Bio-inspired fabrication of chitosan/PEO/TiCT 2D MXene nanosheets supported palladium composite nanofiber catalysts via electrospinning.

In this study, novel chitosan/polyethylene oxide/TiCT 2D MXene nanosheets (CS/PEO/TiCT) nanofibers were successfully prepared by a continuous electrospinning process. During the electrospinning process, induced by the syringe tip capillary effects and electric field force, the TiCT nanosheets were aligned along the direction of the nanofiber formation to occur a highly oriented structure. This well-ordered arrangement of the inorganic TiCT nanosheets within the organic polymer matrix nanofiber was similar with nacre-like 'brick-and-motar' structure to some extent, resulting in a marked increase in thermal stability and mechanical properties of the resultant CS/PEO/TiCT nanofiber. As 4 wt% of TiCT nanosheets loaded, the highest tensile strength of the CS/PEO/TiCT nanofiber mats was achieved as 31.7 MPa, about two times that of neat CS/PEO nanofibers. Uniformly dispersed Pd nanoparticles in size of about 1.6 nm have been successfully immobilized on the composite nanofiber with a solution impregnation process. With a loading as low as 0.2 mol% of Pd, the resultant Pd@CS/PEO/TiCT composite nanofiber catalysts were highly active for both Heck and Sonogashira coupling reactions with broad reactants application scope, and could be recycled 15 runs without significant loss of activities.