Aqueous Stable Ti 3 C 2 MXene Membrane with Fast and Photoswitchable Nanofluidic Transport

High, stable, and modulatable ionic conductivity is important for many nanofluidic applications of layered two-dimensional (2D) membranes. In this study, we demonstrate a proton and ionic conductivity of the Ti 3 C 2 T x membrane that is orders of magnitude higher than that of bulk solution at low concentrations. Importantly, the membrane is highly stable in aqueous solution without any modification, due to the strong and attractive interlayer van der Waals interaction and weak electrostatic repulsive interaction. Furthermore, by exploiting the intrinsic photothermal property of MXene, we demonstrate that the ionic conductivity can be reversely, rapidly, and completely switched on or off with laser light. This study should prove MXene membrane as a suitable platform to study and utilize nanofluidic ion transport. It should also inspire future studies to manipulate the mass transport through 2D membranes using their inherent physicochemical properties

Electricity generation based on a photothermally driven Ti3C2Tx MXene nanofluidic water pump

A popular method to harvest solar power is to convert light to heat, then to the kinetic energy of water, and finally to electricity, so-called concentrating solar power. However, it requires highly bulky components, limiting the applications. In this study, we present a miniaturized nanofluidic version—simply placing a MXene film on ionic solution and exposing part of the film to light. The distinguished photothermal property of MXene converts the asymmetric light irradiation to a water evaporation gradient, pumping water through the nanofluidic channels in the film, which transports cations and results in an ionic current. We expect this study to inspire more studies to explore the possibility of nanofluidic photothermal electricity as an alternative solar electricity technology for dispatched electricity generation and powering microfluidic/nanofluidic devices

Fast and all-weather cleanup of viscous crude-oil spills with Ti3C2TXMXene wrapped sponge

Remediation of crude-oil spills is a global challenge. Conventional sorbents are inefficient for complete remediation due to the high viscosity of crude oil. However, heating crude oil can dramatically reduce viscosity, allowing efficient remediation. In this study, we demonstrate that polyurethane sponge wrapped with Ti3C2TXMXene (Ti3C2TX@PU) realizes fast and complete remediation of crude oil with the help of Joule heating or photothermal effects. Due to excellent photothermal properties and metal-like conductivity of Ti3C2TX, Ti3C2TX@PU can quickly adapt to the various conditions in practical applications with the synergistic effect of solar heating and Joule heating. The excellent heating capacity enables Ti3C2TX@PU to absorb more than 40 times its own weight of crude oil in 20 min. This all-weather sorbent design provides a promising solution for the cleanup of viscous crude-oil spills