Balancing free and confined metallic Ni for an active and stable catalyst-A case study of CO methanation over Ni/Ni-Al2O3

• 作者: Chang Liu Han-Qing Ge Min-Li Zhu Xian-Ying Shi Yong-Hong Song Yong-Shan Xiao Zhao-Tie Liu Zhong-Wen Liu
• 来源期刊: 能源化学
• 年，卷（期）: 2020,（11）
• 页码范围: 73-84
• 页数: 12页
• 语种: 英文

摘要

We propose a new strategy to make an active and stable Ni-based catalyst which can be operated in a wide range of reaction temperatures.The ordered mesoporous alumina (OMA) with confined Ni in the pore wall (Ni-OMA) was prepared via the one-pot evaporation induced self-assembly method.By using the incipient impregnation method,different amounts of free Ni were loaded over Ni-OMA (Ni/Ni-OMA) at a fixed total NiO content of 15 wt％.Characterization results confirmed the formation of wellstructured Ni-OMA,and the ordered structure was still well preserved even after impregnating NiO at a content of as high as 12 w～.The catalysts were evaluated for the CO methanation as a model reaction under varied conditions.Importantly,the activity and stability of Ni/Ni-OMA for the tiffed reaction were significantly regulated by simply changing the ratio of the confined to free Ni.Over the optimum catalyst of NiO (2 wt％)/NiO (13 wt％)-OMA,the high activity at a temperature of as low as 300 ℃ was achieved with the space-time yield of methane over 7.6 g gcat-1 h-1 while a long-term stability for a time-on-stream of 400 h was confirmed without an observable deactivation under the conditions of 600 ℃ and an extremely high gas hourly space velocity of 120,000 mL g-1 h-1.The results were well explained as the integrated merits of the free Ni for a high dispersion and the confined Ni in OMA for the anti-sintering property.