中科院等离子体物理研究所知识库

Identification of the role of the specific surface area and surface structure as a key factor for photocatalytic performance remains a controversial topic. In this work, three types of N-doped anatase TiO2 with different morphologies are newly synthesized by changing the addition order for the reagents. Methyl orange, Rhodamine B and Congo red are selected to showcase the photoactivity of the synthesized Ndoped TiO2. The photocatalytic experimental results show that Congo red can be selectively and rapidly degraded by three different N-doped TiO2 samples. Interestingly, although a microspiny sphere structure possesses a larger specific surface area compared to a microflower structure, a microflower structure dominated by {1 0 0) and {1 0 1) facets exhibits a higher photocatalytic efficiency compared to a microspiny structure dominated by {1 0 1) facets, as demonstrated by a quicker photodegradation rate for Congo red, higher photocurrent density, smaller semicircle in the electrochemical impedance spectrum, and lower photoluminescence intensity. Thus, the result suggests that the surface structure plays a more important role compared to the surface area. In addition, a hollow microsphere structure with the largest specific surface area exhibits the best performance in terms of photodegradation, charge separation ability and electron-hole recombination efficiency, indicating that the proper surface morphology combined with a large specific surface area is greatly promising for enhancement of photoactivity. (C) 2018 Elsevier Inc. All rights reserved.