Hernández Mejía Carlos, van der Hoeven Jessi E S, de Jongh Petra E, de Jong Krijn P
Inorganic Chemistry and Catalysis, Debye Institute for Nanomaterials Science, Utrecht University, Universiteitsweg 99, 3584 CG Utrecht, The Netherlands.
Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
ACS Catal. 2020 Jul 2;10(13):7343-7354. doi: 10.1021/acscatal.0c00777. Epub 2020 Jun 9.
Efficient and more sustainable production of transportation fuels is key to fulfill the ever-increasing global demand. In order to achieve this, progress in the development of highly active and selective catalysts is fundamental. The combination of bimetallic nanoparticles and reactive support materials offers unique and complex interactions that can be exploited for improved catalyst performance. Here, we report on cobalt-nickel nanoparticles on reducible metal oxides as support material for enhanced performance in the Fischer-Tropsch synthesis. For this, different cobalt to nickel ratios (Ni/(Ni + Co): 0.0, 0.25, 0.50, 0.75, or 1.0 atom/atom) supported on reducible (TiO and NbO) or nonreducible (α-AlO) oxides were studied. At 1 bar, Co-Ni nanoparticles supported on TiO and NbO showed stable catalytic performance, high activities and remarkably high selectivities for long-chain hydrocarbons (C, ∼80 wt %). In contrast, catalysts supported on α-AlO independently of the metal composition showed lower activities, high methane production, and considerable deactivation throughout the experiment. At 20 bar, the combination of cobalt and nickel supported on reducible oxides allowed for 25-50% cobalt substitution by nickel with increased Fischer-Tropsch activity and without sacrificing much C selectivity. STEM-EDX and IR of adsorbed CO pointed to a cobalt enrichment of the nanoparticle's surface and a weaker adsorption of CO in Co-Ni supported on TiO and NbO and not on α-AlO, modifying the rate-determining step and the catalytic performance. Overall, we show the strong effect and potential of reducible metal oxides as support materials for bimetallic nanoparticles for enhanced catalytic performance.
高效且更可持续地生产运输燃料是满足不断增长的全球需求的关键。为了实现这一目标，开发高活性和高选择性催化剂的进展至关重要。双金属纳米颗粒与活性载体材料的结合提供了独特而复杂的相互作用，可用于提高催化剂性能。在此，我们报道了负载在可还原金属氧化物上的钴 - 镍纳米颗粒作为费托合成中提高性能的载体材料。为此，研究了负载在可还原（TiO 和 NbO）或不可还原（α - Al2O3）氧化物上的不同钴镍比（Ni/(Ni + Co)：0.0、0.25、0.50、0.75 或 1.0 原子/原子）。在 1 巴下，负载在 TiO 和 NbO 上的 Co - Ni 纳米颗粒表现出稳定的催化性能、高活性以及对长链烃（C，约 80 wt%）的极高选择性。相比之下，负载在 α - Al2O3 上的催化剂，无论金属组成如何，活性较低，甲烷产量高，并且在整个实验过程中显著失活。在 20 巴下，负载在可还原氧化物上的钴和镍的组合允许用镍替代 25 - 50%的钴，同时提高费托活性且不牺牲太多 C 选择性。STEM - EDX 和吸附 CO 的红外光谱表明，负载在 TiO 和 NbO 而非 α - Al2O3 上的 Co - Ni 纳米颗粒表面钴富集，CO 吸附较弱，这改变了速率决定步骤和催化性能。总体而言，我们展示了可还原金属氧化物作为双金属纳米颗粒载体材料对提高催化性能的强大作用和潜力。
