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摘要: 用等体积浸渍法制备了ZrO2-SiO2(ZrSiO)表面复合氧化物负载的Ni-Cu双金属催化剂，并用TPR、XPS、IR、TPD及微反技术考察了稀土La2O3助剂对CH4和H2O在Ni-Cu/ZrSiO催化剂表面上的吸附及甲烷部分氧化制氢反应性能的影响。结果表明，加入La2O3助剂使催化剂表面Ni, Cu原子电子云密度增加，CH4和H2O在催化剂表面上的吸附增强；在反应温度450 ℃、进料摩尔比n-CH4∶nO2∶nH2O＝1∶0-5∶2-5以及甲烷空速SV(CH4)＝1 200 h－1的条件下，催化剂Ni-Cu-La2O3/ZrSiO上CH4转化率大于90％，生成H2的选择性高于99％，副产物CO的选择性仅为1.1％。根据实验结果，讨论了La2O3助催化剂的作用机理。
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关键词:
- 镧助剂 /
- 甲烷部分氧化 /
- 制氢催化剂 /
- Ni-Cu/ZrSiO
Abstract: ZrO2-SiO2 (ZrSiO) supported Ni-Cu-La2O3 catalyst for CH4 partial oxidation to produce hydrogen was prepared by isovolumetric impregnation. By using TPR, XPS, IR, TPD and microreactor techniques, the effect of La2O3 on adsorption and reaction of CH4 with H2O and O2 on the catalyst were studied. The results showed that the addition of La2O3 has obvious influence on the electronic charge distribution of metal active sites Ni, Cu on Ni-Cu/ZrSiO catalyst, and increases the chemisorption intensity of CH4 and H2O. The main reaction products of CH4 partial oxidation with H2O and O2 on Ni-Cu-La2O3/ZrSiO catalyst are H2 and CO2. Under condition of 450 ℃, nCH4∶nO2∶nH2O＝1∶0-5∶2-5 and SV(CH4)=1 200 h－1, conversion of CH4 (xCH4) is greater than 90%, selectivity of H2 (SH2) is more than 99%, and SCO is merely 1.% on Ni-Cu-La2O3/MgSiO catalyst. Moreover, the catalysis mechanism of promoter La2O3 was discussed. -
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