Review on heterophase/homophase junctions for efficient photocatalysis: The case of phase transition construction

Semiconductor photocatalysts are extensively applied in environmental treatment and energy conversion. However, one of their major disadvantages is their relatively low photocatalytic performance owing to the recombination of generated electron-hole pairs. The presence of the phase junction is an effective way to promote the photocatalytic activity by increasing the separation efficiency of the electron-hole pairs. Accordingly, extensive research has been conducted on the design of phase junctions of photocatalysts to improve their charge transfer properties and efficiencies. Therefore, for the design of an appropriate phase junction and the understanding of the mechanism of electron-hole separation, the development of the photocatalytic phase junction, including the preparation methods of the heterogeneous materials, is tremendously important and helpful. Herein, the commonly used, externally induced phase transformation fabrication techniques and the primary components of the semiconductors are reviewed. Future directions will still focus on the design and optimization of the phase junction of photocatalytic materials according to the phase transition with higher efficiencies for broadband responses and solar energy utilization. Additionally, the most popular phase transformation fabrication techniques of phase junctions are briefly reviewed from the application viewpoint.