化学学报 ›› 1996, Vol. 54 ›› Issue (7): 661-666. 上一篇    下一篇

研究论文

RhCo双金属催化剂的研究 Ⅱ. Rh+Co/Al2O3上CO吸附态的动态行为与CO歧化

陈耀强;龚茂初;曹昭;周建略;陈豫;辛勤;张慧;郭燮贤   

  1. 四川大学化学系;中国科学院大连化学物理研究所
  • 发布日期:1996-07-15

Study of RhCo bimetal catalyst Ⅱ. Dynamic behavior of the chemisorbed CO and CO disproportionation on Rh+Co/Al2O3

CHEN YAOQIANG;GONG MAOCHU;CAO ZHAO;ZHOU JIANLUE;CHEN YU;XIN QIN;ZHANG HUI;GUO XIEXIAN   

  • Published:1996-07-15

利用CO与NO作为双探针分子和TP-IR动态方法研究了Rh+Co/Al2O3催化剂上的吸附中心类型, CO吸附态的动态行为以及CO歧化反应。结果表明在Rh+Co/Al2O3上存在大量的孪生CO吸附中心和少量的线式CO吸附中心以及Co上的NO吸附中心。在TPD(真空中)动态过程中, 孪生CO谱带强度逐渐减弱并在325℃完全脱除。明显低于Rh4/Al2O3上孪生CO谱带的脱附温度, 表明Co的加入减弱了孪生中心对CO的吸附强度。在TP(CO中)动态过程中, 吸附的CO谱带上250℃以上才发生强度减小直至消失的行为表明CO歧化在250℃以上才发生。并且孪生中心上的歧化速率高于线式中心。

关键词: 钴, 金属催化剂, 氧化铝, 一氧化碳, 吸附, 铑, 一氧化氮

The forms of adsorption sites, dynamic behavior of chemisorbed CO and CO disproportionation have been investigated by using CO and NO as double probes and TP-IR dynamic method. The results indicate that there are a large amount of adsorption sites for gem-dicarbonyl CO and a very small amount of adsorption sites for linear CO on Rh, and CO sites for adsorbed NO over Rh+Co/Al2O3. The bands of gem-dicarbonyl CO gradually decreased in intensity and fully desorbed at 300℃ during TPD (in vacuum) dynamic process. The temperature fully desorbed for gem-dicarbonyl CO on Rh+Co/Al2O3 is lower than that for gem-dicarbonyl CO on Rh4/Al2O3 indicating that addition of Co weaken CO adsorption strength on Rh^I sites over Rh+Co/Al2O3. The results obtained from TP (in CO) dynamic process indicate that CO disproportionation take place above 250℃ and the rate of CO disproportionation on Rh^I sites is higher than that on linear sites CO over Rh+Co/Al2O3.

Key words: COBALT, METAL CATALYST, ALUMINIUM OXIDE, CARBON MONOXIDE, ADSORPTION, RHODIUM, NITROGEN MONOXIDE

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