物理化学学报 >> 2017, Vol. 33 >> Issue (3): 590-601.doi: 10.3866/PKU.WHXB201611241

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水热法制备p-CoFe2O4/n-CdS及其光催化制氢性能

胡海龙1,王晟1,*(),侯美顺1,刘福生2,*(),王田珍1,李天龙1,董乾乾1,张鑫1   

  1. 1 南京工业大学化工学院,南京210009
    2 南京林业大学理学院化学与材料科学系,南京210037
  • 收稿日期:2016-08-01 发布日期:2017-03-07
  • 通讯作者: 王晟,刘福生 E-mail:w_angsheng@njtech.edu.cn;w_angshengnj@163.com;lfs039270@163.com
  • 基金资助:
    国家自然科学基金(50876047);江苏高校品牌专业建设工程项目(TAPP,PPZY2015A044);江苏省普通高校研究生科研创新计划项目(SJLX15-0346)

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)

摘要:

水热法制备了系列p-n复合半导体p-CoFe2O4/n-CdS。采用X射线衍射(XRD)、冷场发射扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-Vis DRS)、透射电镜(TEM)和电化学工作站等对制得的光催化剂进行了结构和性能表征。研究了p-CoFe2O4/n-CdS复合光催化剂的可见光催化制氢性能及光腐蚀性能,并对光催化活性的提高、反应条件的影响及光腐蚀行为的抑制机理进行了分析。结果表明:由于CoFe2O4和CdS两种窄带隙半导体复合增加了光吸收率;CdS独特的树形结构以及CoFe2O4和CdS二者复合所产生的能带交迭和内建电场的三重作用,促进了电子从CoFe2O4向CdS的迁移,减少电子-空穴对复合的概率,增强了光催化活性。光生电子-空穴对的分离效率以及光催化剂表面吸附性能都对产氢速率有重要影响。CH3OH水溶液的pH对光催化剂中光生电子-空穴对的分离效率以及光催化剂表面吸附性能都有影响。牺牲剂CH3OH的加入以及CoFe2O4和CdS二者复合所产生的能带交迭和内建电场的作用都对CdS的光腐蚀起了抑制作用,后者的抑制效果更好。

关键词: CoFe2O4, CdS, 光催化, 制氢, 光腐蚀

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