title: Effects of adsorbed F, OH, and Cl ions on formaldehyde adsorption performance and mechanism of anatase TiO2 nanosheets with exposed {001} facets.
abstract: Formaldehyde (HCHO), as the main indoor air pollutant, is highly needed to be removed by adsorption or catalytic oxidation from the indoor air. Herein, the F(-), OH(-), and Cl(-)-modified anatase TiO2 nanosheets (TNS) with exposed {001} facets were prepared by a simple hydrothermal and post-treatment method, and their HCHO adsorption performance and mechanism were investigated by the experimental analysis and theoretical simulations. Our results indicated that the adsorbed F(-), OH(-), and Cl(-) ions all could weaken the interaction between the HCHO and TNS surface, leading to the serious reduction of HCHO adsorption performance of TNS. However, different from F(-) and Cl(-) ions, OH(-) ion could induce the dissociative adsorption of HCHO by capturing one H atom from HCHO, resulting in the formation of one formyl group and one H2O-like group. This greatly reduced the total energy of the HCHO adsorption system. Thus, the adsorbed OH(-) ions could provide the additional active centers for HCHO adsorption. As a result, the NaOH-treated TNS showed the best HCHO adsorption performance mainly because its surface F(-) was replaced by OH(-). This study will provide new insight into the design and fabrication of high performance adsorbents for removing indoor HCHO and, also, will enhance the understanding of the HCHO adsorption mechanism.
authors.affiliation: State Key Laboratory of Advanced Technology for Material Synthesis and Processing, Wuhan University of Technology, Luoshi Road 122#, Wuhan 430070, PR China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhou
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zhu
authors.forename: Jiaguo
authors.initials: J
authors.lastname: Yu
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
mesh_terms: D000327:Adsorption; D002384:Catalysis; D005461:Fluorine / Q000737:chemistry*; D005557:Formaldehyde / Q000737:chemistry*; D006878:Hydroxides / Q000737:chemistry*; D007477:Ions; D053758:Nanoparticles / Q000737:chemistry; D010084:Oxidation-Reduction; D014025:Titanium / Q000737:chemistry
chemical_list: D006878:Hydroxides; D007477:Ions; C009495:titanium dioxide; D005557:Formaldehyde; D005461:Fluorine; C031356:hydroxide ion; D014025:Titanium