Chinese Journal of Catalysis ›› 2018, Vol. 39 ›› Issue (3): 413-420.DOI: 10.1016/S1872-2067(17)62993-0

• Communications • Previous Articles     Next Articles

Efficient photoelectrocatalytic CO2 reduction by cobalt complexes at silicon electrode

Liangfeng Chena,b, Zhuo Wanga, Peng Kanga,b   

  1. a Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China;
    b University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2017-10-15 Revised:2017-11-17 Online:2018-03-18 Published:2018-03-10
  • Contact: 10.1016/S1872-2067(17)62993-0
  • Supported by:

    This work was supported by the National Key R&D Program of China (2016YFB0600901) and the Strategic Priority Research Program of the Chinese Academy of Sciences (XDB17030300).

Abstract:

Two homogeneous photoelectrocatalytic systems composed of simple polypyridyl Co complexes[Co(tpy)2](PF6)2 and[Co(bpy)3](PF6)2 as electrocatalysts and a Si wafer as the photoelectrode were used for combined photoelectrochemical reduction of CO2 to CO. A high photocurrent density of 1.4 mA/cm2 was observed for the system with the[Co(tpy)2](PF6)2 catalyst and a photovoltage of 400 mV was generated. Faradaic efficiencies of CO were optimized to 83% and 94% for the[Co(tpy)2](PF6)2 and[Co(bpy)3](PF6)2 complexes, respectively, in acetonitrile solution with 10% methanol (volume fraction, same below) as a protic additive. Addition of 2% water volume fraction induced a large amount of non-specific H2 evolution by the Si photoelectrode.

Key words: Photoelectrocatalytic system, Molecular electrocatalyst, Carbon dioxide reduction, Carbon monoxide, Polypyridine complex