Abstract:

Rationally engineering the microstructure and electronic structure of catalysts to induce high activity for versatile applications remains a challenge. Herein, chlorine doped graphitic carbon nitride (Cl-doped g-C₃N₄) nanorings have been designed as a superior photocatalyst for pollutant degradation and oxygen evolution reaction (OER). Remarkably, Cl-doped g-C₃N₄ nanorings display enhanced OER performance with a small overpotential of approximately 290 mV at current density of 10 mA cm^-2 and Tafel slope of 83 mV dec^-1, possessing comparable OER activity to precious metal oxides RuO₂ and IrO₂/C. The excellent catalytic performance of Cl-doped g-C₃N₄ nanorings originates from the strong oxidation capability, abundant active sites exposed and efficient charge transfer. More importantly, visible light irradiation gives rise to a prominent improvement of the OER performance, reducing the OER overpotential and Tafel slope by 140 mV and 28 mV dec^-1, respectively, demonstrating the striking photo-responsive OER activity of Cl-doped g-C₃N₄ nanorings. The great photo-induced improvement in OER activity would be related to the efficient charge transfer and the ?OH radicals arising spontaneously on CN-Cl₁₀₀ catalyst upon light irradiation. This work establishes Cl-doped g-C₃N₄ nanorings as a highly competitive metal-free candidate for photoelectrochemical energy conversion and environmental cleaning application.

Key words: Cl-doped g-C₃N₄, Nanoring, Electrocatalysts, Oxygen evolution reaction, Pollutant degradation