Ultralight anisotropic Ti3C2Tx MXene/Carbon nanotube hybrid aerogel for highly efficient solar steam generation

Abstract

Solar steam generation (SSG) has been considered as a promising method to produce fresh water from seawater. Due to high light absorption and excellent chemical stability, carbon nanotube (CNT) has been widely used for SSG. However, it is still challenge to simultaneously realize high water evaporation rate and energy efficiency for CNT based solar steam generator. Herein, ultralight anisotropic Ti₃C₂T_x MXene/carbon nanotube (A-Ti₃C₂T_x/CNT) aerogels are designed and fabricated for highly efficient SSG. The combination of CNT and Ti₃C₂T_x MXene endows the hybrid aerogel with high light absorption and effective localized surface plasmon resonance (LSPR), resuting in enhanced light-to-heat conversion efficiency. The porous structure of aerogel leads to multiple scattering and absorption, further contributing to the photothermal conversion process. Moreover, the low thermal conductivity of aerogel structure effectively reduces the heat loss to environment. Through tailoring the anisotropic channel, the A-Ti₃C₂T_x/CNT hybrid aerogel with average channel size of 80 μm possesses most efficient water transport due to the capillary effect and formation of intermediate water. Therefore, the A-Ti₃C₂T_x/CNT hybrid aerogel exhibits high average light absorption of 95.68% in the wavelength range of 200–2500 nm, excellent water evaporation rate of 2.10 kg m⁻² h⁻¹ under 1 sun irradiation (1 kW m⁻²) with a high energy efficiency of 93.4%, and remarkable durability with 7 days continuous water evaporation. The A-Ti₃C₂T_x/CNT hybrid aerogel also shows high resistance to salt crystallization due to its high salt transport flux of 1.90 kg m⁻² h⁻¹. This work offers a prospective strategy for constructing highly efficient solar steam generator with stable performance for practical application in seawater desalination.