Photocatalytic oxidation of methanol using porous Au/WO3 and visible light

作者：DePuccio Daniel P; Landry Christopher C^*

来源：Catalysis Science & Technology, 2016, 6(20): 7512-7520.

DOI：10.1039/c6cy01449f

Porous tungsten oxide (WO3) visible light photocatalysts were prepared via hard templating using mesoporous silica (SiO2). Nitrogen physisorption and powder XRD confirmed the greater surface area and smaller nanocrystallites of porous WO3 compared to bulk WO3 ((B)-WO3). Sonochemical deposition of gold nanoparticles (Au NPs) was used to further modify the porous WO3 catalyst. The photocatalytic oxidation of methanol (MeOH) under continuous flow conditions was used to evaluate the activity of the porous photocatalysts. Porous WO3 exhibited significantly higher MeOH oxidation activity compared to (B)-WO3 due to its increased surface area. In separate experiments, WO3 and SiO2-supported Au NPs were highly selective MeOH photooxidation catalysts for the production of formaldehyde (HCHO, 60%) and methyl formate (MF), respectively. This indicated that two different photocatalytic mechanisms, namely band gap excitation (WO3) and surface plasmon resonance (SPR, Au NPs), were responsible for the two different oxidation products. When combined with Au NPs, WO3 showed higher rates of MeOH oxidation compared to pure WO3 due to more efficient electron and hole separation. In addition, the reduction of O-2 to H2O by photoexcited electrons was more efficient in the presence of Au NPs compared to pure WO3. At higher Au NP loadings, however, selective oxidation of MeOH decreased at the expense of greater CO2 formation due to increased oxidation activity of the combined WO3-Au catalyst.

• 出版日期2016