Tsiotsias Anastasios I, Charisiou Nikolaos D, Dabbawala Aasif A, Hussien Aseel G S, Sebastian Victor, Hinder Steven J, Baker Mark A, Mao Samuel, Polychronopoulou Kyriaki, Goula Maria A
Laboratory of Alternative Fuels and Environmental Catalysis (LAFEC), Department of Chemical Engineering, University of Western Macedonia, 50100 Kozani, Greece.
Department of Mechanical Engineering, Khalifa University of Science and Technology, Abu Dhabi P.O. Box 127788, United Arab Emirates.
Nanomaterials (Basel). 2025 Jul 1;15(13):1022. doi: 10.3390/nano15131022.
The synthesis method of the Pr-doped CeO catalyst support in Ni/Pr-CeO CO methanation catalysts is varied by changing the type/basicity of the precipitating solution and the hydrothermal treatment temperature. The use of highly basic NaOH as the precipitating agent and elevated hydrothermal treatment temperature (100 or 180 °C) leads to the formation of structured Pr-doped CeO nanorods and nanocubes, respectively, whereas the use of a mildly basic NH-based buffer in the absence of hydrothermal treatment (i.e., co-precipitation) leads to an unstructured mesoporous morphology with medium-sized supported Ni nanoparticles. The latter catalyst (Ni/CP_NH3) displays a high surface area, high population of moderately strong basic sites, high oxygen vacancy population, and favorable Ni dispersion. These properties lead to a higher catalytic activity for CO methanation (75% CO conversion and 99% CH selectivity at 350 °C) compared to the catalysts with structured nanorod and nanocube support morphologies, which are found to contain a significant amount of leftover Na from the synthesis procedure that can act as a catalyst inhibitor. In addition, the best-performing Ni/CP_NH3 catalyst is shown to be highly stable, with minimal deactivation during time-on-stream operation.
通过改变沉淀溶液的类型/碱度以及水热处理温度，可改变Ni/Pr-CeO CO甲烷化催化剂中Pr掺杂CeO催化剂载体的合成方法。使用高碱性的NaOH作为沉淀剂并提高水热处理温度（100或180°C），分别导致形成结构化的Pr掺杂CeO纳米棒和纳米立方体，而在没有水热处理（即共沉淀）的情况下使用弱碱性的基于NH的缓冲剂会导致形成具有中等尺寸负载型Ni纳米颗粒的非结构化介孔形态。后一种催化剂（Ni/CP_NH3）具有高表面积、大量中等强度的碱性位点、高氧空位数量以及良好的Ni分散性。与具有结构化纳米棒和纳米立方体载体形态的催化剂相比，这些特性导致其对CO甲烷化具有更高的催化活性（在350°C时CO转化率为75%，CH选择性为99%），后者在合成过程中含有大量可作为催化剂抑制剂的残留Na。此外，性能最佳的Ni/CP_NH3催化剂显示出高度稳定性，在连续运行期间失活最小。
