| 周建略,陈豫,辛梅,左长明,吉晓江,陈红,秦代毅.氧化物担载铑原子簇催化剂的金属载体相互作用的考察——Ⅰ.Rh/V_2O_5和RH/TiO_2催化剂的金属载体强相互作用的比较[J].分子催化,1992,(5): |
| 氧化物担载铑原子簇催化剂的金属载体相互作用的考察——Ⅰ.Rh/V_2O_5和RH/TiO_2催化剂的金属载体强相互作用的比较 |
| Studies on the Metal-Support Interaction for Supported Rhodium Cluster Catalysts on Oxides I Comparison of SMSI for Rh/V2O5 and Rh/TiO2 Catalysts |
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| DOI： |
| 中文关键词: 铑催化剂,铑原子簇合物,金属载体强相互作用 |
| 英文关键词:Rhodium catalyst, Rhodium cluster, Strong metal-support interaction. |
| 基金项目: |
| 周建略 陈豫 辛梅 左长明 吉晓江 陈红 秦代毅 |
| 四川大学分析测试中心，四川大学分析测试中心，四川大学分析测试中心，四川大学分析测试中心，四川大学分析测试中心，四川大学分析测试中心，四川大学分析测试中心 成都 610064，成都 610064，成都 610064，成都 610064，成都 610064，成都 610064，成都 610064 |
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| 中文摘要: |
| 本文用XPS和XRD考察了由Rh_4(CO)_(12)出发制得的Rh/V_2O_5和Rh/TiO_2两种催化剂的金属载体强相互作用的差别。实验结果表明,1)高温H_2还原的Rh/TiO_2催化剂,经氧处理后即能恢复吸H_2能力。Rh/V_2O_5催化剂在较低温度(473K)H_2还原时Rh就进入SMSI状态,吸H_2能力被完全抑制,373K氧处理并不能使之恢复,吸H_2性质表现出不可逆性。2)与Rh/TiO_2催化剂的TiO_2相比,Rt/V_2O_5催化剂的V_2O_5更易还原,Rh对V_2O_5的还原有明显的促进作用。3)担载在TiO_2上的Rh比在V_2O_5上更易还原。4)还原后,催化剂表层的Rh/V、RH/Ti均有较大幅度的降低。用氧空位模型能较好地说明Rh/TiO_2催化剂的实验结果,而Rh/V_2O_5催化剂的实验结果适于用钒氧化物覆盖模型解释。 |
| 英文摘要: |
| The differences in the manifestation of strong metal-support interaction (SMSI) for Rh/V2O5and Rh/TiO2 catalysts were studied by O2 - H2 titration, XPS and XRD. Cluster Rh4(CO)12 was synthesized according to reference(8). The catalysts were prepared by impregnation of the pretreated oxides (V2O5and TiO2) with Rh4 (CO)12 solution. The Rh content of the catalysts was 1 wt%. The samples were decarbonylated by evacuation for 2 h at 473 K, and then reduced in flowing H2 for 2 h at 473. 673 and 873 K respectively. O2-H2 titration, XPS and XRD determination were carried out for the reduced samples.The results show: 1) 373 K oxygen treatment can restore H2 sorption capacity of the high-temperature (873 K) reduced Rh/TiO2 catalyst. For Rh/V2O5 catalyst, after lower-temperature(473 K) reduction, the H2 sorptive property is completely suppressed, Rh is in full SMSI state. The sorptive property can not be restored by 373 K oxygen treatment, and exhibits irreversibility. 2) V2O5 of Rh/ V2O5 catalyst is easier to be reduced than TiO2 of Rh/TiO2, Rh can greatly promote the reduction of V2O5. 3) Rh supported on V2O5 is more difficultly reduced than that on TiO2. 4) Rh/V and Rh/Ti ratios of the surface of the catalysts decreased remarkably after the reduction.The experimental results of Rh/TiO2 and Rh/V2O5 catalysts can be explained by oxygen vacancy model and complete coverage by vanadium oxide overlayer, respectively. |
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