Acta Chimica Sinica ›› 2021, Vol. 79 ›› Issue (4): 506-512.DOI: 10.6023/A20120575 Previous Articles     Next Articles



何利蓉1, 唐笑1,*(), 张灵1, 李艳虹1, 相国涛1, 周贤菊1, 凌发令1, 姚璐1, 蒋浩1   

  1. 1 重庆邮电大学理学院 重庆 400045
  • 投稿日期:2020-12-19 发布日期:2021-03-12
  • 通讯作者: 唐笑
  • 基金资助:
    重庆市留学人员创新支持计划重点项目(CX2017023); “成渝地区双城经济圈建设”科技创新项目(KJCX2020028); 国家自然科学基金青年基金(12004061); 重庆市教育委员会科学技术研究重点项目(KJZD-K201800602); 重庆自然科学基金面上项目(cstc2019jcyj-msxmX0525)

Study on Photoelectrochemical Properties of Colorful Carbon Nitrides Synthesized in Liquid-Phase

Lirong He1, Xiao Tang1,*(), Ling Zhang1, Yanhong Li1, Guotao Xiang1, Xianju Zhou1, Faling Ling1, Lu Yao1, Hao Jiang1   

  1. 1 School of Science, Chongqing University of Posts and Telecommunications, Chongqing 400045, China
  • Received:2020-12-19 Published:2021-03-12
  • Contact: Xiao Tang
  • About author:
  • Supported by:
    Venture & Innovation Support Program for Chongqing Oversea Returnee(CX2017023); Construction of Double City Economic Circle in Chengdu Chongqing Region Scientific and Technological Innovation Project(KJCX2020028); National Natural Science Foundation of China(12004061); Science and Technology Research Program of Chongqing Municipal Education(KJZD-K201800602); Chongqing Natural Science Foundation(cstc2019jcyj-msxmX0525)

Reducing the band gap value and obtaining an ordered two-dimensional microstructure are crucial to improving the photoelectrochemical performance of carbon nitrides. By adjusting the ratio of urea and citric acid and ripening the precursor at the room temperature, we synthesize the carbon nitride materials with different colors of orange, green and blue. The resultant blue sample has a narrowed band gap of 1.74 eV and the strong absorption to the light in 550~700 nm wavelength range. The photoelectrochemical solar cell is fabricated using the synthesized carbon nitrides as light absorber, TiO2 as electron transporter and I3/I as the redox shuttle in electrolyte. The orange carbon nitride has typical photoelectric conversion performance with Jsc=0.65 mA•cm–2, Voc=530 mV and ff=0.64. The blue carbon nitride has obvious enhanced Jsc of 1.03 mA•cm–2 owing to the obvious enhanced visible light absorption, while the deeply decreased ff of 0.33. The cyclic voltammetry tests demonstrate the electrode reaction properties of the fabricated carbon nitride-based cell under illumination. It turns out that the cell based on the blue carbon nitride has obvious photo-induce pseudocapacitive behavior with an area specific capacitance of 4.9 mF•cm–2. TEM (Transmission electron microscope), XRD (X-ray diffraction), FTIR (Fourier transform infrared spectroscopy) and XPS (X-ray photoelectron spectroscopy) reveal the microstructure characteristics of the colored carbon nitrides. The orange one is carbon nitride quantum dots with the particle size less than 10 nm. The blue one is a carbon nitride polymer containing graphite domains with oxidized boundaries, forming three-dimensional porous structure constructed by an ordered two-dimensional network. The green one has a mixture microstructure as well as the medium photoelectrochemical properties between the former two, which are both photoelectric conversion and photo-induced charge storage performance.

Key words: carbon nitrides, photoelectric conversion, charge storage, pseudo-capacitance, solar energy