Exploration of the electrocatalytic activity of nonlinear optically active CuWO4/g-C3N4 nanocomposites

Abstract

This research focused on successfully synthesizing CuWO₄/g-C₃N₄ nanocomposites using microwave assistance, and their potential as electrochemical supercapacitors and electrocatalysts for the hydrogen and oxygen evolution reactions was thoroughly investigated. Structural studies demonstrated the anchoring of the spherical CuWO₄ nanoparticles with a triclinic structure on the g-C₃N₄ surface. The CuWO₄/g-C₃N₄ system showed an impressive specific capacitance of 111 F g⁻¹ and excellent stability (85%) in supercapacitor applications. It also exhibited remarkable bifunctional electrocatalytic performance, efficiently facilitating both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in distinct electrolytes. Notably, it achieved a standard current density of 10 mA cm⁻² with significantly lower Tafel slopes (46 mV dec⁻¹ (HER) and 104 mV dec⁻¹ (OER)) compared to pristine CuWO₄. The nanocomposite's superior electrochemical performance was attributed to the synergistic effect of g-C₃N₄ and CuWO₄, leading to high capacitance and excellent catalytic activity. Additionally, the nanocomposite exhibited enhanced nonlinear absorption and refraction upon He–Ne laser excitation, suggesting potential applications in optical devices. These findings highlight the promising prospects of CuWO₄/g-C₃N₄ nanocomposites as multifunctional materials for energy storage and catalysis. DFT calculations further validate the experimental findings by providing insights into the electronic structures, quantum capacitance, adsorption geometries, and overpotentials of the hybrid systems. The calculated overpotential trend of CuW/gCN < CuW agrees with the experimental data.