Effect of MoO3 on Structures and Properties of Ni-SiO2 Methanation Catalysts Prepared by the Hydrothermal Synthesis Method
Effect of MoO3 on Structures and Properties of Ni-SiO2 Methanation Catalysts Prepared by the Hydrothermal Synthesis Method
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DOI：
10.1021/ie401708h
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发表时间：
2013-10
影响因子：
4.2
通讯作者：
Jiaying Zhang;Z. Xin;Xin Meng;Yuhao Lv;M. Tao
中科院分区：
文献类型：
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作者：
Jiaying Zhang;Z. Xin;Xin Meng;Yuhao Lv;M. Tao
采用水热合成法制备了MoO 3摩尔含量为0.5%~ 5.0%的Ni/SiO2催化剂，并在连续流动固定床反应器上考察了其合成天然气（SNG）性能。MoO 3的加入可使Ni-SiO2催化剂的活性显著提高，主要是由于MoO 3向Ni物种的电子转移，而过量的MoO 3（>3.0%）会使活性金属部分被MoO 3覆盖并形成Ni-Mo合金，从而降低催化剂的活性。Ni-0.5%Mo-SiO2催化剂在400 °C、2. 0 MPa、12000 mL/g/h条件下，CO转化率达100%，CH 4产率达99%以上，具有最佳的催化活性。热重分析（TG）和程序升温还原（TPR）结果表明，MoO 3对Ni-SiO2的积碳有抑制作用，过量的MoO 3（>1.0%）会削弱金属镍与载体之间的相互作用。XRD、TPR和TG的结果表明，在催化剂稳定性和热稳定性试验中，催化剂的失活是由于催化剂的烧结而不是积碳。
Several nickel-incorporated SiO2 catalysts with MoO3 molar content in range of 0.5% to 5.0% were prepared by the hydrothermal synthesis method and investigated for synthetic natural gas (SNG) production in a continuous flow fixed-bed reactor. MoO3 can significantly improve the activity of Ni-SiO2 due to electron transfer from MoO3 to Ni species, while excessive MoO3 (>3.0%) will reduce the catalyst activity due to partial coverage of active metal by MoO3 and formation of Ni–Mo alloy. Ni-0.5%Mo-SiO2 achieves the best activity with 100% CO conversion and ∼99% CH4 yield at 400 °C, 2.0 MPa, and 12000 mL/g/h. The results of thermogravimetry (TG) and temperature-programming reduction (TPR) show that MoO3 can inhibit carbon deposition of Ni-SiO2 and excessive MoO3 (>1.0%) will weaken the interaction between metallic nickel and the support. The results of XRD, TPR, and TG show that catalyst sintering rather than carbon deposition leads to catalyst deactivation in catalytic stability and thermal stability tests.