title: Enhanced photoelectrocatalytic degradation of ammonia by in situ photoelectrogenerated active chlorine on TiO2nanotube electrodes.
abstract: TiO2nanotube (TiNT) electrodes anodized in fluorinated organic solutions were successfully prepared on Ti sheets. Field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) were performed to characterize the TiNT electrodes. The linear voltammetry results under irradiation showed that the TiNT electrode annealed at 450°C presented the highest photoelectrochemical activity. By combining photocatalytic with electrochemical process, a significantly synergetic effect on ammonia degradation was observed with Na2SO4as supporting electrolyte at pH10.7. Furthermore, the photoelectrocatalytic efficiency on the ammonia degradation was greatly enhanced in presence of chloride ions without the limitation of pH. The degradation rate was improved by 14.8 times reaching 4.98×10-2min-1at pH10.7 and a faster degradation rate of 6.34×10-2min-1was obtained at pH3.01. The in situ photoelectrocatalytic generated active chlorine was proposed to be responsible for the improved efficiency. On the other hand, an enhanced degradation of ammonia using TiNT electrode fabricated in fluorinated organic solution was also confirmed compared to TiNT electrode anodized in fluorinated water solution and TiO2film electrode fabricated by sol-gel method. Finally, the effect of chloride concentration was also discussed.
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address: xiaoshuhu@126.com.
authors.forename: Shuhu
authors.initials: S
authors.lastname: Xiao
authors.affiliation: School of Chemistry and Chemical Engineering, Henan University of Technology, Zhengzhou, Henan 450001, China.
authors.forename: Dongjin
authors.initials: D
authors.lastname: Wan
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Kun
authors.initials: K
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China.
authors.forename: Hongbin
authors.initials: H
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address: pjf1995@163.com.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Peng
mesh_terms: D000641:Ammonia; D002713:Chlorine / Q000737:chemistry*; D055664:Electrochemical Techniques; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D008956:Models, Chemical; D043942:Nanotubes / Q000737:chemistry*; D055668:Photochemical Processes; D014025:Titanium / Q000737:chemistry*
chemical_list: C009495:titanium dioxide; D002713:Chlorine; D000641:Ammonia; D014025:Titanium
keywords: Ammonia; Enhanced degradation; Photoelectrocatalytic process; TiO(2) nanotube electrodes