In-situ generation and stabilization of gas bubbles for multiphase catalysis.

Abstract

Introducing stable gas bubbles in liquid is important for the industrial synthesis of chemicals and intermediates via multiphase reactions because of limited solubility of gaseous reactants such as H₂ and O₂. Herein, a bubble-stabilized system is constructed via in-situ nucleation of bubbles at the surfaces of various polymer nanofibers that circumvents the repulsive interactions between gas-liquid interfaces and nanofibers. During bubble growth processes, nanofibers are self-assembled and interwoven to build spatial nanofiber network surrounding bubbles, firmly trapping bubbles in the liquid phase. Surprisingly, the immobilization of bubbles in liquid can be sustained up to 20 h. These trapped bubbles can serve as gas storage vessels to remarkably boost the multiphase reactions because of the adequate gas-liquid-solid contact sites as demonstrated by the multiphase nitroarenes reduction in contrast to the bubble-free system. Furthermore, the immobilized bubbles are almost completely utilized (98.9 %) in multiphase reactions. This work provides an enlightenment for capturing and storing bubbles in liquid towards industrial multiphase reactions.