title: Template-free synthesis of core-shell TiO2 microspheres covered with high-energy {116}-facet-exposed N-doped nanosheets and enhanced photocatalytic activity under visible light.
abstract: Core-shell TiO2 microspheres possess a unique structure and interesting properties, and therefore, they have received much attention. The high-energy facets of TiO2 also are being widely studied for the high photocatalytic activities they are associated with. However, the synthesis of the core-shell structure is difficult to achieve and requires multiple-steps and/or is expensive. Hydrofluoric acid (HF), which is highly corrosive, is usually used in the controlling high-energy facet production. Therefore, it is still a significant challenge to develop low-temperature, template-free, shape-controlled, and relative green self-assembly routes for the formation of core-shell-structured TiO2 microspheres with high-energy facets. Here, we report a template- and hydrofluoric acid free solvothermal self-assembly approach to synthesize core-shell TiO2 microspheres covered with high-energy {116}-facet-exposed nanosheets, an approach in which 1,4-butanediamine plays a key role in the formation of nanosheets with exposed {116} facets and the doping of nitrogen in situ. In the structure, nanoparticle aggregates and nanosheets with {116} high-energy facets exposed act as core and shell, respectively. The photocatalytic activity for degradation of 2,4,6-tribromophenol and Rhodamine B under visible irradiation and UV/Vis irradiation has been examined, and improved photocatalytic activity under visible light owing to the hierarchical core-shell structure, {116}-plane-oriented nanosheets, in situ N doping, and large surface areas has been found.
authors.affiliation: Advanced Building Materials Engineering Research Centre, The Ministry of Education, Shandong Provincial Key Laboratory of Preparation and Measurement of Building Materials, University of Jinan, Nanxinzhuang West Rd 336, Jinan, Shandong 250022 (P.R. China). qfchen@126.com.
authors.forename: Qifeng
authors.initials: Q
authors.lastname: Chen
authors.forename: Baosheng
authors.initials: B
authors.lastname: Ren
authors.forename: Yubao
authors.initials: Y
authors.lastname: Zhao
authors.forename: Xun
authors.initials: X
authors.lastname: Xu
authors.forename: Heyi
authors.initials: H
authors.lastname: Ge
authors.forename: Ruifang
authors.initials: R
authors.lastname: Guan
authors.forename: Jincai
authors.initials: J
authors.lastname: Zhao
keywords: core-shell structures; high-energy facets; photocatalysis; self-assembly; titanium dioxide