Enhanced catalytic performances of Ni/Al2O3 catalyst via addition of V2O3 for CO methanation
Enhanced catalytic performances of Ni/Al2O3 catalyst via addition of V2O3 for CO methanation
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DOI：
10.1016/j.apcata.2014.09.028
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发表时间：
2014-11-01
影响因子：
5.5
通讯作者：
Su, Fabing
中科院分区：
文献类型：
--
作者：
Liu, Qing;Gu, Fangna;Su, Fabing
采用共浸渍法制备了高活性、抗焦化的Ni-V2O3/Al2O3催化剂，用于CO和CO2甲烷化。研究了钒的加入对催化剂结构、镍的分布和还原性、形貌和表面特性的影响。与无钒催化剂相比，Ni-V2O3/Al2O3催化剂在CO甲烷化反应中的活性、热稳定性和抗结焦性能均有显著提高。此外，这些催化剂在常压和2.0 MPa压力下均表现出较高的CO2甲烷化活性。结果表明，Ni- v2o3 /Al2O3催化剂在煅烧过程中生成Ni3V2O8，与未添加钒的情况相比，Ni3V2O8形成的Ni颗粒尺寸更小（约3.0 nm）。Ni- v2o3 /Al2O3催化剂对CO甲烷化反应具有较高的催化活性，主要是由于H-2吸附量较大、Ni分散程度较高以及金属Ni纳米颗粒较小。V2O3的氧化还原循环增加了氧空位，促进了CO2副产物的解离，生成了表面氧中间体，从而防止了CO甲烷化过程中Ni颗粒上的碳沉积。(C) 2014 Elsevier B.V.版权所有
Highly active and coking resistant Ni-V2O3/Al2O3 catalysts were prepared by co-impregnation method for CO and CO2 methanation. The influence of vanadium oxide addition on catalyst structure, distribution and reducibility of Ni species, morphology and surface characteristics, was investigated in detail. Compared to the catalyst without vanadium, the Ni-V2O3/Al2O3 catalysts showed significant improvement in the activity, thermal stability, and resistance to coke formation in CO methanation. In addition, these catalysts also showed high activities for CO2 methanation at both atmospheric and 2.0 MPa pressures. It was found that Ni3V2O8 was formed during the calcination of the Ni-V2O3/Al2O3 catalysts, which led to the formation of smaller Ni particle sizes (ca. 3.0 nm) as compared to the case without vanadium oxide addition. The higher catalytic activity over the Ni-V2O3/Al2O3 catalysts for CO methanation was mainly due to the larger H-2 uptake, the higher Ni dispersion as well as the smaller metallic Ni nanoparticles. The oxidation-reduction cycle of V2O3 could increase the oxygen vacancies, which enhanced the dissociation of CO2 by-product and generated surface oxygen intermediates, thus preventing carbon deposition on the Ni particles in CO methanation. (C) 2014 Elsevier B.V. All rights reserved.