Band structure and component content are the key factors for determining the activity of semiconductor heterojunction. In this study, a novel Bi_5O_7I/BiOBr_xI_(1-x)heterostructure was synthesized by a simple hydrobro...Band structure and component content are the key factors for determining the activity of semiconductor heterojunction. In this study, a novel Bi_5O_7I/BiOBr_xI_(1-x)heterostructure was synthesized by a simple hydrobromic(HBr) acid etching method through transforming partial of Bi_5O_7I to Iàion doped Bi OBr(BiOBr_xI_(1-x)) at room temperature without adding extra dopant. Both the band structure and component content of Bi_5O_7I/BiOBr_xI_(1-x)alter with the additive HBr acid. The Bi_5O_7I/BiOBr_xI_(1-x)(S3.0) sample exhibits the best photocatalytic activity, 6 times higher than that of pure Bi_5O_7I, for the degradation of methyl orange under visible-light(λ > 420 nm). The activity enhancement of Bi_5O_7I/BiOBr_xI_(1-x)is primarily ascribed to the improved separation efficiency of photocharges, originated from the adjustable band structure and component content. The significant findings of this paper provide a facile way to construct highly efficient semiconductor heterojunction via playing the synergetic effect of adjustable band structure and component content for purifying organic pollutants in wastewater.展开更多
A modified hydrophilic penta-bismuth hepta-oxide nitrate （Bi5O7NO3） surface was synthesized via a precipitation method using TiO2 and Ag as modified agents. The synthesized product was characterized by different ana...A modified hydrophilic penta-bismuth hepta-oxide nitrate （Bi5O7NO3） surface was synthesized via a precipitation method using TiO2 and Ag as modified agents. The synthesized product was characterized by different analytical techniques. The removal efficiency was evaluated using mono- and di-sulphonated azo dyes as model pollutants. Different kinetic, isotherm and diffusion models were chosen to describe the adsorption process. X-ray photoelectron spectroscopy （XPS） results revealed no noticeable differences in the chemical states of modified adsorbent when compared to pure BisOTNO3; however, the presence of hydrophilic centres such as TiO2 and Ag developed positively charged surface groups and improved its adsorption performance to a wide range of azo dyes. Dyes removal was found to be a function of adsorbent dosage, initial dye concentration, solution pH and temperature. The reduction of Langmuir 1,2-mixed order kinetics to the second or first-order kinetics could be successfully used to describe the adsorption of dyes onto the modified adsorbent. Mass transfer can be described by intra-particle diffusion at a certain stage, but it was not the rate limiting step that controlled the adsorption process. Homogenous behavior of adsorbent surface can be explored by applying Langmuir isotherm to fit the adsorption data.展开更多
基金supported by the National Natural Science Foundation of China(51772118,51472005)State Key Laboratory of Structural Chemistry(20160014)+2 种基金Anhui Provincial Natural Science Foundation(1708085MB32)the Natural Science Foundation of Educational Committee of Anhui Province(gxyq ZD2016414,KJ2014B08)Innovation Team of Design and Application of Advanced Energetic Materials
文摘Band structure and component content are the key factors for determining the activity of semiconductor heterojunction. In this study, a novel Bi_5O_7I/BiOBr_xI_(1-x)heterostructure was synthesized by a simple hydrobromic(HBr) acid etching method through transforming partial of Bi_5O_7I to Iàion doped Bi OBr(BiOBr_xI_(1-x)) at room temperature without adding extra dopant. Both the band structure and component content of Bi_5O_7I/BiOBr_xI_(1-x)alter with the additive HBr acid. The Bi_5O_7I/BiOBr_xI_(1-x)(S3.0) sample exhibits the best photocatalytic activity, 6 times higher than that of pure Bi_5O_7I, for the degradation of methyl orange under visible-light(λ > 420 nm). The activity enhancement of Bi_5O_7I/BiOBr_xI_(1-x)is primarily ascribed to the improved separation efficiency of photocharges, originated from the adjustable band structure and component content. The significant findings of this paper provide a facile way to construct highly efficient semiconductor heterojunction via playing the synergetic effect of adjustable band structure and component content for purifying organic pollutants in wastewater.
文摘A modified hydrophilic penta-bismuth hepta-oxide nitrate （Bi5O7NO3） surface was synthesized via a precipitation method using TiO2 and Ag as modified agents. The synthesized product was characterized by different analytical techniques. The removal efficiency was evaluated using mono- and di-sulphonated azo dyes as model pollutants. Different kinetic, isotherm and diffusion models were chosen to describe the adsorption process. X-ray photoelectron spectroscopy （XPS） results revealed no noticeable differences in the chemical states of modified adsorbent when compared to pure BisOTNO3; however, the presence of hydrophilic centres such as TiO2 and Ag developed positively charged surface groups and improved its adsorption performance to a wide range of azo dyes. Dyes removal was found to be a function of adsorbent dosage, initial dye concentration, solution pH and temperature. The reduction of Langmuir 1,2-mixed order kinetics to the second or first-order kinetics could be successfully used to describe the adsorption of dyes onto the modified adsorbent. Mass transfer can be described by intra-particle diffusion at a certain stage, but it was not the rate limiting step that controlled the adsorption process. Homogenous behavior of adsorbent surface can be explored by applying Langmuir isotherm to fit the adsorption data.
