Environment-Friendly Carbon Quantum Dots/ZnFe2O4Photocatalysts: Characterization, Biocompatibility, and Mechanisms for NO Removal.
A highly efficient and environmentally-friendly oxidation process is always desirable for air purification. This study reported a novel carbon quantum dots (CQDs)/ZnFe2O4composite photocatalyst for the first time through a facile hydrothermal process. The CQDs/ZnFe2O4(15 vol %) composite demonstrates stronger transient photocurrent response, approximately 8 times higher than that of ZnFe2O4, indicating superior transfer efficiency of photogenerated electrons and separation efficiency of photogenerated electron-hole pairs. Compared with pristine ZnFe2O4nanoparticles, CQDs/ZnFe2O4displayed enhanced photocatalytic activities on gaseous NOxremoval and high selectivity for nitrate formation under visible light (λ > 420 nm) irradiation. Electron spin resonance analysis and a series of radical-trapping experiments showed that the reactive species contributing to NO elimination were ·O2-and ·OH radicals. The possible mechanisms were proposed regarding how CQDs improve the photocatalytic performance of ZnFe2O4. The CQDs are believed to act as an electron reservoir and transporter as well as a powerful energy-transfer component during the photocatalysis processes over CQDs/ZnFe2O4samples. Furthermore, the toxicity assessment authenticated good biocompatibility and low cytotoxity of CQDs/ZnFe2O4. The results of this study indicate that CQDs/ZnFe2O4is a promising photocatalyst for air purification.
Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences , Xi'an 710061, China.|State Key Lab of Loess and Quaternary Geology (SKLLQG), Institute of Earth Environment, Chinese Academy of Sciences , Xi'an 710061, China.
Yu
0000-0003-3334-4849
Y
Huang
Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences , Xi'an 710061, China.
Yanling
Y
Liang
Department of Environmental Science and Engineering, Xi'an Jiaotong University , Xi'an 710049, China.
Yongfang
Y
Rao
Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences , Xi'an 710061, China.
Dandan
D
Zhu
Key Laboratory of Aerosol Chemistry and Physics, Institute of Earth Environment, Chinese Academy of Sciences , Xi'an 710061, China.|State Key Lab of Loess and Quaternary Geology (SKLLQG), Institute of Earth Environment, Chinese Academy of Sciences , Xi'an 710061, China.
Jun-Ji
JJ
Cao
Department of Environmental Science and Engineering, Xi'an Jiaotong University , Xi'an 710049, China.
Zhenxing
Z
Shen
Department of Science and Environmental Studies, The Education University of Hong Kong , Hong Kong, China.
Wingkei
W
Ho
Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University , Hung Hom, Hong Kong, China.
Shun Cheng
SC
Lee
D002244:Carbon; D002384:Catalysis; D008027:Light; D010084:Oxidation-Reduction; D045663:Quantum Dots
D002244:Carbon