Cobalt Titanate–Phosphorous-Doped g-C₃N₄ Heterostructure with Impressive Electrocatalytic Activity for Oxygen Evolution Reaction

Hydrogen (H₂) is a viable alternative to the finite fossil fuels to meet the escalating energy demands. Water splitting is a cleaner way of producing H₂, which can effectively generate electricity via fuel cells. The slower oxygen evolution reaction (OER) with large overpotential hinders the practicality of the electrocatalytic water-splitting process to generate H₂. Cobalt titanate (CoTiO₃) and graphitic carbon nitride (g-C₃N₄) are promising candidates for OER catalysts. The composite of CoTiO₃ supported on phosphorous doped g-C₃N₄ substrate (CoTiO₃/P-C₃N₄) has been synthesized and demonstrated as an excellent electrocatalyst with enhanced charge transport properties exhibiting a lower overpotential of 310.0 mV, a lower charge transfer resistance (R_ct) and faster OER kinetics. The synergistic interaction of CoTiO₃ and P-C₃N₄ at the hetero-interface has resulted in enhancing the conductivity and the accessible active sites. The composite also exhibited appreciable operational stability and Faradaic efficiency. CoTiO₃/P-C₃N₄ was thus proved to be competent to substitute the unstable and expensive benchmark catalysts in terms of cost, activity, and stability.