光催化
光化学
电子顺磁共振
光降解
可见光谱
激进的
吸附
二氧化钛
氧气
材料科学
羟基自由基
量子产额
氧化物
化学
催化作用
荧光
有机化学
冶金
物理
量子力学
光电子学
核磁共振
作者
Yan Wang,Xiaoqing He,Peng Gao,Feng Li,Liqiu Zhang
标识
DOI:10.1016/j.envres.2024.118301
摘要
Limited utilization of photogenerated charge carriers in titanium dioxide under visible light have hinder its application development. To address this challenge, a novel N-doped carbon quantum dots (N-CQDs) and oxygen vacancies (OVs) synergistically decorated on TiO2 (P25) was synthesized through a facile one-step hydrothermal method. Under visible light irradiation, the first order reaction rate constants of formaldehyde (HCHO) photocatalytic oxidation by OVs-TiO2 and N-CQDs/OVs-TiO2 was significantly higher than that of pristine P25, with 10.1 and 16.7 folds increase, respectively. Characterization results confirmed the generation of OVs on the surface of N-CQDs/TiO2 composite. The optical and electrochemical experiments suggested the electron capture center effect of OVs and the properties of N-CQDs in unique up-converted photoluminescence, efficient charge separation, as well as significant adsorption in visible light region. In addition, the work function also clarified that photoelectrons could transfer from N-CQDs to OVs-TiO2. Furthermore, different relative humidity and electron paramagnetic resonance (EPR) experiments demonstrated that the hydroxyl radical (•OH) was the dominant reactive radical in HCHO photodegradation. The •O2− could also enhance the photodegradation efficiency of HCHO. This work provides an in-depth understanding on the complementary roles of N-CQDs and OVs and is helpful for designing metallic oxide photocatalysts for volatile organic compounds removal.
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