科研之友
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摘要
Efficient photocatalysis for degrading environmental organic pollutants on semiconductors requires photogenerated charge carrier separation to drive the photochemical processes. To ensure charge separation, it is indispensable to make charges captured effectively. Generally, the step for capturing the photogenerated electrons by the surface adsorbed O-2 is relatively slow as compared to that for capturing holes by the surface adsorbed hydroxyl groups so that it is taken as the rate-determining step. However, it is frequently neglected. Thus, it is greatly desired to develop feasible strategies to promote the adsorption of O-2 for efficient photocatalysts. In this paper, we have mainly discussed surface modification with inorganic acids, such as H3PO4, HF, and H3BO3, to enhance photogenerated charge carrier separation based on oxygen adsorption promotion for photocatalytic degradation of environmental pollutants. Among these acids, the function and mechanism of H3PO4 are highlighted because of its good performance and universality. Several important photocatalyst systems, mainly including TiO2, alpha-Fe2O3, and g-C3N4, along with the nanostructured carbons as electron acceptors in nanocomposites, are addressed to improve the ability to adsorb O-2. A key consideration in this review is the development of a strategy for the promotion of adsorbed O-2 for efficient photocatalysts, along with the process mechanisms by revealing the relationships among the adsorbed O-2, photogenerated charge carrier separation, and photocatalytic performance. Interestingly, it is suggested that the enrichment in surface acidity be favorable for promotion of O-2 adsorption, leading to the improved charge carrier separation and then to the enhanced photoactivities of various semiconductor photocatalysts. Moreover, several outlooks are put forward.
- 出版日期2015-10-21
- 单位黑龙江大学
