Controlled Photocatalytic Oxidation of Methane to Methanol through Surface Modification of Beta Zeolites

Abstract

The selective oxidation of methane to methanol is achieved by means of a photocatalytic process. For this purpose, designed Bi- and V-containing beta zeolites prepared by incipient wetness impregnation have been used under different test conditions. While the zeolite proves to be photoactive under UVC irradiation toward the total oxidation process, the formation of V2O5 on the surface is an effective alternative for modifying the acid–base surface properties, thus significantly decreasing the undesired CO2 formation. At the same time the zeolite framework serves as a scaffold for increasing the surface area and distribution of the metal oxide. Additionally, the addition of low Bi amount favors the formation of a BiVO4/V2O5 heterojunction, which acts as a visible light photocatalyst while at the same leading to total selectivity to methanol at the expense of ethylene formation.

Recent Advances in Heterogeneous Photo‐Driven Oxidation of Organic Molecules by Reactive Oxygen Species

“…[38] The construction of heterojunctions is also an effective means for improving the photocatalytic efficiency. Murcia-López et al [39] loaded V 2 O 5 and BiVO 4 on an Htype BEA zeolite (HBEA), which increased the specific surface area of the catalyst and led to the production of methanol. Recently, Song et al [40] reported that ZnO loaded with metals (Pt, Pd, Au, or Ag) enables the direct oxidation of methane to methanol and formaldehyde using only molecular oxygen as the oxidant.…”

Highly selective oxidation of methane to methanol at ambient conditions by titanium dioxide-supported iron species

“…Despite such potential, there are few reports of photocatalytic processes for CH4 transformation under ambient conditions and with satisfactory selectivity for methanol production. [34][35][36][37] Herein we report metal oxide species anchored on TiO2 as a photon promoted catalysts for methane conversion to methanol in the presence of H2O2 at room temperature and 1 bar gas pressure. Furthermore, we show that iron oxide species are the most active for this process compared with other noble metals or transition metal clusters.…”

Direct functionalization of methane into ethanol over copper modified polymeric carbon nitride via photocatalysis

“…WO 3 has been a classic material in this field supplying hydroxyl radical (·OH) through H 2 O oxidation to turn methane into methanol 10–13 . In addition to WO 3 , bismuth-based compounds such as BiVO 4 and Bi 2 WO 6 have also been estimated 14 , while reports of V containing zeolites have emerged recently about tuning the surface acid−base properties to a better methanol selectivity 15,16 . In these researches, the highest methanol production rate is 67.5 μmol g cat −1 h −1 from WO 3 by using electron scavenger 12 , which is still far from satisfaction.…”