image: (a) SEM image of Rh1/Cs-PTA; (b) Tertiary structure: porous particle (100~200 nm); (c) Secondary structure: ionic crystals (10~20 nm); (d) Primary structure: top view of the optimized geometry of Rh1/PTA, ~1 nm), purple: Rh, blue: W, red: O, pink: P; (e) Charge density difference of Rh1/PTA; (f) Spin-polarized partial density of states projected on Rh s, p and d (green, blue and red) states. view more
Credit: ©Science China Press
This study is led by Yan Ning (Joint School of National University of Singapore and Tianjin University; Department of Chemical & Biomolecular Engineering, National University of Singapore) and Professor Yu Qi (Shaanxi University of Technology). A porous POM salt-supported Rh single-atom catalyst was prepared to promote the hydroformylation reaction.
The catalyst had three classes of structures consisting of PTA anions (primary structure), ionic crystals (secondary structure) and assembled spherical porous particles (tertiary structure). The Rh atoms were firmly coordinated onto the PTA surface within the crystals. During styrene hydroformylation, the counter-cation of PTA played a key role in regulating the pore size of the catalysts, which had a substantial influence on the catalytic activity. Rh1/Cs-PTA exhibited the highest activity (TOF = 1076 h-1) compared to Rh1/Rb-PTA and Rh1/K-PTA, while the stereoselectivity was not altered significantly (n-/iso-aldehyde = 1.2).
This study enriches the understanding of the structure and catalytic properties of PTA-supported single-atom materials. The cation-controlled synthesis of catalysts may also be applied to prepare other single-atom catalysts with tunable pore size distributions.
https://www.sciengine.com/NSO/doi/10.1360/nso/20220064
Journal
National Science Open