Experimental evidences and theoretical calculations on phenanthrene degradation in a solar-light-driven photocatalysis system using silica aerogel supported TiO2 nanoparticles: Insights into reactive sites and energy evolution

被引：62

作者：

Ji, Haodong ^{[1
,2
]}

Liu, Wen ^{[1
,2
]}

Sun, Fengbin ^{[1
,2
]}

Huang, Taobo ^{[1
]}

Chen, Long ^{[1
]}

Liu, Yue ^{[1
]}

Qi, Juanjuan ^{[1
]}

Xie, Chenghan ^{[1
]}

Zhao, Dongye ^{[3
]}

机构：

[1] Peking Univ, Key Lab Water & Sediment Sci, Minist Educ, Coll Environm Sci & Engn, Beijing 100871, Peoples R China

[2] Peking Univ, State Environm Protect Key Lab All Mat Fluxes Riv, Beijing 100871, Peoples R China

[3] Auburn Univ, Dept Civil & Environm Engn, Environm Engn Program, Auburn, AL 36849 USA

来源：

CHEMICAL ENGINEERING JOURNAL | 2021年 / 419卷

基金：

中国国家自然科学基金; 中国博士后科学基金;

关键词：

Photocatalysis; Reactive sites; Density functional theory; Organic pollutants; TiO2; nanoparticles; EFFICIENT DEGRADATION; TITANATE NANOTUBES; DOPED TIO2; ADSORPTION; ANATASE; WATER; COMPOSITE; PHOTOOXIDATION; HYDROCARBONS; MECHANISMS;

D O I：

10.1016/j.cej.2021.129605

中图分类号：

X [环境科学、安全科学];

学科分类号：

08 ; 0830 ;

摘要：

Quantitative identification on reactive sites of target organic molecule during photocatalysis can help to get deep insight into the pollutant degradation pathway and energy evolution process. In this study, a new class of silica aerogel supported TiO2 (TiO2/SiO2) photocatalysts were fabricated via a two-step approach, and applied for adsorption and photocatalytic degradation of phenanthrene. Anatase crystalline structure was formed upon calcination at 400 and 600 degrees C, while mixed crystal interphases of anatase and rutile were generated at 800 degrees C (anatase:rutile = 0.67:0.33). The higher calcination temperature resulted in better crystallinity of TiO2, higher photocatalytic activity, and reduced adsorption affinity toward phenanthrene. TiO2/SiO2-800 (TiO2/SiO2 calcined at 800 degrees C) showed minimal phenanthrene uptake (similar to 5.2%) but the strongest photocatalytic activity, and it was able to completely degrade phenanthrene within 3 h. The SiO2 aerogel component in the composite enabled the pre-concentration of phenanthrene on the photoactive sites, while the nanoscale mixed-phases of anatase and rutile of TiO2/SiO2-800 act as an efficient transfer medium for photo-induced charge carriers. Moreover, the formed Ti-O-Si linkage in TiO2/SiO2-800 induced formation of Ti3+ under solar light irradiation, promoting photoexcited electron trap and separation of electron-hole pairs. Based on the degraded phenanthrene intermediates/products, theoretical calculations according to the density functional theory (DFT) reveal that the atoms of phenanthrene with high electrophilic Fukui index (f(-)) are the most reactive sites towards the radicals. Potential energy surface profile for phenanthrene degradation further reveals the intermediates energy evaluation via radicals attack.

引用

页数：14