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: 91
- HTML全文浏览量: 100
- PDF下载量: 20
- 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

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 Shanxi, 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

图 1 （a）苯酚开环和矿化示意图^[8]，（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], (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，Al-TiO₂和TiO₂的（b）Ti 2p和（c）O 1S XPS谱图。由UPS谱图得到的Al-TiO₂和TiO₂（d）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. 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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