Molybdenum Carbide/Carbon-Based Chitosan Hydrogel as an Effective Solar Water Evaporation Accelerator

Abstract

Solar-driven water evaporation is deemed to be a green and sustainable strategy to cope with the global freshwater crisis. However, effective water evaporation to achieve high water yield in practical application is significant but usually neglected. Here, a molybdenum carbide/carbon-based chitosan hydrogel (MoCC-CH) is designed not only as a solar absorber but also as a water evaporation accelerator. The proportion of the chitosan matrix in the hydrogel is tunable to acquire low-tortuosity channels for facilitating solar-driven evaporation. Thus, the evaporation rate of MoCC-CH is up to ∼2.19 kg m–2 h–1, and a corresponding solar-thermal conversion efficiency of 96.15% is obtained under one sun illumination. The highly efficient water generation is also attributed to a novel water collection device and valid cooling strategy. The outdoor experiment possesses an excellent daily freshwater yield of 13.86 kg m–2 in one sunny day. The successful demonstration of both the well-designed hybrid hydrogel and an optimized passive solar desalination system offers the possibility for sustainable solar-driven desalination.

Nanoenabled Photothermal Materials for Clean Water Production

“…q i represents the solar intensity under 1 kW m −2, while C opt corresponds to multiple intensities of applied solar energy. [ 13,19,34,37 ] Finally, the plasmonic effects of plasmonic metals have specific wavelengths and are highly dependent upon shapes and sizes. [ 13,35 ] Metal nanoparticles with a large scale or different ways are combined in certain symmetry to obtain a broad range of solar power.…”

“…[ 4,28,38 ] Several classes of carbon‐based absorber such as graphene oxide (GO), carbon black, graphite, carbon composites, carbon nanotubes (CNTs), and amorphous carbons exhibit outstanding solar to heat conversion capability owing to their vital inherent characteristics instead of metallic plasmon. [ 37,39–42 ] The exceptional photothermal ability, minimum reflection and emittance, and excellent absorbance enabled carbon‐based materials as an efficient vapor generator. Moreover, the availability and cost‐effectiveness signify the importance of carbon‐based nano‐absorber, and they can endure acid, salty, and alkali environments.…”

Enhanced Steam Temperature Enabled by a Simple Three‐Tier Solar Evaporation Device

“…[ 1,2 ] Recent years, the interfacial water evaporation technology (IWET) relying on photothermal materials and solar energy has gradually stepped into public views for solving the problem of clean water shortage. [ 3–8 ] With regards to the studies on high‐efficiency evaporation and sewage treatment, researches have made good progress through macrostructure control, including thermal management (weakening of heat radiation and conduction, [ 9–13 ] environmental heat utilization [ 14–16 ] ), water channel designs (1D water channel, [ 17–19 ] 2D water channel, [ 20–22 ] hydrophilic porous aerogel or hydrogel, [ 23–26 ] etc. ), and hydrophile‐hydrophobic control designs.…”

Intensifying sustainable solar water production by steam heat internal circulation

“…[7][8][9][10][11] The interfacial evaporators are crowned by strong solar energy acquisition, orderly water supply, and efficient heat arrangement. [12][13][14][15][16][17] The problems of high-rate evaporation and salt treatment have been solved in multiple ways through the selection of photothermal materials or systems and the clever design of macrostructures. [18][19][20][21][22][23][24][25] However, in the process of interfacial evaporation for practical application, the storage of waste heat, is truly advantageous for the sustainable development of solar-driven evaporation technology.…”