K/Cl Dual-Mediated Spatial Charge Separation in Carbon Nitride Boosts Piezocatalytic Pure Water Splitting

Graphite-phase carbon nitride is regarded as a highly promising piezoelectric catalyst, yet its interlayer and in-plane charge transfer capabilities pose significant limitations to its application. In this study, Cl, K co-modulated carbon nitride was synthesized via the molten salt method. The in-plane introduction of Cl, which exhibits an electron-withdrawing effect, breaks the symmetry of the carbon nitride crystals and enhances the structural polarity. Meanwhile, the interlayer intercalation of K reduces the localized states of electrons, and expands the π-conjugated system, serving as a new carriers' channel facilitating the interlayer transfer of carriers. The piezocatalytic hydrogen production rate from pure water of the optimized CNM-7.5 is 13.9 times that of the unmodified pristine CN. This work offers valuable foundation for application of piezocatalytic water splitting for hydrogen production, contributing to the advancement of hydrogen energy technology and the realization of a clean and sustainable energy system.