Hollow Carbon Sphere Nanoreactors Loaded with PdCu Nanoparticles: Void‐Confinement Effects in Liquid‐Phase Hydrogenations

• Published in: Angewandte Chemie International Edition Vol. 59; no. 42; pp. 18374 - 18379
• Main Authors: Dong, Chao, Yu, Qun, Ye, Run‐Ping, Su, Panpan, Liu, Jian, Wang, Guang‐Hui
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 12.10.2020; John Wiley and Sons Inc
• Edition: International ed. in English
• Subjects: Carbon; Catalysis; Chemical synthesis; Communication; Communications; Confinement; Deceleration; heterogeneous catalysis; hollow nanoreactors; hydrogenation; Mass transfer; Nanoparticles; shape-selective catalysis; Void space; void-confinement effects; heterogeneous catalysis; void-confinement effects; shape-selective catalysis; hollow nanoreactors; hydrogenation
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202007297

Nanoreactors with hollow structures have attracted great interest in catalysis research due to their void‐confinement effects. However, the challenge in unambiguously unraveling these confinement effects is to decouple them from other factors affecting catalysis. Here, we synthesize a pair of hollow carbon sphere (HCS) nanoreactors with presynthesized PdCu nanoparticles encapsulated inside of HCS (PdCu@HCS) and supported outside of HCS (PdCu/HCS), respectively, while keeping other structural features the same. Based on the two comparative nanoreactors, void‐confinement effects in liquid‐phase hydrogenation are investigated in a two‐chamber reactor. It is found that hydrogenations over PdCu@HCS are shape‐selective catalysis, can be accelerated (accumulation of reactants), decelerated (mass transfer limitation), and even inhibited (molecular‐sieving effect); conversion of the intermediate in the void space can be further promoted. Using this principle, a specific imine is selectively produced. This work provides a proof of concept for fundamental catalytic action of the hollow nanoreactors. A pair of hollow carbon sphere (HCS) nanoreactors with PdCu nanoparticles encapsulated inside the HCS (PdCu@HCS) and supported outside the HCS (PdCu/HCS) have been prepared. Based on the two comparable systems, the void‐confinement effects of hollow nanoreactors in liquid‐phase hydrogenation have been extensively investigated in a two‐chamber reactor.