Synthesis of atomically dispersed catalysts with high metal loading and thermal stability is challenging but particularly valuable for industrial application in heterogeneous catalysis. Here, we report a facile synthesis of a thermally stable atomically dispersed Ir/α-MoC catalyst with metal loading as high as 4 wt%, an unusually high value for carbide supported metal catalysts. The strong interaction between Ir and the α-MoC substrate enables high dispersion of Ir on the α-MoC surface, and modulates the electronic structure of the supported Ir species. Using quinoline hydrogenation as a model reaction, we demonstrate that this atomically dispersed Ir/α-MoC catalyst exhibits remarkable reactivity, selectivity and stability, for which the presence of high-density isolated Ir atoms is the key to achieving high metal-normalized activity and mass-specific activity. We also show that the water-promoted quinoline hydrogenation mechanism is preferred over the Ir/α-MoC, and contributes to high selectivity towards 1,2,3,4-tetrahydroquinoline. The present work demonstrates a new strategy in constructing a high-loading atomically dispersed catalyst for the hydrogenation reaction.

中文翻译：

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具有高金属负载量和热稳定性的原子分散 Ir/α-MoC 催化剂用于水促进加氢反应

具有高金属负载和热稳定性的原子分散催化剂的合成具有挑战性，但对于多相催化的工业应用特别有价值。在这里，我们报告了一种热稳定的原子分散的 Ir/α-MoC 催化剂的简便合成，其金属负载量高达 4 wt%，这对于碳化物负载的金属催化剂来说价值异常高。Ir 和 α-MoC 衬底之间的强相互作用使 Ir 在 α-MoC 表面上的高度分散，并调节了负载的 Ir 物质的电子结构。使用喹啉加氢作为模型反应，我们证明了这种原子分散的 Ir/α-MoC 催化剂表现出显着的反应性、选择性和稳定性，其中，高密度孤立 Ir 原子的存在是实现高金属归一化活性和质量比活性的关键。我们还表明，水促进的喹啉氢化机理优于 Ir/α-MoC，并有助于对 1,2,3,4-四氢喹啉具有高选择性。目前的工作展示了一种构建用于加氢反应的高负载原子分散催化剂的新策略。