Bi@Bi2WO6 with oxygen vacancies: A strategy for enhancing piezo-response and bandgap reconstruction to improve 2,4-DCP degradation

This work successfully synthesized Bi@Bi 2 WO 6 with oxygen vacancies (OVs) through chemical etching and systematically revealed the coupling mechanism between OVs and piezoelectric effects. In the piezo-photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP), the 0.1al-BBW sample exhibited the best performance, with an apparent rate constant of 0.05468 min −1 . ERS and PFM characterizations revealed that abundant OVs were introduced by etching, leading to lattice modification and improved piezoelectric polarization. According to density functional theory (DFT) results, the piezoelectric field optimizes charge localization at OVs, strengthens band coupling, reduces carrier recombination, and facilitates the activation of H 2 O and O 2 . Furthermore, Mott-Schottky results and stress-induced simulations (0–8 %) confirmed that both piezoelectric polarization and OVs contribute synergistically to energy band restructuring. Pathway analysis showed that 1 O 2 and h + were the dominant reactive species driving the two main routes of 2,4-DCP decomposition. Overall, this work offers mechanistic insights into OVs coupling with piezoelectric and presents a viable strategy for designing advanced piezo-photocatalysts with multifunctional capabilities.