Amorphous/Crystalline Interface of Bi/Bi₄NbO₈Cl Heterostructure for Improved Piezo-Photocatalysis

Efficient separation of photogenerated charges at the surface of photocatalysts is vital for achieving high photocatalytic activity. Here, a Bi/Bi₄NbO₈Cl heterostructure piezo-photocatalyst with an amorphous/crystalline interface (acBi/BNC) is prepared by in situ reduction using Bi₄NbO₈Cl as a self-sacrificial template. This ingenious design synergistically utilizes the advantages of the amorphous/crystalline interface structure, localized surface plasmon resonance effect, and piezoelectric field. The formation of amorphous/crystalline interfaces induces the generation of oxygen vacancies, and subsequently lattice distortions, thus improving the piezoelectric properties. Theoretical and experimental results demonstrate that the combination of piezoelectric field and amorphous/crystalline interface promotes the effective separation and migration of photogenerated charges between the bulk and surface of the catalysts. Under simultaneous light and ultrasound, the optimal heterostructure (acBi/BNC-3) exhibit superior photodegradation efficiency of tetracycline reached 80% within 5 min, and the reaction rate (2.78 × 10^-1 min^-1) is 7.8 and 5.4 times that of pure Bi₄NbO₈Cl (BNC) and crystalline Bi/Bi₄NbO₈Cl (cBi/BNC), respectively. Furthermore, the piezo-photocatalytic tetracycline degradation efficiency surpasses those under individual photocatalysis and piezocatalysis conditions. This work provides a novel rational design to improve the spatial charge separation of Bi-based catalysts and prepare high-performance piezo-photocatalysts via interface engineering.