Study on Pickering emulsions co-stabilized by multiple particles for building MXene-based multifunctional composite foam

Abstract

Pickering emulsion, an emulsion prepared by replacing conventional surfactants with solid particles, has been extensively used to construct a variety of functional materials especially 3D porous foams or aerogels. Ti3C2Tx MXene have recently garnered tremendous attention and considered as a promising candidate for the construction of functional nanomaterials due to their fascinating properties. However, it remains a challenge to construct MXene-based composite porous materials. Herein, the Pickering emulsion co-stabilized by multiple kinds of particles and the subsequent MXene-based multifunctional composite foam were studied. The formation mechanism of Pickering emulsions stabilized by cellulose nanofibrils (CNF), nickel nanowires (Ni NW), and Ti3C2Tx MXene was investigated along with their stabilization mechanism in a complex water-oil environment. The final Pickering emulsions exhibited excellent stability over a wide pH range (5−11) and ionic strength (0–400 mM). Further, the CNF/MXene/Ni (CMN) composite foam was prepared by freeze-drying the emulsion gel. The as-prepared foam exhibited a minimum reflection loss of −30.2 dB at 2.8 GHz frequency. Moreover, the foam also exhibited promising photothermal conversion behavior, maintaining a temperature of up to approximately 80.9 °C for 200 s of exposure to 1 Sun. Therefore, this work affords a new and universal method to prepare MXene-based multifunctional porous materials for their potential applications in many areas.