Superoxide radical-mediated photocatalytic oxidation of phenolic compounds over Ag+/TiO2: Influence of electron donating and withdrawing substituents

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	Superoxide radical-mediated photocatalytic oxidation of phenolic compounds over Ag+/TiO2: Influence of electron donating and withdrawing substituents
	Xiao, Jiadong 1,2; Xie, Yongbing 1; Han, Qingzhen 3; Cao, Hongbin 1,4; Wang, Yujiao 5; Nawaz, Faheem 1,2; Duan, Feng 1,2
刊名	JOURNAL OF HAZARDOUS MATERIALS
	2016-03-05
卷号	304 期号:MAR 页码:126-133
关键词	TiO2 Photocatalysis Substituent Phenolic compounds Superoxide radical Mechanism
ISSN号	0304-3894
英文摘要	A comparative study was constructed to correlate the electronic property of the substituents with the degradation rates of phenolic compounds and their oxidation pathways under UV with Ag+/TiO2 suspensions. It was verified that a weak electron withdrawing substituent benefited photocatalytic oxidation the most, while an adverse impact appeared when a substituent was present with stronger electron donating or withdrawing ability. The addition of p-benzoquinone dramatically blocked the degradation, confirming superoxide radicals (O-center dot(2)-) as the dominant photooxidant, rather than hydroxyl radicals, singlet oxygen or positive holes, which was also independent of the substituent. Hammett relationship was established based on pseudo-first-order reaction kinetics, and it revealed two disparate reaction patterns between center dot O-2(-) and phenolic compounds, which was further verified by the quantum chemical computation on the frontier molecular orbitals and Mulliken charge distributions of center dot O-2(-) and phenolic compounds. It was found that electron donating group (EDG) substituted phenols were more likely nucleophilically attacked by center dot O-2(-), while center dot O-2(-) preferred to electrophilically assault electron withdrawing group (EWG) substituted phenols. Exceptionally, electrophilic and nucleophilic attack by center dot O-2(-) could simultaneously occur in p-chlorophenol degradation, consequently leading to its highest rate constant. Possible reactive positions on the phenolic compounds were also detailedly uncovered. (C) 2015 Elsevier B.V. All rights reserved.
WOS标题词	Science & Technology ; Technology ; Life Sciences & Biomedicine
类目[WOS]	Engineering, Environmental ; Engineering, Civil ; Environmental Sciences
研究领域[WOS]	Engineering ; Environmental Sciences & Ecology
关键词[WOS]	VISIBLE-LIGHT IRRADIATION ; TIO2 AQUEOUS SUSPENSIONS ; DOPED TIO2 ; HYDROTHERMAL SYNTHESIS ; TITANIUM-DIOXIDE ; METAL-IONS ; DEGRADATION ; CARBON ; 4-CHLOROPHENOL ; PHOTODEGRADATION
收录类别	SCI
语种	英语
WOS记录号	WOS:000367699200015
内容类型	期刊论文
源URL	[http://ir.ipe.ac.cn/handle/122111/20259]
专题	过程工程研究所_多相复杂系统国家重点实验室
作者单位	1.Chinese Acad Sci, Beijing Engn Res Ctr Proc Pollut Control, Key Lab Green Proc & Engn,Inst Proc Engn, Natl Engn Lab Hydromet Cleaner Prod Technol, Beijing 100190, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.Chinese Acad Sci, Inst Proc Engn, State Key Lab Multiphase Complex Syst, Beijing 100190, Peoples R China 4.Collaborat Innovat Ctr Chem Sci & Engn Tianjin, Tianjin 300072, Peoples R China 5.Univ Sci & Technol Beijing, Dept Chem & Biomed Engn, Beijing, Peoples R China
推荐引用方式 GB/T 7714	Xiao, Jiadong,Xie, Yongbing,Han, Qingzhen,et al. Superoxide radical-mediated photocatalytic oxidation of phenolic compounds over Ag+/TiO2: Influence of electron donating and withdrawing substituents[J]. JOURNAL OF HAZARDOUS MATERIALS,2016,304(MAR):126-133.
APA	Xiao, Jiadong.,Xie, Yongbing.,Han, Qingzhen.,Cao, Hongbin.,Wang, Yujiao.,...&Duan, Feng.(2016).Superoxide radical-mediated photocatalytic oxidation of phenolic compounds over Ag+/TiO2: Influence of electron donating and withdrawing substituents.JOURNAL OF HAZARDOUS MATERIALS,304(MAR),126-133.
MLA	Xiao, Jiadong,et al."Superoxide radical-mediated photocatalytic oxidation of phenolic compounds over Ag+/TiO2: Influence of electron donating and withdrawing substituents".JOURNAL OF HAZARDOUS MATERIALS 304.MAR(2016):126-133.