Addressing the quantitative conversion bottleneck in single-atom catalysis
Zhongxin Chen, Jingting Song, Rongrong Zhang, Runlai Li, Qikun Hu, Pingping Wei, Shibo Xi, Xin Zhou, Phuc T.T. Nguyen, Hai M. Duong, Poh Seng Lee, Xiaoxu Zhao, Ming Joo Koh, Ning Yan, Kian Ping Loh
Abstract
Abstract Single-atom catalysts (SACs) offer many advantages, such as atom economy and high chemoselectivity; however, their practical application in liquid-phase heterogeneous catalysis is hampered by the productivity bottleneck as well as catalyst leaching. Flow chemistry is a well-established method to increase the conversion rate of catalytic processes, however, SAC-catalysed flow chemistry in packed-bed type flow reactor is disadvantaged by low turnover number and poor stability. In this study, we demonstrate the use of fuel cell-type flow stacks enabled exceptionally high quantitative conversion in single atom-catalyzed reactions, as exemplified by the use of Pt SAC-on-MoS 2 /graphite felt catalysts incorporated in flow cell. A turnover frequency of approximately 8000 h −1 that corresponds to an aniline productivity of 5.8 g h −1 is achieved with a bench-top flow module (nominal reservoir volume of 1 cm 3 ), with a Pt 1 -MoS 2 catalyst loading of 1.5 g (3.2 mg of Pt). X-ray absorption fine structure spectroscopy combined with density functional theory calculations provide insights into stability and reactivity of single atom Pt supported in a pyramidal fashion on MoS 2 . Our study highlights the quantitative conversion bottleneck in SAC-mediated fine chemicals production can be overcome using flow chemistry.