Piezopotential augmented photo- and photoelectro-catalysis with a built-in electric field

Rapid technological development and population growth are responsible for a series of imminent environmental problems and an ineluctable energy crisis. The application of semiconductor nanomaterials in photocatalysis or photoelectrocatalysis (PEC) for either the degradation of contaminants in the environment or the generation of hydrogen as clean fuel is an effective approach to alleviate these problems. However, the efficiency of such processes remains suboptimal for real applications. Reasonable construction of a built-in electric field is considered to efficiently enhance carrier separation and reduce carrier recombination to improve catalytic performance. In the past decade, as a new method to enhance the built-in electric field, the piezoelectric effect from piezoelectric materials has been extensively studied. In this review, we provide an overview of the properties of piezoelectric materials and the mechanisms of piezoelectricity and ferroelectricity for a built-in electric field. Then, piezoelectric and ferroelectric polarization regulated built-in electric fields that mediate catalysis are discussed. Furthermore, the applications of piezoelectric semiconductor materials are also highlighted, including degradation of pollutants, bacteria disinfection, water splitting for H₂ generation, and organic synthesis. We conclude by discussing the challenges in the field and the exciting opportunities to further improve piezo-catalytic efficiency.