Acta Phys. -Chim. Sin. ›› 2017, Vol. 33 ›› Issue (3): 590-601.doi: 10.3866/PKU.WHXB201611241

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Preparation of p-CoFe2O4/n-CdS by Hydrothermal Method and Its Photocatalytic Hydrogen Production Activity

Hai-Long HU1,Sheng WANG1,*(),Mei-Shun HOU1,Fu-Sheng LIU2,*(),Tian-Zhen WANG1,Tian-Long LI1,Qian-Qian DONG1,Xin ZHANG1   

  1. 1 College of Chemical Engineering, Nanjing Tech University, Nanjing 210009, P. R. China
    2 Department of Chemistry and Materials Science, College of Science, Nanjing Forestry University, Nanjing 210037, P. R. China
  • Received:2016-08-01 Published:2017-03-07
  • Contact: Sheng WANG,Fu-Sheng LIU E-mail:w_angsheng@njtech.edu.cn;w_angshengnj@163.com;lfs039270@163.com
  • Supported by:
    the National Natural Science Foundation of China(50876047);Top-notch Academic Programs Project of Jiangsu Higher Education Institutions, China(TAPP,PPZY2015A044);Scientific Research Innovation Program of Graduate in Colleges and Universities of Jiangsu Province, China(SJLX15-0346)

Abstract:

A series of p-n coupled p-CoFe2O4/n-CdS photocatalysts were prepared by a hydrothermal method. The structure and properties of p-CoFe2O4/n-CdS were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS), transmission electron microscopy (TEM) and the electrochemical workstation. The photocatalytic activities of p-CoFe2O4/nCdS were evaluated by photocatalytic hydrogen production under visible light irradiation. The effects of photocorrosion of CdS in p-CoFe2O4/n-CdS were investigated by analyzing the cadmium concentration of the supernatant collected after the photocatalytic reactions. The mechanism of the catalytic activity enhancement, effects of reaction conditions on the photocatalytic hydrogen evolution rate, and cadmium leakage resistance are discussed. The results show that p-CoFe2O4/n-CdS exhibits higher photocatalytic activity attributed to stronger light absorption by the two types of narrow band gap semiconductor CoFe2O4 and CdS, the formation of a "forest-like" structure of CdS and rapid electron transfer from CoFe2O4 to CdS, resulting from band overlap and an inner electric field in p-CoFe2O4/n-CdS, to reduce the probability of electron/hole pair recombination. Both the separation efficiency of photo-generated electron-hole pairs and the adsorption performance of photocatalysts had an important influence on the hydrogen production rate. The pH of the CH3OH aqueous solution influenced the separation efficiency of photogenerated electron-hole pairs and the adsorption properties of the photocatalyst. p-CoFe2O4/n-CdS also exhibited resistance against cadmium leakage under light irradiation owing to the presence of methanol in the reaction solution, the band overlap of the semiconductors and the inner electric field in p-CoFe2O4/n-CdS. The band overlap and inner electric field had the most influence on the cadmium leakage resistance.

Key words: CoFe2O4, CdS, Photocatalysis, Hydrogen production, Photocorrosion

MSC2000: 

  • O643