Abstract It remains a great challenge to overcome the problems of poor conductivity and rapid charge recombination in bismuth oxybromide (BiOBr). Herein, for the first time we report the synergistic effect of oxygen vacancies (Ov) and p-n heterojunction to improve photoelectrochemical performance of BiOBr. Benefitting from the new electron donor level caused by oxygen vacancies, the visible-light absorption region, carrier concentration and exposure of {001} facets of BiOBr are all increased. In the meantime, the 2D p-n heterojunction between BiOBr and BiOI leads to a built-in electric field and thus significantly accelerating the charge separation and transfer. Upon visible light irradiation, the resulted BiOBr-Ov/BiOI photoanode presents robust photoelectrochemical performance, achieving a photocurrent density of 1.33 mA/cm2 at 1.23 V vs. RHE. This work not only provides new insight for designing efficient photoelectrodes but also highlights the importance of oxygen defect-engineering strategy in photoelectrochemical water splitting.

中文翻译：

---

氧空位和 pn 异质结修饰的 BiOBr 在可见光照射下提高供体密度和分离效率

摘要 如何克服溴氧化铋（BiOBr）导电性差和电荷复合快的问题仍然是一个巨大的挑战。在此，我们首次报道了氧空位（Ov）和 pn 异质结的协同效应，以提高 BiOBr 的光电化学性能。受益于氧空位引起的新电子供体能级，BiOBr 的可见光吸收区、载流子浓度和{001}面的暴露都增加了。同时，BiOBr 和 BiOI 之间的 2D pn 异质结导致内置电场，从而显着加速电荷分离和转移。在可见光照射下，所得的 BiOBr-Ov/BiOI 光阳极表现出强大的光电化学性能，在 1.23 V vs. RHE 下实现了 1.33 mA/cm2 的光电流密度。