CuWO 4 /CNT/g‐C 3 N 4 Hybrid Electrode: A Bifunctional Material for High‐Performance Supercapacitor and Hydrogen Evolution

For various kinds of electrochemical energy storage and conversion devices, hybrid materials comprising of transition‐metal compounds and nitrogen (N) based carbonaceous compounds are considered as potential electrocatalysts. The synergistic interaction between metallic sites and N dopants is responsible for the enhanced activity of these electrocatalysts. The mechanism and interaction of bimetallic systems are less investigated compared with single‐metal catalysts. This study represents the development and fabrication of a hybrid electrode based on copper tungstate/carbon nanotubes (CuW/CNT) and copper tungstate/carbon nanotubes/graphitic carbon nitride (CuW/CNT/gCN) using hydrothermal method. X‐ray diffraction spectroscopy (XRD) verified that CuW/CNT/gCN has a triclinic crystal structure and SEM images showed that g‐C 3 N 4 nanosheets have CuWO 4 nanoparticles wrapped together with CNTs. Using XPS, the coexistence of the elements Cu, W, O, C, and N was investigated in relation to their energy states and binding energies. Electrochemical experiments revealed that the CuW/CNT/gCN electrode exhibited a higher specific capacitance of 233 F/g and 94% of cyclic stability compared with CuW/CNT, displaying better ion storage behavior. Remarkable HER performance was demonstrated by the CuW/CNT/gCN nanocomposite in alkaline medium. Furthermore, compared to CuW/CNT, it achieved a standard current density of 10 mA cm −2 with substantially smaller overpotentials. The higher electrocatalytic capabilities of CuW/CNT/gCN composite attribute to the efficient heterojunction that forms between porous matrix of g‐C 3 N 4 and the CuWO 4 matrix, where the CNT functions as a conducting bridge promoting the ion diffusion paths for enhanced conductivity.