Dislocation-engineered piezocatalytic water splitting in single-crystal BaTiO₃

The rapid development of society has exacerbated energy scarcity, making water splitting a promising solution for humanity to produce green hydrogen. Therefore, enhancing the relatively low catalytic performance of piezoelectric bulk catalysts is crucial to unlocking their potential for broader practical applications and potentially alleviating contemporary energy demands. Here, we introduce a sustainable doping strategy that deliberately imprints dislocations and their associated strain fields without additional elements into barium titanate single crystals to address the challenges faced by bulk piezoelectric catalysts. The presence of highly-oriented {100}〈100〉dislocations in plastically deformed materials was observed utilizing bright-field transmission electron microscopy. The strains induced by dislocations were mapped using high-angle annular dark-field and geometric phase analysis techniques. According to experimental observations and density functional theory calculations, the deformed materials exhibit superior performance in terms of electrical conductivity, ultrasonic response, and hydrogen adsorption-free energy. As result a nearly fivefold increase in piezoelectric catalytic performance, as compared to undeformed reference materials, is achieved. Our work demonstrates the potential of dislocation engineering to boost bulk piezoelectric catalysts, thereby challenging the current reliance on powder-based catalysts.