Self-assembled core-shell polydopamine@MXene with synergistic solar absorption capability for highly efficient solar-to-vapor generation

Abstract

As a renewable and environment-friendly technology for seawater desalination and wastewater purification, solar energy triggered steam generation is attractive to address the long-standing global water scarcity issues. However, practical utilization of solar energy for steam generation is severely restricted by the complex synthesis, low energy conversion efficiency, insufficient solar spectrum absorption and water extraction capability of state-of-the-art technologies. Here, for the first time, we report a facile strategy to realize hydrogen bond induced self-assembly of a polydopamine (PDA)@MXene microsphere photothermal layer for synergistically achieving wide-spectrum and highly efficient solar absorption capability (~ 96% in a wide solar spectrum range of 250-1,500 nm wavelength). Moreover, such a system renders fast water transport and vapor escaping due to the intrinsically hydrophilic nature of both MXene and PDA, as well as the interspacing between core-shell microspheres. The solar-to-vapor conversion efficiencies under the solar illumination of 1 sun and 4 sun are as high as 85.2% and 93.6%, respectively. Besides, the PDA@MXene photothermal layer renders the system durable mechanical properties, allowing producing clean water from seawater with the salt rejection rate beyond 99%. Furthermore, stable light absorption performance can be achieved and well maintained due to the formation of ternary TiO 2 /C/MXene complex caused by oxidative degradation of MXene. Therefore, this work proposes an attractive MXene-assisted strategy for fabricating high performance photothermal composites for advanced solar-driven seawater desalination applications.

Biomimetic Ultra‐Black Sponge Derived from Loofah and Co‐MOF for Long‐Term Solar‐Powered Vapor Generation and Desalination

“…Solar‐powered vapor generation and desalination, which is an economical strategy that mainly utilizes solar energy and ultra‐black materials with efficient light absorption and photothermal conversion properties in solar band, is used to powerfully accelerate the evaporation of water and collect water and thereby solve the crises of drinking water shortage and water pollutions. [ 18–21 ] In the last few years, some evaporators based on different photothermal materials such as metal nanoparticles, [ 22–26 ] semiconductors, [ 27–30 ] polymers, [ 31–35 ] carbon materials, [ 36–48 ] and MXene [ 49–52 ] have been reported. However, most evaporators with high water evaporation rates and photothermal conversion efficiencies have some limitations in practical application scenarios, such as the use of expensive metals (Au and Ag) to enhance light absorption and photothermal conversion, strict and complex preparation processes to achieve microstructural control, and poor durability when used for solar‐powered desalination.…”

Preparation Strategies and Applications of MXene‐Polymer Composites: A Review

“…For example, MXene nanosheets could be adsorbed onto polydopamine (PDA) microspheres through hydrogen bonding to form a coreshell PDA@MXene composite microsphere (Figure 2b). [54] After filtration, these microspheres could be processed into thin films with 3D interconnected channels, which provided diffusion paths for water molecules when the PDA@MXene films was used in solar steam generation systems.…”

“…Reproduced with permission. [54] Copyright 2019, Springer Nature. c) Schematic illustration of the interaction of polymer with Ti 3 C 2 T x layers.…”

“…MXene has been demonstrated to have unique and appealing photothermal properties, [31,33,139] which shows almost complete absorbance for visible and near-infrared light due to the localized surface plasmon resonance effect. [40,54,140] Owing to the good photothermal conversion performances, MXene-polymer composites can be widely used in solar water desalination, [32] solar photothermal electrodes, [141] biomedical applications, [142] smart hydrogels, [143] and light-driven actuators. [144] The MXene-polymer based interfacial solar steam generation systems have been developed to absorb solar energy and heat seawater to form and collect steam at the air/water interface.…”

Quasi‐Ordered Nanoforests with Hybrid Plasmon Resonances for Broadband Absorption and Photodetection

“…absorption over a wide range of wavelengths have been explored for optoelectronic and photothermal applications. [1][2][3][4][5][6][7][8][9] For instance, micro-or nano-structures based on titanium dioxide (TiO 2 ), silicon (Si), silver (Ag), and aluminum (Al), have been demonstrated with near-blackbody absorption properties in previous studies. [10][11][12][13][14][15][16][17] Among them, black silicon is a typical type of these structures and can achieve visible light absorption of up to ≈90%.…”