Boosting the catalytic performance of carbon nitrides for overall water splitting by tuning the C/N ratio: A theoretical investigation

We systematically study the catalytic activity of carbon nitride materials by controlling the carbon-to-nitrogen ratio and engineering their morphological structure. The electrocatalytic activities of five types of carbon nitrides with different C/N ratios— C₄N, C₃N, C₂N, CN, and C₃N₄ — toward the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are theoretically evaluated. The results show that the OER overpotential decreases as the nitrogen content increases, reaching its lowest value in CN. Our results highlight CN as a bifunctional electrocatalyst with acceptable performance with overpotentials of 0.76 and 0.05 V for OER and HER, respectively.