Overcoming the limitations of gold catalysts in hydrogenation: enhanced activity with full hydrogen utilization
Overcoming the limitations of gold catalysts in hydrogenation: enhanced activity with full hydrogen utilization
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DOI：
10.1007/s11144-018-1417-x
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发表时间：
2018-05
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影响因子：
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通讯作者：
M. Keane;Maoshuai Li;Laura Collado;F. Cárdenas-Lizana
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文献类型：
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作者：
M. Keane;Maoshuai Li;Laura Collado;F. Cárdenas-Lizana
纳米级负载金在催化氢化中的应用提供了高化学选择性，但使用远超过化学计量要求的（加压）H2 时活性较低。我们以Au/CeO2（平均Au尺寸 = 2.8 nm）作为测试催化剂，通过一系列方法解决了反应速率低和氢气利用率低的问题。增加的溢出氢（使用 Au/CeO2 与 CeO2 和 SiO2 的物理混合物）和水的促进作用（通过表面氧空位的催化离解）导致糠醛氢化成糠醇的选择性增加四倍。相反，Pd/CeO2和Ni/CeO2促进脱羰（生成呋喃）、氢解（生成2-甲基呋喃）和环还原（生成四氢糠醇）。 Cu/SiO2（平均Cu尺寸 = 7.8 nm）上的（2-丁醇 → 2-丁酮）脱氢与Au/CeO2上的糠醛加氢耦合，进一步提高了脱氢过程中产生的氢气的利用率，进一步提高了速率。该偶联策略允许“无氢”氢化，从而规避了金在标准催化氢化中的限制。这可以开辟新的途径，利用金的超选择性来连续生产高价值商品。
Application of nano-scale supported Au in catalytic hydrogenation delivers high chemoselectivity but low activity using (pressurized) H2far in excess of stoichiometric requirements. We have tackled the issues of low reaction rate and inefficient hydrogen utilization through a series of approaches taking Au/CeO2(mean Au size = 2.8 nm) as a test catalyst. Increased spillover hydrogen (using physical mixtures of Au/CeO2with CeO2and SiO2) and the promotional effect of water (via catalytic dissociation on surface oxygen vacancies) resulted in a fourfold increase in the selective rate of furfural hydrogenation to furfuryl alcohol. In contrast, Pd/CeO2and Ni/CeO2promoted decarbonylation (to furan), hydrogenolysis (to 2-methylfuran) and ring reduction (to tetrahydrofurfuryl alcohol). Coupling (2-butanol → 2-butanone) dehydrogenation over Cu/SiO2(mean Cu size = 7.8 nm) with furfural hydrogenation over Au/CeO2further increased rate with full utilization of the hydrogen generated in dehydrogenation. The coupling strategy allows “hydrogen free” hydrogenation that circumvents the limitation of Au in standard catalytic hydrogenation. This can open new avenues to exploit the ultra-selectivity of Au for continuous production of high value commodity products.