The synergistic effect and mechanism of proton-functionalized C3N5/MoS2 heterojunctions in piezo-photocatalytic bifunctional materials

Semiconductor photocatalysis faces critical challenges, including limited visible-light absorption and rapid charge recombination. Overcoming these bottlenecks is essential for its environmental and energy applications. In this work, a MoS 2 /HCN S–scheme heterojunction was constructed by integrating protonated C 3 N 5 with MoS 2 nanosheets. This architecture was specifically engineered to establish a synergistic piezo-photocatalytic effect by leveraging the intrinsic asymmetry of the N-rich C 3 N 5 framework. Under simultaneous solar and ultrasonic irradiation, the MoS 2 /HCN heterojunction achieved a remarkable 99% degradation of tetracycline hydrochloride within only 15 min. The degradation rate constant reached 0.249 min −1 , representing a 22.6-fold enhancement compared to the 0.011 min⁻ 1 observed for pristine C 3 N 5 . Furthermore, the composite delivered a superior hydrogen evolution rate of 14.83 mmol g -1 h −1 . Mechanistic analysis, supported by in-situ characterizations, confirms that the internal piezoelectric field effectively drives directional carrier separation and significantly boosts surface redox kinetics. This study demonstrates a promising strategy for harnessing multiple environmental energy sources through advanced interface engineering, providing a practical blueprint for integrated pollution remediation and green energy conversion.