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

The polyacrylamide gel method combined with low temperature calcination technology (PGMCLCT) have been applied to prepare the CaMoO 4 /CaWO 4 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 CaMoO 4 and CaWO 4 in a special interface contact way. The CaMoO 4 /CaWO 4 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 CaWO 4 , the fluorescence emission intensity of CaMoO 4 /CaWO 4 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 CaMoO 4 /CaWO 4 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 CaMoO 4 / wt 20% CaWO 4 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. The CaMoO 4 /CaWO 4 heterojunction micro/nanocomposites with novel light emission and high photocatalytic activity for the degradation of MB dye were successfully synthesized by the polyacrylamide gel method combined with low temperature calcination technology. The CaMoO 4 /CaWO 4 heterojunction micro/nanocomposites exhibits a novel emission peak at 400 nm with the excitation wavelength of 240 nm. With the increase of CaWO 4 content, the emission peak intensity of CaMoO 4 /CaWO 4 heterojunction micro/nanocomposites decreases and the photocatalytic activity increases. Carbon skeleton or adsorbed oxygen plays the role of electron transport in the whole photocatalytic process, which accelerates the separation of photogenerated electrons and hole pairs in the CaMoO 4 /CaWO 4 heterojunction micro/nanocomposites, thus enhancing the photocatalytic activity of the system.