正负电荷关联转移促进的光催化低浓度苯酚矿化

高树功; 魏旭晖; 刘海峰; 方峣; 贾昆; 向后奎; 陈加藏

doi:10.19906/j.cnki.JFCT.2023035

正负电荷关联转移促进的光催化低浓度苯酚矿化

doi: 10.19906/j.cnki.JFCT.2023035

高树功^{1, 2,},
魏旭晖^{1, 2,},
刘海峰^{1, 2,},
方峣^1,,
贾昆^{1, 2,},
向后奎^1,,
陈加藏^{1, 2, ,}

1.
中国科学院山西煤炭化学研究所煤转化国家重点实验室, 山西太原 030001
2.
中国科学院大学, 北京 100049

基金项目: 国家自然科学基金(22172185，21773285)资助

详细信息

通讯作者:
Tel: 0351-4845811，E-mail: chenjiazang@sxicc.ac.cn

中图分类号: O649.4
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- 文章访问数: 238
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- 被引次数: 0
出版历程
- 收稿日期: 2023-04-14
- 修回日期: 2023-04-20
- 录用日期: 2023-04-20
- 网络出版日期: 2023-05-06
- 刊出日期: 2024-01-09

Photocatalytic mineralization of low concentration phenol facilitated by transfer of positive and negative charges correlation

GAO Shugong^{1, 2
,},
WEI Xuhui^{1, 2
,},
LIU Haifeng^{1, 2
,},
FANG Yao^1
,,
JIA Kun^{1, 2
,},
XIANG Houkui^1
,,
CHEN Jiazang^{1, 2
, ,}

1.
State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001, China
2.
University of Chinese Academy of Sciences, Beijing 100049, China

Funds: The project was supported by the National Natural Science Foundation of China (22172185，21773285)

摘要

摘要: 光催化矿化难降解污染物（如苯酚）需要羟基自由基（·OH）进行开环反应。本研究通过Al掺杂削弱了TiO₂表面对氧物种的吸附，有效促进光致·OH的生成。同时，Al元素还能降低TiO₂的导带能级，继而降低半导体-助催化剂界面电子转移势垒而促进还原半反应。由于正负电荷的强关联性，还原半反应中电子的快速转移可提高半导体内空穴浓度，加快·OH的生成。此外，通过将催化剂固定在反应器的光入射内壁，还能避免由污染物竞争光吸收所引起的光子损失。基于这些优点，有望实现废水中低浓度苯酚的高效光催化矿化。
- 苯酚 /
- 光催化 /
- 矿化 /
- 界面电子转移 /
- TiO₂
Abstract: Photocatalytic mineralization of recalcitrant contaminants such as phenol requires hydroxyl radicals (·OH) for ring-opening reactions. Here, we weaken the adsorption of oxygen species on TiO₂ surface by Al doping, which can effectively promote the photoinduced ·OH generation. Besides, Al doping can downshift the conduction band of TiO₂. The resulted potential barrier lowering can promote semiconductor-cocatalyst interfacial electron transfer for the reduction half-reaction. Due to the strong correlation between positive and negative charges, the rapid transfer of electrons in the reduction half-reaction can also increase the concentration of holes in the semiconductor and promote the generation of ·OH. By immobilizing the photocatalyst on the light-incident inner wall of the reactor, it can avoid the competitive light absorption by the contaminant. By these virtues, efficient photocatalytic mineralization of low-concentration phenol in wastewater can be realized.
- phenol /
- photocatalytic /
- mineralization /
- interfacial electron transfer /
- TiO₂

HTML全文

FIG. 2883. FIG. 2883.

FIG. 2883. FIG. 2883.

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图 1 （a）苯酚开环和矿化示意图^[8]（改编自Elsevier）；（b）光催化反应的基本过程及其时间尺度^[10]（绿线和红线分别代表正副反应过程）；（c）正负电荷内在关联性

Figure 1 (a) Schematic diagram for ring-opening and mineralization of phenol^[8] (Adapted from Elsevier); (b) The basic process of photocatalytic reaction and its timescale ^[10] (The green and red arrows respectively represent the forward and side reactions); (c) Strong correlation between positive and negative charges

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图 2 Al掺杂前后的（a）XRD谱图，（b）UV-vis吸收光谱图，（c）TiO₂及（d）Al-TiO₂的SEM照片，（e）Al-TiO₂的高角环形暗场像及元素分析（图中标尺长度为200 nm）

Figure 2 (a) XRD patterns; (b) UV-vis absorption spectra; (c), (d) SEM images of Al-TiO₂ and TiO₂; (e) the high angle annular dark field image and elemental mappings of Al-TiO₂ (the scale bar shown in elemental mappings is 200 nm)

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图 3 （a）Al-TiO₂的Al 2p XPS谱图；（b）和（c）Al-TiO₂和TiO₂的Ti 2p和O 1s XPS谱图；（d）由UPS谱图得到的Al-TiO₂和TiO₂功函数和（e）结合能及（f）能带示意图

Figure 3 (a) Al 2p XPS spectrum of Al-TiO₂; (b) Ti 2p and (c) O 1s XPS spectra of Al-TiO₂ and TiO₂; (d) Work function; (e) Binding energy; (f) The band alignment can be obtained from UPS spectra of Al-TiO₂ and TiO₂

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图 4 TiO₂和Al-TiO₂的RRDE行为，盘电流和环电流分别反映·OH的生成和捕获

Figure 4 The RRDE behaviors of TiO₂ and Al-TiO₂ (In this electrode configuration, the disk and ring currents respectively reflect the generation and capture of ·OH)

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图 5 分散于100 mL水杨酸溶液中的Al-TiO₂和TiO₂在光照下DHBA的产率以及根据捕获率所得的·OH的产率

Figure 5 The generation rate of DHBA over Al-TiO₂ and TiO₂ dispersed in 100 mL salicylic acid solution under irradiation, and the generation rate of ·OH can be evaluated from the generated DHBA with consideration of the capture ratio

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图 6 Al-TiO₂和TiO₂在PBS溶液中的（a）水氧化和（b）氧还原反应中的伏安行为曲线

Figure 6 The voltammetry behaviors of Al-TiO₂ and TiO₂ electrodes in (a) water oxidation and (b) oxygen reduction reaction (For the oxygen reduction reaction, the measurements were conducted when the rotating disk electrode was rotating at a speed of 1600 r/min)

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图 7 （a）Al-TiO₂、TiO₂、Pt/Al-TiO₂和Pt/TiO₂电极在PBS溶液通氩条件下的OCP行为，以及由此获得的（b）τ_OCP-(dual)及（c）τ_SC；（d）导带的下移降低SC界面电子转移势垒高度示意图

Figure 7 (a) OCP behaviors of Al-TiO₂, TiO₂, Pt/Al-TiO₂, and Pt/TiO₂ electrodes in argon bubbled PBS solution; The time constants including (b) τ_OCP-(dual) and (c) τ_SC can be obtained from the OCP curves; (d) Schematic diagram shows that the downshift of conduction band lowers the potential barrier for SC interfacial electron transfer

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图 8 Al-TiO₂、TiO₂、Pt/Al-TiO₂和Pt/TiO₂在PBS溶液通氧条件下的（a）OCP行为，以及由此获得的（b）τ_OCP-(dual)及（c）τ_SC

Figure 8 (a) OCP behaviors, of Al-TiO₂, TiO₂, Pt/Al-TiO₂, and Pt/TiO₂ in oxygen bubbled PBS solution; the time constants such as (b) τ_OCP-(dual) and (c) τ_SC can be obtained from the OCP decay

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图 9 （a）TiO₂光电化学体系在不同电势下产生的光生电流密度；（b）·OH的生成量和光生电子的收集量

Figure 9 (a) The photocurrent density of TiO₂ photochemical system under different potential; (b) The generation of ·OH and the number of collected photogenerated electrons

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图 10 （a）光催化苯酚矿化固定床反应示意图；（b）Pt/Al-TiO₂固定床和浆态床反应速率对比；（c）Al-TiO₂、TiO₂、Pt/Al-TiO₂和Pt/TiO₂光催化剂对苯酚（COD, 100 mg/L）光催化矿化

Figure 10 (a) Schematic diagram for fixed bed reactor of photocatalytic phenol mineralization; (b) Comparison of Pt/Al-TiO₂ reaction rate between fixed bed and slurry suspension; (c) The photocatalytic mineralization of phenol (COD,100 mg/L) over Al-TiO₂, TiO₂, Pt/Al-TiO₂, and Pt/TiO₂ photocatalysts

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