Rutile-Coated B-Phase TiO₂ Heterojunction Nanobelts for Photocatalytic H₂ Evolution

In the field of photocatalysis, the crystal phase engineering of titanium dioxide is a research hotspot. Titanium dioxide heterojunctions often exhibit better photocatalytic performance than single-phase TiO2. Here, a two-step hydrothermal and calcination method is used to build the phase interface between TiO2 (B) and rutile for the first time, and a narrow band gap heterojunction TiO2 material is synthesized. The heterojunction TiO2 material is characterized by transmission electron microscopy (TEM), ultraviolet (UV), X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR). The two phases are connected by a corner-sharing at the phase interface. The different positions of the conduction bands and valence bands between the two phases result in the effective separation of photogenerated electrons and holes through the phase interface. Under light, the photogenerated holes are transferred to the rutile phase and quickly consumed by the sacrificial agent, and the surplus photogenerated electrons participate in the H2 evolution reaction. When the ratio of TiO2 (B) to rutile is about 2/1, the TiO2 (B)/rutile heterojunction exhibits the highest photocurrent and the best H2 evolution performance under the present experimental conditions.