0D/2D Co0.85Se/TiO2 p–n heterojunction for enhanced photocatalytic H2 evolution

Photocatalytic H2 evolution is a promising way to obtain green H2 due to its clean and sustainable characteristics. Herein, a series of 0D/2D Co0.85Se/TiO2 heterojunctions were fabricated through a successive two-step hydrothermal strategy. Among them, 15%-Co0.85Se/TiO2 displays the most excellent H2 rate of 2312.5 μmol g−1 h−1, which is 10.3 times and 10.8 times higher than that of TiO2 and Co0.85Se, respectively. And the H2 production rate per electrochemically active surface area of 15%-Co0.85Se/TiO2 is 127.41, which is obviously more than that of TiO2 (14.17) and Co0.85Se (5.39). Based on the core-level alignment method and free radical capture tests, the enhanced activity mainly resulted from the higher electrochemically active surface area and the formation of a p–n heterostructure between TiO2 and Co0.85Se. This research provides a strategy for the development of noble metal-free nanocomposites for efficient photocatalytic H2 production.