Faradically dominant pseudocapacitive graphitic carbon nitride nanosheets decorated with strontium tungstate nanospheres for supercapattery device and hydrogen evaluation reaction

Abstract

Transition metal oxides are promising for hydrogen evolution reaction (HER) and hybrid energy storage due to their excellent redox properties, inherent electrochemical activity, and abundant electroactive sites. A significant challenge limiting their broader application is their intrinsic low electrical conductivity and reduced electrochemical stability. For hybrid energy storage devices and HER, a highly electrochemical active material is designed from 2D graphitic carbon nitride nanosheet (g-C₃N₄) networks anchored with strontium tungstate nanospheres (SrWO₄/g-C₃N₄). The excellent performance observed can be attributed to several factors: multiple electro-active sites, well-defined electronic structures, and interaction between SrWO₄ nanosphere on the surface of g-C₃N₄ nanosheets surface. The supercapattery device exhibited superior energy density (65.4 W h/kg) and power density (1240.5 W/kg) in comparison. In addition, the theoretical technique was utilized to provide a detailed analysis of the experimental findings. In addition, the SrWO₄/g-C₃N₄ material demonstrates a low overpotential of 129 mV at -10 mA/cm², along with Tafel slope values of 67 mV/dec for the HER, and it exhibits excellent cyclic stability. This study presents an advanced method for designing SrWO₄/g-C₃N₄-based supercapacitors and HER platforms with nanoscale structures and optimized interface arrangements.