaking at 380 nm. The SPR of silver particles on silica played a role for the formation of methyl formate and that on P25 exhibited little relation to methyl formate formation. Silver nanoparticles on P25 played a role for removing the photoexcited electrons from the surface of titania and thus promoted the reaction.Figure optionsDownload as PowerPoint slide