Synergistic Photocatalytic-Photothermal Contribution Enhanced by Recovered Ag+ Ions on Mxene Membrane for Organic Pollutant Removal

This work developed a synergistic photocatalytic-photothermal system based on two-dimensional Ti 3 C 2 T x MXene (TCM) membrane for simultaneous recovery of Ag + ions and removal of aqueous rhodamine B (RhB). The photo-reduction of Ag + ions into Ag nanoparticles with the conversion rate up to 100% was achieved on TCM membrane under visible-light irradiation. These Ag nanoparticles uniformly deposited on the surface and interlayers of TCM membrane. It facilitated the separation of photo-generated charges for forming more active species, including both ∙O 2 - and ∙OH radicals, to oxide RhB molecular. At the same time, the surface plasma effect of Ag nanoparticles enhanced the light adsorption and photothermal conversion efficiency (~81%) on the TCM membrane. Conversely, photothermal effect was beneficial for further enhancing the reaction rate of both reduction of Ag + ions and photo-oxidation of RhB by concentrating the solution and promoting the electron transfer.