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首页> 外文期刊>Catalysis science & technology >The oxidizing pretreatment-mediated autoreduction behaviour of cobalt nanoparticles supported on ordered mesoporous carbon for Fischer-Tropsch synthesis
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The oxidizing pretreatment-mediated autoreduction behaviour of cobalt nanoparticles supported on ordered mesoporous carbon for Fischer-Tropsch synthesis

机译：氧化预处理介导的钴纳米颗粒的自动介导行为在有序的介孔碳中用于Fischer-Tropsch合成

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摘要

Ordered mesoporous carbons (OMCs) were employed to support cobalt species for insight into the autoreduction behaviour of cobalt oxide on carbon substrates and their catalytic performance during the Fischer-Tropsch synthesis (FTS). The as-synthesized samples were subjected to the characterization of N2-physisorption, XPS, in situ XRD, TPR, TG-MS, HAADF-STEM and H2-chemisorption. The results show that the oxidizing pretreatment of OMC substantially improves the dispersion of cobalt species. Consequently, more uniform cobalt particles are observed on the pretreated supports in comparison with their counterparts on pristine OMCs, which enables the autoreduction of cobalt oxide on the carbon supports to occur at a lower temperature owing to the weak metal-support interaction. As compared to the hydrogen-reduced samples, the morphology of cobalt particles suffers from a significant change after the autoreduction and a rnechanism with respect to the anti-oriented diffusion of oxygen atoms is proposed to account for the formation of ellipsoidal or quasi-ellipsoidal particles. During the evaluation of FTS, the autoreduced catalysts exhibit higher activity than the hydrogen-reduced ones owing to more cobalt atoms being exposed on the surface. Dictated by the decreasing cobalt particles, the cobalt-specific activity of pretreated samples is ca. 2.2 times higher than its analog on the pristine OMCs under optimum conditions without any influence on the TOF or at the expense of the C_(5+) hydrocarbon selectivity.
机译：使用有序的介孔碳（OMC）来支持钴物种，以深入了解氧化钴在碳底物上的自动行为及其在Fischer-Tropsch合成期间的催化性能。对ASSSYNTHES的样品进行了N2-骨分析的表征，XPS，原位XRD，TPR，TG-MS，HAADF-STEM和H2-溶剂吸附。结果表明，OMC的氧化预处理大大改善了钴物种的分散体。因此，与原始OMC上的对应物相比，在预处理的支撑物上观察到了更多均匀的钴颗粒，这使碳载体上的氧化钴可以自动在较低的温度下在较低的温度下发生，这是由于弱金属支持的相互作用。与氢还原样品相比，钴颗粒的形态在自动化后发生了显着变化，并且提出了相对于抗氧原子的抗导向扩散的机能，以说明形成椭圆形或Quasi ellipsoidal颗粒的形成。在评估FTS期间，自动催化剂比氢还原的催化剂表现出更高的活性，这是由于表面暴露更多的钴原子。根据钴颗粒的减少决定，预处理样品的钴特异性活性是大约。在最佳条件下，原始OMC上的类似物高2.2倍，而不会影响TOF或以C_（5+）烃选择性影响。

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