Effective Ensemble of Pt Single Atoms and Clusters over the (Ni,Co)(OH)2 Substrate Catalyzes Highly Selective, Efficient, and Stable Hydrogenation Reactions

• Published in: ACS catalysis 2022-07, Vol.12 (13), p.8104-8115
• Main Authors: Zhu, Lihua, Sun, Yilun, Zhu, Huaze, Chai, Guoliang, Yang, Zhiqing, Shang, Congxiao, Ye, Hengqiang, Chen, Bing Hui, Kroner, Anna, Guo, Zhengxiao
• Format: Article
• Language: English
• ISSN: 2155-5435; 2155-5435
• DOI: 10.1021/acscatal.2c01901

A Pt–Ni–Co catalyst was synthesized with Pt single atoms and atomic clusters (SAACs) dispersed over (Ni,Co)­(OH)2 nanoparticles on a carbon matrix, which leads to high catalytic activity, up to 100% conversion, and selectivity in the hydrogenation of nitroaromatics under moderate conditions (H2 ∼ 1.0 MPa and ≤40 °C). A synergistically coordinated ensemble effect of the Pt SAACs is identified with the strongly polarized Pt single atoms preferentially adsorbing the −NO2 and the Pt clusters adsorbing and homolytically dissociating H2 molecules, and the H species then readily move to the adsorbed −NO2 group, overcoming a much reduced energy barrier on the (Ni,Co)­(OH)2, enhancing the reaction rate by ca. 50 times. The approach not only reveals the coordinated ensemble catalysis mechanism of SAACs but also provides a strategy of developing highly efficient and selective catalysts by fine tuning of the electronic microenvironment from single atoms to atomic clusters co-located over a multimetallic substrate. The demonstrated case for nitroarenes can be readily applied for other species containing −NO2 or other easily hydrogenated groups (such as CC, CN, and CO).