Low-cost synthesis of Ti3C2Tx MXene-based sponge for solar steam generation and clean water production

MXenes are layered 2D materials with fascinating properties such as large surface area, good electrical conductivity, good chemical, and electrochemical stabilities, etc. However, the high cost of MAX phases remains a major bottleneck for the large-scale synthesis of Ti3C2Tx MXene for industrial applications. This motivated us to strategically design a method for the large-scale synthesis of Ti3C2Tx MXene using low-cost waste-derived precursors. Initially, we used carbon soot obtained from car exhaust as a low-cost carbon precursor for the synthesis of the Ti3AlC2 MAX phase. Further, the Ti3C2Tx MXene is synthesized from this MAX phase with better purity. Furthermore, the Ti3C2Tx MXene-activated carbon (AC) composite is prepared and coated over a natural biodegradable sponge (NBS) in order to use it as an efficient photothermal/solar absorber to produce steam using solar energy. The NBS layer exhibits a microporous structure that provides adequate water transportation and concentrated heat for interfacial water evaporation whereas the Ti3C2Tx MXene and AC provide large surface area and stability to the absorber. The Ti3C2Tx MXene-AC@NBS composite successfully produced solar evaporation rates of up to 1.8 kg m2/h with a solar steam conversion efficiency of 89.82 % with one sun solar irradiation.