Piezoceramics Boosting Photocatalytic Hydrogen Evolution of Covalent Organic Frameworks

Precise manipulation of charge-carrier transport dynamics is a pivotal yet challenging attribute in enhancing the efficiency of energy-conversion systems. Herein, piezopotential and optimized energy band alignment are leveraged to construct a core-shell Z-scheme heterostructure, covalently bonding BaTiO₃ nanowires (a piezoelectric ceramic) with TpPa (an imine-linked covalent organic framework). This synergistic combination effectively overcomes the intrinsic limitations of the individual components, particularly in driving photocatalytic water splitting. The resultant Z-scheme heterostructure exhibits a broadened visible-light absorption range, finely tuned energy band alignment, abundant exposure of active sites, and enhanced piezo-driven charge separation, collectively leading to remarkable improvements in charge-carrier transfer and utilization efficiency. As a result, an impressive H₂ evolution rate of 33 mmol g^-1 h^-1 and an outstanding apparent quantum yield of 9.39% are achieved, representing enhancements of 4.56-fold and 10.06-fold, respectively, compared to pure photocatalysis. This work presents an effective strategy for designing high-efficiency catalysts and highlights the potential of piezoelectricity in boosting photo-redox reactions.