J. Mater. Sci. Technol. ›› 2023, Vol. 165: 85-93.DOI: 10.1016/j.jmst.2023.04.043

• Research Article • Previous Articles     Next Articles

An ultrafast carrier dynamics system from oxygen vacancies modified SnO2 QDs and Zn2SnO4 heterojunction for deeply photocatalytic oxidation of NO

Yuhan Lia,b, Min Zhanga, Bangfu Chena, Ping Ouyanga, Youyu Duanc,*, Kangle Lvd, Fan Donga,*   

  1. aEngineering Research Center for Waste Oil Recovery Technology and Equipment, Ministry of Education, Chongqing Key Laboratory of Catalysis and New Environmental Materials, Chongqing Technology and Business University, Chongqing 400067, China;
    bNanchang Institute of Technology, Nanchang 33044, China;
    cCollege of Physics and Center of Quantum Materials and Devices, Chongqing University, Chongqing 401331, China;
    dKey Laboratory of Resources Conversion and Pollution Control of the State Ethnic Affairs Commission, College of Resources and Environmental Science, South-Central Minzu University, Wuhan 430074, China
  • Received:2023-02-07 Revised:2023-03-30 Accepted:2023-04-16 Published:2023-12-01 Online:2023-06-07
  • Contact: *E-mail addresses: . youyuduan@cqu.edu.cn (Y. Duan), dongfan@uestc.edu.cn (F. Dong)

Abstract: Deeply photocatalytic oxidation of NO-to-NO3- holds great promise for alleviating NOx pollution. The major challenge of NO photo-oxidation is the highly in-situ generated NO2 concentration, and the formation of unstable nitrate species causes desorption to release NO2. In this study, SnO2 quantum dots and oxygen vacancies co-modified Zn2SnO4 (ZSO-SnO2-OVs) were prepared by a one-step hydrothermal procedure, the NO photo-oxidation was investigated by a combination of solid experimental and theoretical support. Impressively, spectroscopic measurements indicate that fast carrier dynamics can be achieved due to the electron transfer efficiency of ZSO-SnO2-OVs reaching 99.99%, far outperforming the counterpart and previously reported photocatalysts. During NO oxidation, molecular NO/O2 and H2O are efficiently adsorbed/activated around OVs and SnO2 QDs, respectively. In-situ infrared measurements and calculated electron localized function disclose two main findings: (1) richly electrons enable NO promptly form NO- instead of toxic NO2 or NO+; (2) the generation of stable and undecomposed bidentate NO3- rather than bridging or monodentate one benefits the deep oxidation of NO via shifting reaction sites from O terminals for original ZSO to Sn ones for ZSO-SnO2-OVs. The synergistic action of SnO2 QDs and OVs positively contributes to the NO oxidation performance enhancement (60.6%, 0.1 g of sample) and high selectivity of NO to NO3- (99.2%). Results from this study advance the mechanistic understanding of NO photo-oxidation and its selectivity to NO3- over photocatalysts.

Key words: Zn2SnO4, Modification, NO photo-oxidation, Charge transfer efficiency, Reaction mechanism