Renewable pickering emulsion system based on bifunctional materials for highly efficient fuel oil desulfurization without stirring

The mass transfer resistance at liquid (oil)-liquid (extractant) interface seriously limits the reaction rate and desulfurization efficiency in extraction-catalytic oxidative desulfurization (ECODS), and the catalyst is difficult to be recycled in the homogeneous system. Herein, we demonstrated a renewable Pickering emulsion system with enlarged interfacial contact area to overcome the mass transfer resistance. The bifunctional materials were designed based on Janus graphene oxide (GO) 2D-sheets, amino-modified SBA-15 (NH2-SBA-15) mesoporous microspheres and H3PW12O40 (HPW), as both catalysts and emulsion stabilizers to establish the catalytic emulsion system. Excellent amphiphilicity was endowed by the anisotropic Janus structure of prepared mate-rials, which could convert the oil/extractant bi-phase into a stable Pickering emulsion. The interfacial contact area was skillfully enlarged in emulsion due to formed micro emulsion droplets and empty channels between the droplets, and the catalyst could be easily recycled by centrifugation. Besides, the unique properties of catalyst including large specific surface area, adequate exposed catalytic active sites and high pore volume could also shorten the reaction path and facilitate the rapid diffusion of reactants and products. This opens the door to the application of Pickering emulsion in ECODS fields based on the design of bifunctional materials.