External fields enhanced photocatalysis.

Efficient conversion of solar energy by means of photocatalysis shows huge potential to relieve energy crisis and environmental pollution. However, the unsatisfied conversion efficiency still hinders its practical application. Introduction of external fields can remarkably enhance the photocatalytic performance of semiconductors from the inside out. This review focuses on the recent advances in the diversified external fields, involving the microwave, mechanical stress, temperature gradient, electric field, magnetic field and coupled fields, boosted photocatalytic reactions, including contaminant degradation, water splitting, CO 2 reduction and bacterial inactivation. The relevant reinforcement mechanisms of photoabsorption, transport and separation of photoinduced charges and adsorption of reactions by the external fields are highlighted. Finally, the challenges and future outlook for the development of external field enhanced photocatalysis are presented.