Catalytic performance of Ni/CeO2 catalysts prepared from different routes for CO2 methanation
Catalytic performance of Ni/CeO2 catalysts prepared from different routes for CO2 methanation
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DOI：
10.1016/j.jtice.2021.04.008
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发表时间：
2021-05-05
影响因子：
5.7
通讯作者：
Charinpanitkul, Tawatchai
中科院分区：
文献类型：
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作者：
Ratchahat, Sakhon;Surathitimethakul, Sethanat;Charinpanitkul, Tawatchai
在本研究中，采用微波（MW）、水热（HM）和蒸发（EP）等不同加热方法处理NaOH溶液，通过一步共沉淀法制备了Ni/CeO 2催化剂。通过TEM观察，共沉淀提供了含有d-间距为3.15-3.24埃的（111）平面结构的高度结晶的CeO 2的催化剂。所得CeO 2纳米粒子呈假球形，粒径范围为10.8-12.1 nm。HR-TEM分析的基础上，NiO纳米粒子的大尺寸范围为48.8-51.2 nm被发现纳入CeO 2纳米结构。通过N2吸附测试，所有Ni/CeO 2催化剂均具有介孔特征，比表面积范围为70.5-75.7 m2/g，平均孔径为30 nm。XRD结果表明，H2还原可使NiO物种完全转化为Ni-0物种。XPS分析进一步证实了在852.6eV的能带隙处具有显著峰的Ni-0物质的存在。氢程序升温还原（H-2-TPR）证实NiO物质的α和β峰在低于500 ℃的温度下完全还原。H2-消耗结果表明，MW法制备的Ni/CeO 2催化剂具有较高的金属-载体相互作用（SMSI）。采用MW、HM、EP法制备的Ni/CeO 2催化剂具有CO2甲烷化活性，TOF分别为13.6、10.8和5.8 s（-1），这与Ni晶粒尺寸分别为42.2、50.5和52.8 nm相关。所有制备的Ni/CeO 2催化剂表现出稳定的催化性能，在CO2转化率和CH 4选择性在72 h-时间-运行测试可以忽略不计的下降。相比之下，微波法在自生压力下快速均匀加热制备的Ni/CeO 2催化剂，由于Ni的分散度较高，具有较好的上级催化活性。(C)2021年台湾化学工程师学会。Elsevier B. V.出版，保留所有权利。
In thid study, Ni/CeO2 catalysts were prepared by a one-step co-precipitation of nickel and cerium salts in a NaOH solution treated by different heating methods including microwave (MW), hydrothermal (HM) and evaporation (EP). With TEM observation, the co-precipitation provided the catalysts containing a highly crystalline CeO2 of a (111) plane structure with d-spacing of 3.15-3.24 angstrom. The obtained CeO2 nanoparticles exhibited a pseudo-spherical shape with a size range of 10.8-12.1 nm. Based on HR-TEM analyses, NiO nanoparticles with a large size range of 48.8-51.2 nm were found to be incorporated within the CeO2 nanostructure. By N-2 sorption measurement, all Ni/CeO2 catalysts possessed a mesoporous characteristic with a specific surface area range of 70.5-75.7 m(2)/g and an average pore diameter of 30 nm. XRD results revealed that NiO species could be completely transformed into Ni-0 species by the H-2 reduction process. XPS analyses further confirmed the presence of Ni-0 species with a prominent peak at an energy bandgap of 852.6 eV. Hydrogen temperature-programmed reduction (H-2-TPR) confirmed that alpha and beta peaks of NiO species were completely reduced at a temperature lower than 500 degrees C. The Ni/CeO2 catalyst prepared by MW method exhibited a higher strong metal-support interaction (SMSI) between Ni and CeO2 revealed by H-2 consumption results. The Ni/CeO2 catalysts prepared by MW, HM, EP methods exhibited the CO2 methanation activity with TOF of 13.6, 10.8 and 5.8 s(-1), which could be correlated with the Ni crystallite sizes of 42.2, 50.5 and 52.8 nm, respectively. All prepared Ni/CeO2 catalysts exhibited the stable catalytic performances with a negligible drop in CO2 conversion and CH4 selectivity over 72 h-time-on-stream test. In comparison, the MW method with a rapid and uniform heating under autogenous pressure could result in the Ni/CeO2 catalyst with the superior catalytic activities due to the higher dispersion of Ni. (C) 2021 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.