影像科学与光化学 ›› 1992, Vol. 10 ›› Issue (3): 237-242.DOI: 10.7517/j.issn.1674-0475.1992.03.237

• 研究论文 • 上一篇    下一篇

光催化乙醇水溶液脱氢的EPR研究

冯良波, 汪汉卿   

  1. 中国科学院兰州化学物理研究所 OSSO国家重点实验室 兰州 730000
  • 收稿日期:1991-04-12 修回日期:1991-07-29 出版日期:1992-08-20 发布日期:1992-08-20
  • 通讯作者: 冯良波

EPR STUDIES OF THE PHOTOCATALYTIC DEHYDROGE-NATION FOR AQUEOUS ETHANOL SOLUTIONS

FENG LIANG-BO, WANG HAN-QING   

  1. OSSO, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000
  • Received:1991-04-12 Revised:1991-07-29 Online:1992-08-20 Published:1992-08-20

摘要: 本文报道,在含有Pt/CdS的乙醇水溶液中分别加入不同俘获剂: POBN (α-(4-pyridyl N-oxide)-N-tert-butyl nitrone), MV2+(methylviologen), NB(nitrosobenzene)或 TCNQ(7,7,8,8-tetracyano-p-quinodimethane),在可见光(λ≥450nm)照射下,光催化产氢及其光催化脱氢机理的EPR(电子顺磁共振)研究。结果表明,在Pt/CdS-CH3CH2OH/H2O体系中进行可见光反应3小时,其产氢量相当高(0.0136 mmol);在加入POBN的体系中,由于其俘获了CH3HOH自由基而使产氢量降低了三分之二,这说明由CH3HOH经H+产氢比水分解经H+产氢更容易。在加入TCNQ或NB的体系中,由于其俘获了电子(e-)或自由基,因而都未检测到氢气;这说明在可见光照射下,Pt/CdS催化乙醇水溶液脱氢的机理是经由: H++e-→Ñ→1/2H2.

关键词: 可见光, 光催化脱氢, Pt/CdS, 自旋俘获, 电子顺磁共振

Abstract: By employing different spin trapping agents: POBN (α-(4-pyridyl-N-oxide)-N-tert-butyl nitrone), MV2+ (methylviologen), TCNQ (7, 7, 8, 8-tetracyano-p-qui-nodimethane) and NB (nitrosobenzene), EPR spectroscopy was used to probe the photocatalytic dehydrogenation pathway of aqueous ethanol solution suspended by Pt/CdS powder under the irradiation of visible light (λ≥450nm). The results indicated that the amount of hydrogen produced from the system of Pt/CdS-CH3CH2OH/H2O was relatively high (0.0136 mmol) upon irradiation for 3 hours. However adding in POBN to this system resulted in the decreasing of the amount of hydrogen to 2/3 of the value, suggesting that the CH3CHOH was trapped and it was easier to produce hydrogen via H+ decomposed from CH3CHOH than from water. For the system adding TCNQ or NB, no hydrogen has been detected, probably due to the trapping of electron or H radical, and indicating that the dehydrogenation mechanism of aqueous ethanol solution catalyst upon irradiation was vis: H++e-→Ñ→1/2H2.

Key words: Visible light, photocatalytic dehydrogenation, spin trapping, Pt/CdS, EPR