Synthesis, characterization and photocatalytic properties of WO3/hexagonal platelet graphite nanocomposites

Abstract

The WO3/hexagonal platelet graphite (HPG) composite was successfully prepared by impregnation of ammonium paratungstate (1, 3, 5 and 7 W% W) and hexagonal platelet graphite and subsequent calcination at 500 °C. The synthesized samples were characterized by using powder XRD, FTIR, SEM, DR UV–vis, XPS and N2-physisorption techniques. The characterization results showed that WO3 were well dispersed upon the HPG surface to form nanocomposite structure dependent upon W loading (optimum 5 W%). As compared to bare HPG and WO3, the synthesized W/HPG nanocomposites exhibited significantly enhanced photocatalytic degradation of p-nitrophenol under visible irradiation, providing prevailing evidence for the conjugation of WO3 with HPG. The influence of the reaction time, the catalyst amount, and pH of the solution was studied. The degradation efficiency was reached up to 98% under acidic pH, a catalyst amount of 0.01 g, in a reaction time of 100 min. The evaluation of photocatalytic performance of synthesized nanocomposites for the degradation of p-nitrophenol under visible light irradiation follow the trend: 5W/HPG > 3W/HPG > 7W/HPG > 1W/HPG. After five recycles, the photocatalytic activity of composites did not decline and demonstrated good performance for synthesized composites. The perceived improvement in photocatalytic degradation efficiency of the WO3-HPG nanocomposites could be attributed to the synergy of the well narrowed band gap, high surface area and effectual control of e−-h+ recombination.