Hydrogen spillover in the Fischer-Tropsch synthesis: An analysis of gold as a promoter for cobalt-alumina catalysts
Hydrogen spillover in the Fischer-Tropsch synthesis: An analysis of gold as a promoter for cobalt-alumina catalysts
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DOI：
10.1016/j.cattod.2015.12.019
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发表时间：
2016-10-15
期刊：
影响因子：
5.3
通讯作者：
van Steen, Eric
中科院分区：
文献类型：
--
作者：
Nabaho, Doreen;Niemantsverdriet, J. W. (Hans);van Steen, Eric
本研究研究了金作为 Co/Al2O3 费托催化剂中铂助催化剂的潜在替代品的操作情况。 Au-Co/Al2O3 与模型混合 Au-Co 样品（由 Au/Al2O3 + Co/Al2O3 的机械混合物组成）一起进行测试，以研究氢溢出，这已被证明在还原促进机制中发挥着至关重要的作用。 TPR、TGA 和原位 XRD 提供了支持 Au-Co/Al2O3 中负载氧化钴微晶还原性提高的证据。然而，与之前对贵金属还原促进剂的研究相比，没有观察到混合金钴催化剂的还原性有所改善。据推测，即使在 Au-Co/Al2O3 还原过程中发生金钴溢出，金和钴微晶之间的巨大分离，加上金对氢活化的亲和力低得多，对混合样品中溢出过程的效率产生了不利影响。尽管如此，Au-Co/Al2O3 具有改进的基于质量的活性，并且转换频率与铂促进的样品相当，这凸显了金作为 Co/Al2O3 催化剂的还原促进剂的潜力。 (C) 2015 Elsevier B.V. 保留所有权利。
This study investigated the operation of gold as a potential substitute for the platinum promoter in the Co/Al2O3 Fischer-Tropsch catalyst. Au-Co/Al2O3 was tested in conjunction with a model Hybrid Au-Co sample (comprised of a mechanical mixture of Au/Al2O3 + Co/Al2O3) to investigate hydrogen spillover which has been demonstrated to play a vital role in the reduction promotion mechanism. TPR, TGA and in situ XRD provided evidence to support the improved reducibility of supported cobalt oxide crystallites in Au-Co/Al2O3. However, no improvement in the reducibility of the Hybrid Au-Co catalyst was observed, in contrast to previous studies on noble metal reduction promoters. It was hypothesized that even though gold-to-cobalt spillover occurred during reduction in Au-Co/Al2O3, the great separation between the gold and cobalt crystallites, combined with gold's much lower affinity for hydrogen activation adversely affected the efficiency of the spillover process in the hybrid sample. Nevertheless, Au-Co/Al2O3 had an improved mass-based activity, and a turnover frequency comparable to a platinum promoted sample, which highlighted the potential of gold as a reduction promoter for Co/Al2O3 catalysts. (C) 2015 Elsevier B.V. All rights reserved.