Cocatalyst engineering to weaken the charge screening effect over Au–Bi4Ti3O12 for piezocatalytic pure water splitting

The weak driving force and rapid carrier recombination severely restrict the development and utilization of piezocatalysis, but the important reason is the charge screening effect. Herein, a dual electric field driven piezoelectric catalytic system was constructed according to deposition of Au nanoparticles on the different crystal planes of BTO. Owing to the unmatched work function between Au and BTO, a Schottky junction at the interface could be formed, resulting in a depletion region at the BTO surface with a reduced charge density. Thus, a built-in electric field from the surface of BTO to the inside is established due to the unbalanced charge distribution. In the process of piezocatalysis, the built-in electric field could assist the piezoelectric field to separate carriers, which increases the carrier migration path, weakens the shielding effect and reduces the recombination of carrier. Meanwhile, Au could also supply the active site for the electron reduction reaction. Under the cooperation of the piezoelectric field of BTO and Au nanoparticles, Au–BTO achieved an elevated H2 production rate of 194.67 μmol h−1 g−1, accompanied by high-added H2O2 production. This work provides a new route for designing efficient piezocatalysts.