Sub-Nanometer Ru Clusters on Ceria Nanorods as Efficient Catalysts for Ammonia Synthesis under Mild Conditions

作者：Ji Feng, Lin Liu, Xiaohua Ju, Miaomiao Wang, Xilun Zhang, Jiemin Wang, Ping Chen · 发表于：ACS Sustainable Chemistry & Engineering · 年份：2022 · DOI：10.1021/acssuschemeng.2c01635 · 被引用次数：29 · 研究领域：Ammonia Synthesis and Nitrogen Reduction、Nanocluster Synthesis and Applications、Nanomaterials for catalytic reactions

The wide availability of hydrogen from renewable energy has triggered increasing interest in developing green ammonia synthesis under mild conditions, which relies on the development of efficient catalysts. Here, highly dispersed sub-nanometer Ru clusters on CeO 2 nanorods (Ru clusters/CeO 2 ) which lack B5 sites were successfully synthesized and investigated as catalysts for ammonia synthesis. Structure analysis results reveal that the sub-nanometer Ru clusters on the CeO 2 support have structures much different from that of the Ru nanoparticle counterpart. The Ru clusters/CeO 2 catalyst exhibits higher activity than the Ru nanoparticle counterpart on CeO 2, even outperforming many typical benchmark Ru-based ammonia synthesis catalysts. Moreover, a highly stable performance was achieved over the Ru clusters/CeO 2 catalyst in a relatively long period of over 200 h. Kinetic analysis, H–D exchange, and nitrogen isotopic exchange results reveal that the sub-nanometer Ru cluster species can facilitate the activation and dissociation of hydrogen and nitrogen molecules, mainly responsible for its superior activity and intrinsic activity in ammonia synthesis. This work offers insight into the new kind of active site of Ru-based catalysts for ammonia synthesis, which may help to guide the design of efficient Ru cluster catalysts for ammonia synthesis under mild conditions.