Chinese Journal of Catalysis ›› 2020, Vol. 41 ›› Issue (3): 514-523.DOI: 10.1016/S1872-2067(19)63497-2

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Co-MOF as an electron donor for promoting visible-light photoactivities of g-C3N4 nanosheets for CO2 reduction

Qiuyu Chena, Sijia Lia, Hongyi Xua, Guofeng Wanga, Yang Qua, Peifen Zhub, Dingsheng Wangc   

  1. a Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education, School of Chemistry and Materials Science, Heilongjiang University, Harbin 150080, Heilongjiang, China;
    b Department of Physics and Engineering Physics, The University of Tulsa, Tulsa, OK 74104, USA;
    c Department of Chemistry, Tsinghua University, Beijing 100084, China
  • Received:2019-07-15 Revised:2019-08-23 Online:2020-03-18 Published:2019-11-19
  • Supported by:
    This work was supported by the National Natural Science Foundation of China (21871079,21501052), and the Outstanding Youth Project of Natural Science Foundation of Heilongjiang Province (YQ2019B006).

Abstract: A possible mechanism for boosting the visible-light photoactivities of graphitic carbon nitride (g-C3N4) nanosheets for CO2 reduction via coupling with the electron donor Co-metal-organic framework (MOF) is proposed in this study. Specifically, Co-MOF as an electron donor is capable of transferring the photogenerated electrons in the lowest unoccupied molecular orbital (LUMO) to the conduction band of g-C3N4 to facilitate charge separation. As expected, the prepared Co-MOF/g-C3N4 nanocomposites display excellent visible-light-driven photocatalytic CO2 reduction activities. The CO production rate of 6.75 µmol g-1 h-1 and CH4 evolution rate of 5.47 µmol g-1 h-1 are obtained, which are approximately 2 times those obtained with the original g-C3N4 under the same conditions. Based on a series of analyses, it is shown that the introduction of Co-MOF not only broadens the range of visible-light absorption but also enhances the charge separation, which improves the photocatalytic activity of g-C3N4 to a higher level. In particular, the hydroxyl radical (·OH) experiment was operated under 590 nm (single-wavelength) irradiation, which further proved that the photogenerated electrons in the LUMO of Co-MOF can successfully migrate to g-C3N4. This work may provide an important strategy for the design of highly efficient g-C3N4-based photocatalysts for CO2 reduction.

Key words: Co-MOF, g-C3N4 nanosheets, Charge separation, Visible-light photoactivity, Photocatalytic CO2 conversion