Facile Synthesis of Cobalt Tungstate with Special Defect Structure with Enhanced Optical, Photoluminescence, and Supercapacitive Performances

The present study reports the gamma-ray irradiation assisted polyacrylamide gel synthesis and optical, photoluminescence and supercapacitive performances of cobalt tungstates with special defect structure. The analysis of X-ray powder diffraction data showed that the purity and crystallinity of CoWO4 increased with the increasing of sintering temperature. X-ray photoelectron spectroscopy and energy spectrum analysis show that the high purity CoWO4 powders does not contain any other impurities. Color and optical properties analysis indicates that the high purity CoWO4 powders exhibits a strongest blue color than that of other samples. The photoluminescence spectrum shows three obvious emission bands in ultraviolet (340-375 nm), blue (424-490 nm), and green light emission (510 nm) regions under 220 nm xenon lamp excitation, which are ascribed to the organic impurities, the transition of T-3(1u) levels to the (1)A(1g) level, and the partially allowed transition of T-1g to (1)A(1g), respectively. Studies on electrochemical properties demonstrate that the CoWO4 powder has an excellent prospect in the supercapacitors for advanced electrochemical energy storage applications.