Schottky-driven interfacial design of Bi₂MoO₆/Ti₃C₂T_x heterostructure for boosted piezocatalytic hydrogen evolution

Abstract

Piezoelectric semiconductor catalysis is gaining attention as a strategy to convert mechanical energy into chemical energy for sustainable hydrogen production. Similar to photocatalysis, piezocatalysis involves the generation, separation, migration, and surface reaction of piezo-induced charge carriers. Here, we report the rational design of Bi₂MoO₆/Ti₃C₂T_x piezocatalysts synthesized via electrostatic self-assembly and evaluate their hydrogen evolution performance. The optimized heterostructure achieves a hydrogen evolution rate of 1.99 ${mmol}{g}^{-1}{h}^{-1}$, which is 2.75 and 5.78 times higher than pristine Bi₂MoO₆ and nanolayered Ti₃C₂T_x, respectively. Experimental characterization combined with density functional theory calculations demonstrates that the heterointerface facilitates rapid electron transfer and enhances the intrinsic piezoelectric response. Furthermore, the interface reduces the hydrogen adsorption energy barrier and improves Gibbs free energy for water splitting, leading to enhanced charge separation and suppressed carrier recombination. A Schottky junction-based mechanism is proposed to explain directional charge transport and surface redox reactions under mechanical stimulation, providing new design insights for high-efficiency piezocatalysts driven by low-intensity mechanical energy.