Enhancing piezocatalytic H2O2 production through morphology control of graphitic carbon nitride

Piezocatalytic H2O2 production has attracted significant attention as a green alternative to traditional anthraquinone methods with heavy environmental pollution and high energy consumption. However, since the efficiency of piezocatalyst in producing H2O2 is poor, searching for a suitable method to improve the yield of H2O2 is of great interest. Herein, a series of graphitic carbon nitride (g-C3N4) with different morphologies (hollow nanotube, nanosheet and hollow nanosphere) are applied to enhance the piezocatalytic performance in yielding H2O2. The hollow nanotube g-C3N4 exhibited an outstanding H2O2 generation rate of 262 umol·g-1·h-1 without any co-catalyst, which is 1.5 and 6.2 times higher than nanosheets and hollow nanospheres, respectively. Piezoelectric response force microscopy, piezoelectrochemical tests, and Finite Element Simulation results revealed that the excellent piezocatalytic property of hollow nanotube g-C3N4 is mainly attributed to its larger piezoelectric coefficient, higher intrinsic carrier density, and stronger external stress absorption conversion. Furthermore, mechanism analysis indicated that piezocatalytic H2O2 production follows a two-step single-electro pathway, and the discovery of 1O2 furnishes a new insight into explore this mechanism. This study offers a new strategy for the eco-friendly manufacturing of H2O2 and a valuable guide for future research on morphological modulation in piezocatalysis.