School of Chemistry and Chemical Engineering, State Key Laboratory of Pulp and Paper Engineering , South China University of Technology , Guangzhou 510640 , P. R. China.
National Engineering Research Center of Chemical Fertilizer Catalyst , Fuzhou University , Fuzhou 350002 , P. R. China.
ACS Appl Mater Interfaces. 2018 Jul 11;10(27):23112-23121. doi: 10.1021/acsami.8b05273. Epub 2018 Jun 27.
Direct dehydrogenation of isobutane to isobutene has drawn extensive attention for synthesizing various chemicals. The Mo-based catalysts hold promise as an alternative to the toxic CrO - and scarce Pt-based catalysts. However, the low activity and rapid deactivation of the Mo-based catalysts greatly hinder their practical applications. Herein, we demonstrate a feasible approach toward the development of efficient and non-noble metal dehydrogenation catalysts based on Mo-C hybrid nanowires calcined at different temperatures. In particular, the optimal Mo-C catalyst exhibits isobutane consumption rate of 3.9 mmol g h and isobutene selectivity of 73% with production rate of 2.8 mmol g h. The catalyst maintained 90% of its initial activity after 50 h of reaction. Extensive characterizations reveal that such prominent performance is well correlated with the adsorption abilities of isobutane and isobutene and the formation of η-MoC species. In contrast, the generation of β-MoC crystalline phase during long-term reaction causes minor decline in activity. Compared to MoO and β-MoC, η-MoC plays a role more likely in suppressing the cracking reaction. This work demonstrates a feasible approach toward the development of efficient and non-noble metal dehydrogenation catalysts.
异丁烷直接脱氢生成异丁烯，因其可用于合成各种化学品而受到广泛关注。与有毒的 CrO3 和稀缺的 Pt 基催化剂相比，Mo 基催化剂作为替代品具有很大的优势。然而，Mo 基催化剂的活性低和快速失活极大地阻碍了其实际应用。在此，我们展示了一种可行的方法，通过在不同温度下煅烧 Mo-C 杂化纳米线来开发高效且非贵金属脱氢催化剂。特别是，最佳的 Mo-C 催化剂在 50 小时的反应后，仍保持 90%的初始活性。广泛的表征揭示了这种优异的性能与异丁烷和异丁烯的吸附能力以及 η-MoC 物种的形成密切相关。相比之下，在长期反应中形成的β-MoC 晶相导致活性略有下降。与 MoO 和 β-MoC 相比，η-MoC 在抑制裂化反应方面发挥了更大的作用。这项工作为开发高效且非贵金属脱氢催化剂提供了一种可行的方法。
