CaMoO4/CaWO4 heterojunction micro/nanocomposites with interface defects for enhanced photocatalytic activity

Abstract

The polyacrylamide gel method combined with low temperature calcination technology (PGMCLCT) have been applied to prepare the CaMoO4/CaWO4 heterojunction micro/nanocomposites with novel light emission and high photocatalytic activity for the degradation of methylene blue (MB) dye. A variety of characterization methods confirmed the formation of heterojunctions between CaMoO4 and CaWO4 in a special interface contact way. The CaMoO4/CaWO4 heterojunction micro/nanocomposites exhibits a novel emission peak at 400 nm with the excitation wavelength of 240 nm and high photocatalytic activity for the degradation of MB dye. With the increase of the mass percentage of CaWO4, the fluorescence emission intensity of CaMoO4/CaWO4 heterojunction micro/nano composites decreases, while the photocatalytic activity increases gradually. The effects of catalyst content, initial dye concentration and cycle index on the photocatalytic activity of CaMoO4/CaWO4 heterojunction micro/nanocomposites were systematically studied. The optimal catalyst content, initial dye concentration, irradiation time and cycle index are 1 g/L, 20 mg/L, 180 min and 5, respectively. The CaMoO4/ wt 20% CaWO4 heterojunction micro/nanocomposites exhibits highest degradation percentage of about 91.44% due to the carbon skeleton or adsorbed oxygen accelerates the separation of photogenerated electrons and hole pairs. This method provides a technical reference for the synthesis of other types of heterojunction micro/nanocomposites.