Unprecedented electrochemical activity of GdCoO₃-gC₃N₄ nanocomposite for bifunctional oxygen and hydrogen evolution reaction

Development of highly competent and stable electrocatalysts for electrochemical water splitting to attain oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is highly desired. Here in present work, gadolinium cobalt oxide (GdCoO₃), graphitized carbon nitride (gC₃N₄), and their composite is fabricated via hydrothermal method, and then used as electrocatalysts for OER and HER. The prepared electrocatalysts underwent rigorous characterization using X-ray diffraction (XRD) to unravel their structural composition. To further unravel their morphological and textural aspects, scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) techniques were employed. Intriguingly, the synergy of nanoparticles GdCoO₃ anchored onto thin nanosheets of gC₃N₄ exhibited a remarkable surge in OER and HER activities in a 1.0 M KOH electrolyte solution. The composite material showed a remarkable reduction in onset potential of 0.95 V vs Ag/AgCl for OER. On the other hand, impressively it shows the low overpotentials of 210 mV at 10 mA cm⁻² with a tafel slope of 44 mV dec⁻¹. Notably, for HER the nanocomposite requires an onset potential of 0.01 V vs Ag/AgCl and 230 mV overpotential to achieve a current density of 10 mA cm⁻². The enhanced results are due to that the GdCoO₃ nanoparticles integrated onto the nanosheets of gC₃N₄ shows high surface area and synergistic effect exhibited, which displayed good stability, and are useful for commercial applications. Thus, the exceptional OER performance of the composite combined with its good electrochemical properties, positions it as a viable option for large-scale and sustainable water splitting technologies.