Heterogeneous Interface Design to Enhance the Photocatalytic Performance.

Abstract

Heterojunction photocatalysts, which can relieve the low carrier separation efficiency and insufficient light absorption ability of one catalyst, have received extensive attention. To construct an ideal heterojunction for photocatalysis, most previous studies focused on energy band structure engineering to prolong charge carrier lifetime and increase the reaction rates, which are critical to increase the photocatalytic activity. Here, the heterojunction interface was surprisingly found to be another important factor to affect the photocatalytic performance. We design three heterojunction interface models of α-Fe2O3/Bi2O3, corresponding to "ring-to-face", "face-to-face", and "rod-to-face". By tuning the heterogeneous interfaces, the photocatalytic performance of composites was significantly improved. On the basis of the type I energy band structures, the optimized face-to-face model realized a photocatalytic efficiency of 90.8% that of pure α-Fe2O3 (<30%) for degradation of methylene blue and a higher efficiency (80%) for degrading tetracycline within 60 min, which were superior to most Fe/Bi/O-based photocatalytic heterojunctions. Furthermore, the results disclosed that the enhanced performance was owing to the sufficient interfacial contact and low interfacial resistance of the face-to-face model, which provided sufficient channels for efficient charge transfer. This work offers a new direction of tuning heterojunction interface for designing composite photocatalysts.