Facile construction of leaf-like WO3 nanoflakes decorated on g-C3N4 towards efficient oxidation of alcohols under mild conditions

Herein, a well-defined nanostructure with leaf-like WO3 nanoflakes decorated on g-C3N4 was constructed via a facile impregnation and subsequent annealing method. The prepared WO3/g-C3N4 exhibited excellent catalytic activity for the selective oxidation of alcohols under mild conditions, and satisfactory yields to the corresponding carbonyl compounds were achieved without using non-green additives and organic solvents. It was found that the enhanced catalytic activity could be attributed to the enlarged specific surface area, the well-defined nanostructure, and the strong interactions between WO3 and g-C3N4. The distribution of WO3 nanoflakes on the g-C3N4 support increased the number of catalytically active sites for this reaction. XPS analysis suggested that a synergistic electron effect occurred because of the electron transfer from g-C3N4 to WO3. Moreover, the effects of reaction temperature, reaction time, oxidant amount and catalyst dosage on catalytic activity were investigated. Recycle studies showed that the catalyst could be readily recovered and no obvious decrease in catalytic efficiency was observed after seven cycles. The present catalytic system can afford a wide substrate scope for both aryl and alkyl alcohols with superior conversion and selectivity. Also, a plausible reaction mechanism was proposed to better illustrate the catalytic process. This work might provide a facile construction of a well-defined WO3/g-C3N4 catalyst for the selective oxidation of alcohols using a sustainable approach.