高等学校化学学报

高等学校化学学报 ›› 2005, Vol. 26 ›› Issue (6): 1093.

• 研究论文 • 上一篇    下一篇

Cu/WO3-TiO2光催化剂上丙烯和二氧化碳合成MAA反应性能

梅长松, 钟顺和   

  1. 天津大学化工学院, 天津300072
  • 收稿日期:2004-05-17 出版日期:2005-06-10 发布日期:2005-06-10
  • 通讯作者: 钟顺和(1938年出生),男,教授,博士生导师,从事工业催化设计研究.E-mail:Shzhong@public.tpt.t.jcn E-mail:Shzhong@public.tpt.t.jcn
  • 基金资助:

    国家重大基础研究前期研究专项基金(批准号:2001CCA03600)资助.

Photocatalytic Synthesis of MAA from Propylene and Carbon Dioxide over Cu/WO3-TiO2 Catalyst

MEI Chang-Song, ZHONG Shun-He   

  1. College of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
  • Received:2004-05-17 Online:2005-06-10 Published:2005-06-10

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摘要： 研究了Cu/WO3-TiO2对CO2和C3H6的吸附特性和光催化性能.结果表明,在Cu/WO3-TiO2催化剂表面存在金属位Cu,Lewis酸位W6+和Ti4+以及Lewis碱位W—O—Ti的桥氧和WO的端氧三类活性中心;在金属位Cu和Lewis酸位Ti4+(或W6+)的协同作用下,CO2形成活性较高的卧式吸附态Cu—(CO)—O→Ti4+(或W6+),C3H6的β-H和β-C分别吸附在Lewis碱位WO与金属位Cu上,形成Cu—(CH2)C(CH3)—H→OW吸附态;Cu/WO3-TiO2催化剂吸收阈值蓝移和光吸收量的提高均有利于其催化活性的提高,担载质量分数为10%的WO3光催化剂的催化活性优于其它含量的催化剂,光量子效率最高(19.7%);在383K,0.1MPa,空速200h-1和125W紫外灯辐照下,C3H6转化率为7.4%,甲基丙烯酸(MAA)的选择性超过95%.根据实验结果提出了光促表面催化合成反应的机理.

关键词: 光催化剂, 二氧化碳, 丙烯, 甲基丙烯酸, 反应性能

Abstract: Photocatalytic synthesis of hydrocarbon oxygenates from CO2 with hydrocarbons is of great importance to environmental protection, utilization of carbon resources and synthetic chemistry. Adsorption property of CO2 and C3H6 and photo-stimulated surface reaction to synthesize methacrylic acid from CO2 and C3H6 over the coupled semiconductor WO3-TiO2 catalyst with metallic Cu supported were studied. The experimental results reveal that the three kinds of active sites exist on the surface of Cu/WO3-TiO2 catalyst: Metallic site Cu, Lewis acid sites W6+ and Ti4+, Lewis base sites bridge O in WOTi and terminal O in WO. Chemisorbed CO2 on the surface of Cu/WO3-TiO2 catalyst forms high active horizontal state CuCOO→Ti4+(or W6+) with the synergic action of metallic site Cu and Lewis acid sites Ti4+(or W6+), while dual-sites adsorption of β-H and β-C of C3H6 which forms state CuCH2C(CH3)H→OW, is found mainly on the Lewis base-site WO and the metallic site Cu, respectively. Blue-shifting of band edge of the absorption spectra and increasing of the photo absorption capacity on Cu/WO3-TiO2 catalyst improve the catalysis property of Cu/WO3-TiO2 catalysts. Photo-quantum efficiency of the reaction is the highest among the others, which reaches 19.7%. The selectivity of MAA is over 95% on 1%Cu/10%WO3-TiO2 catalyst under the proper reaction conditions(SV=200 h-1, p=0.1 MPa, T=383 K and P=125 W). Based on the experimental results above, a possible mechanism is proposed for the photo-stimulated surface reaction to synthesize methacrylic acid from CO2 and C3H6 over Cu/WO3-TiO2 catalysts.

Key words: Photocatalyst, Carbon dioxide, Propylene, Methacrylic acid, Reaction performance

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