Key Laboratory for Colloid and Interface Chemistry, Key Laboratory of Special Aggregated Materials, School of Chemistry and Chemical Engineering, Shandong University, Jinan250100, China.
School of Materials and Environmental Engineering, Chizhou University, Chizhou247000, China.
J Am Chem Soc. 2023 Feb 1;145(4):2252-2263. doi: 10.1021/jacs.2c10326. Epub 2023 Jan 19.
It is highly desirable to fabricate an accessible catalyst surface that can efficiently activate reactants and desorb products to promote the local surface reaction equilibrium in heterogeneous catalysis. Herein, rare-earth oxycarbonates (LnOCO, where Ln = La and Sm), which have molecular-exchangeable (HO and CO) surface structures according to the ordered layered arrangement of LnO and CO ions, are unearthed. On this basis, a series of LnOCO-supported Cu catalysts are prepared through the deposition precipitation method, which provides excellent catalytic activity and stability for the water-gas shift (WGS) reaction. Density functional theory calculations combined with systematic experimental characterizations verify that HO spontaneously dissociates on the surface of LnOCO to form hydroxyl by eliminating the carbonate through the release of CO. This interchange efficiently promotes the WGS reaction equilibrium shift on the local surface and prevents the carbonate accumulation from hindering the active sites. The discovery of the unique layered structure provides a so-called "self-cleaning" active surface for the WGS reaction and opens new perspectives about the application of rare-earth oxycarbonate nanomaterials in C1 chemistry.
制备一种易于接近的催化剂表面，使其能够有效地激活反应物并解吸产物，以促进多相催化中的局部表面反应平衡，这是非常理想的。在此，发现了具有分子可交换（HO 和 CO）表面结构的稀土氧碳酸盐（LnOCO，其中 Ln = La 和 Sm），根据 LnO 和 CO 离子的有序层状排列。在此基础上，通过沉积沉淀法制备了一系列 LnOCO 负载的 Cu 催化剂，该催化剂对水气变换（WGS）反应具有优异的催化活性和稳定性。密度泛函理论计算结合系统的实验表征验证了 HO 通过释放 CO 从碳酸盐中消除，从而在 LnOCO 表面自发解离形成羟基。这种相互交换有效地促进了局部表面上 WGS 反应平衡的转移，并防止碳酸盐的积累阻碍活性位点。这种独特的层状结构的发现为 WGS 反应提供了一种所谓的“自清洁”活性表面，并为稀土氧碳酸盐纳米材料在 C1 化学中的应用开辟了新的视角。
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