催化学报

催化学报 ›› 2007, Vol. 28 ›› Issue (1): 22-26.

• 研究论文 • 上一篇    下一篇

不同粒径的Ni/SiO2催化剂上CH4和CO2吸附活化的漫反射傅里叶变换红外光谱研究

郭建忠1,2,侯昭胤1,高静1,郑小明1   

  1. 1 浙江大学催化研究所, 浙江杭州 310028; 2 浙江林学院化学系, 浙江临安 311300
  • 收稿日期:2007-01-25 出版日期:2007-01-25 发布日期:2010-08-28

DRIFTS Study on Adsorption and Activation of CH4 and CO2 on Ni/SiO2 Catalyst with Various Ni Particle Sizes

GUO Jianzhong1,2, HOU Zhaoyin1, GAO Jing1, ZHENG Xiaoming1*   

  1. 1 Institute of Catalysis, Zhejiang University, Hangzhou 310028, Zhejiang, China; 2 Department of Chemistry, Zhejiang Forestry University, Lin’an 311300, Zhejiang, China
  • Received:2007-01-25 Online:2007-01-25 Published:2010-08-28

PDF

872

被引次数

21

摘要： 采用原位漫反射傅里叶变换红外光谱研究了CH4和CO2在不同粒径的Ni/SiO2催化剂上的吸附及活化. 结果表明,在不同粒径的催化剂上,检测到有CH4解离生成的CHx(x=1～3)物种,以及催化剂表面吸附的CHx物种与表面-OH 作用生成的CHx-O物种. CH4的裂解强烈依赖于催化剂表面Ni颗粒的大小,在粒径8 nm左右的Ni颗粒上, CH4较易解离; CO2难以直接在Ni/SiO2催化剂表面发生解离吸附,但CH4解离生成的吸附H对CO2的解离吸附具有明显的促进作用; CH4与CO2共吸附时,较小粒径的Ni可以促进CO2与表面氧物种发生反应,生成单齿表面碳酸盐物种.

关键词: 甲烷, 二氧化碳, 镍, 二氧化硅, 负载型催化剂, 吸附, 活化, 红外光谱

Abstract: The adsorption and activation of CH4 and CO2 on Ni/SiO2 catalyst with different Ni particle sizes were investigated by diffuse reflectance infrared Fourier transform spectroscopy. CHx species (x=1-3) were observed on the catalyst with different Ni particle sizes when CH4 was adsorbed on its surface. The CH3-O species was also detected as the result of an interaction of CHx species with surface hydroxyl groups. The dissociation of CH4 depended intensively on the Ni particle size. CH4 dissociated more easily on the Ni/SiO2 catalyst with a Ni particle size of approximate 8 nm. CO2 was very difficult to dissociate on the Ni/SiO2 catalyst, while the adsorbed H from CH4 dissociation promoted the dissociation of CO2. Small Ni particles might be helpful to hydrogen overflow to the support for CO2 activation. In co-adsorption of CH4 and CO2, the monodentate carbonate species was observed on the Ni/SiO2 catalyst with smaller Ni particle size, which indicated that smaller Ni particles could promote the reaction of CO2 with surface oxygen species.

Key words: methane, carbon dioxide, nickel, silica, supported catalyst, adsorption, activation, infrared spectroscopy