Enabling Continuous and Improved Solar-Driven Atmospheric Water Harvesting with Ti₃C₂-Incorporated Metal–Organic Framework Monoliths

Abstract

Solar-powered atmospheric water harvest (SAWH) with metal–organic frameworks (MOFs) represents one of the most sustainable, energy-efficient, and low-cost ways to alleviate water shortage stress in arid regions. However, the daily water productivity of previously developed SAWH devices remains low as they are merely allowed to be operated in batch mode and complete one water harvest cycle every day. This inevitably makes it rather challenging to deploy MOF-based SAWH for water production at scales. To overcome this challenge, MXene Ti3C2-incorporated UiO-66-NH2 (TUN) cylindrical monoliths (13 mm diameter, 4 mm thickness) with vertically aligned porous networks have been prepared and exhibited greatly enhanced solar heating capacity and atmospheric water adsorption/desorption kinetics. Using TUN monoliths as atmospheric water adsorbents, a novel SAWH device containing a flippable adsorbent stage with dual TUN monolith layers attached on both sides has been fabricated. Such a novel design enables the prototype to produce water in a continuous mode under sunlight irradiation, delivering 57.8 mLH2O kgMOF –1 h–1 of water productivity in a simulated indoor arid environment (20% relative humidity, 298 K). This is the first exploration in continuous water production with MOF-based SAWH, demonstrating a promising way to achieve scalable and low-cost SAWH in arid areas.

Assemblable Carbon Fiber/Metal–Organic Framework Monoliths for Energy-Efficient Atmospheric Water Harvesting

“…This suggested that the cross-linked SA network rendered a limited effect on the porosity of Al-Fum, well matching previous reports. 18,28 In comparison to the well isolated pristine Al-fum crystals (Figure S2), scanning electron microscopy (SEM) observations on the cross section of CAS-3 clearly revealed that Al-fum crystals were well accommodated in the cross-linked SA polymer network (Figure 2d). This was further supported by the elemental mapping analysis where the Al element from Al-Fum and the Ca element from the crosslinked SA network were clearly visualized in CAS-3 (Figure 2e).…”

“…19,20 Although our recently designed AWH devices enabled us to continuously produce water through multiple WHCs during the daytime, the operation of such a device still heavily depended on the availability of sunlight. 28 This inevitably limited the scaling up of water productivity of the devices with solar heating-driven AWH technology.…”

Rational Design of Coordination Bond Connected Metal Organic Frameworks/MXene Hybrids for Efficient Solar Water Splitting

“…One of the adjacent lattice fringes distance is equal to ≈0.25 nm which corresponds to the (102) plane of the single-layer Ti 3 C 2 , whereas the other one was equal to ≈0.32 nm, which is associated with the (316) plane of UZT. [37] The images of elemental mapping demonstrated that Ti, Zr, C, and O are detected and are densely dispersed in the composite, indicating the successful formation of UZT/CFMX. The distribution of F element is not obvious, demonstrating that the HF etchant has been cleaned up in the composite (Figure 1i-n).…”

“…One of the adjacent lattice fringes distance is equal to ≈0.25 nm which corresponds to the (102) plane of the single‐layer Ti 3 C 2 , whereas the other one was equal to ≈0.32 nm, which is associated with the (316) plane of UZT. [ 37 ]…”

Sustainable water generation: grand challenges in continuous atmospheric water harvesting

“…The majority of these introduced batch water generation. 28,[69][70][71][72] Recently only one conceptual truly continuously operated prototype has been tested under laboratory conditions using artificial light. 20 The first step towards continuous AWH was to achieve multiple sorptiondesorption cycles in batches.…”