Facile synthesis of 2D Bi4O5Br2/2D thin layer-Ti3C2 for improved visible-light photocatalytic hydrogen evolution

Photocatalytic hydrogen evolution via water splitting was considered as a promising way of solar energy conversion and storage in the past decades. However, the weak visible-light response and fast recombination of electron-hole pairs are still main obstacles to overcome. Herein, a novel 2D/2D Bi4O5Br2/TL-Ti3C2 (Thin layer-Ti3C2) visible-light photocatalyst was successfully prepared by in-situ synthesis of Bi4O5Br2 nanosheets on the surface of TL-Ti3C2 at room temperature. The resulting Bi4O5Br2/TL-Ti3C2 exhibits a higher hydrogen evolution activity (83.5 ​μmol·g−1·h−1) than that of pristine Bi4O5Br2 (44.9 ​μmol·g−1·h−1) under visible-light irradiation. The enhanced hydrogen evolution activity of as-prepared photocatalyst mainly attributes to the increased visible light responsiveness and rapid transfer of photo-induced electrons. The strong interaction between TL-Ti3C2 and Bi3+ in Bi4O5Br2 nanosheets establishes a good electron transfer channel and close contact, which accelerates the transfer of photo-induced electrons from Bi4O5Br2 to Ti3C2 and promotes the separation of photo-generated charge carriers, thereby increasing the number of effective photo-induced electrons involved in the hydrogen evolution. This work provides a new insight into the construction of BixOyBrz/MXene photocatalyst system, and demonstrated that Ti3C2 has excellent application potential in promoting the photocatalytic performance of bismuth-rich bismuth oxyhalides (BixOyXz X ​= ​Cl, Br, I). Benefiting from the rapidly transfers photo-induced electrons and increases the visible light responsiveness, the resulting 2D Bi4O5Br2/2D TL-Ti3C2 manifests more significant photocatalytic hydrogen evolution activity (83.5 ​μmol·g−1·h−1) than that of pristine Bi4O5Br2 (44.9 ​μmol·g−1·h−1). This work provides a new insight into the construction of BixOyBrz/MXene photocatalyst system, and demonstrated that Ti3C2 has excellent application potential in promoting the photocatalytic performance of bismuth-rich bismuth oxyhalides (BixOyXz X ​= ​Cl, Br, I). [Display omitted] •Bi4O5Br2/Thin layer-Ti3C2 was prepared by in-situ synthesis at room temperature.•Bi4O5Br2/Thin layer-Ti3C2 manifests better photocatalytic H2 evolution than Bi4O5Br2.•The enhanced activity was mainly attributed to the rapidly charge transfer.•An electron transfer channel was established in Bi4O5Br2/Thin layer-Ti3C2.•The possible H2 evolution mechanism of Bi4O5Br2/Thin layer-Ti3C2 was proposed.