Endogenous bromine species synergistic stabilization strategy for enhancing the stability of CsPbBr3 and accelerating the degradation of decabromodiphenyl ether under visible light

The formation of Br vacancies is the core factor leading to significant impairment of CsPbBr 3 ′s stability. Herein, we ingeniously designed an endogenous bromine species synergistic stabilization strategy by constructing a CsPbBr 3 /Cs 4 PbBr 6 heterojunction photocatalyst and decabromodiphenyl ether (BDE209) degradation. Via precise control of the Cs 2 CO 3 /PbBr 2 stoichiometric ratio, the optimal sample (CPB-0.8) exhibited exceptional BDE209 debromination activity with a rate constant of 0.275 min −1 and nearly complete degradation within 10 min under visible light (λ > 400 nm). More importantly, it shows significantly enhanced stability compared to pure single-phase CsPbBr 3 . Structural characterizations confirmed that Cs 4 PbBr 6 in the heterojunction acts as a stabilizing phase. It dissolves in situ to release CsBr, which dynamically passivates Br vacancies on CsPbBr 3 surfaces, preventing CsPbBr 3 from transforming to inactive Cs 2 PbBr 5 . Meanwhile, bromine species released during BDE209 degradation further assist in suppressing the formation of Br vacancies and halide ion loss in CsPbBr 3 . This work demonstrates the potential synergistic effect between the efficient degradation of halogenated pollutants and the stabilization of halogen vacancies of metal halide perovskites.