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Page 8 of 27 He et al. Soft Sci 2024;4:37 https://dx.doi.org/10.20517/ss.2024.32

As a result, MOF crystals develop within the pores of the hydrogel, leading to the formation of MOFs-based
[67]
hydrogel composites . This synthesis strategy presents a distinctive opportunity to customize the structure
and properties of the composite material, enabling improved functionality and performance in targeted
applications such as drug delivery and catalysis. The in-situ growth method represents an innovative
strategy for designing and synthesizing advanced materials with exceptional properties.

APPLICATION
The MOFs-based hydrogels show their multifaceted utility across various domains, including five key areas
of application: electrocatalysis, water treatment, detection and sensors, biomedical applications with a focus
on antibacterial properties, wound healing, and drug delivery, and finally, miscellaneous applications that
highlight the adaptability and innovation potential of MOFs-based hydrogels [Figure 4]. Each section
unfolds a distinct facet of the functionality of hydrogels, demonstrating their capacity to address complex
challenges and contribute to advancements in fields ranging from environmental remediation to
healthcare .
[68]

Catalysis
The porous architecture of MOF-based hydrogels offers numerous surfaces and channels, facilitating
[69]
efficient adsorption of reactants onto catalytic sites . The metal ions in MOFs provide electrons and
actively participate in reactions, with metal centers typically showing catalytic activity for specific reactions.
Studies have demonstrated that both pyridinic and graphitic nitrogen serve as highly effective active sites.
Wang et al. utilized carrageenan/NiCo-MOF hydrogels as precursors to synthesize porous carbon aerogels
(Ni S -Co S /NCAs) as electrocatalysts for the oxygen evolution reaction (OER) . Electrochemical tests
[70]
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[Figure 5A], revealed outstanding catalytic performance, surpassing most transition metal sulfide catalysts,
with an overpotential of just 337 mV. This high performance can be attributed to the large surface area, the
interfacial synergy between Ni S and Co S , and the unique 3D porous structure, which offers numerous
3 2
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active sites and enhances mass transport and electron mobility after freeze-drying. Sikdar et al. developed a
scalable method based on “hydrogel-organic interfacial diffusion” for the direct growth of MOF
nanocrystals on porous graphene hydrogels, enabling precise control over structure . Molecular dynamics
[71]
simulations indicated that the two-stage diffusion process plays a critical role in the tunable formation of
MOF-based hydrogels. The resulting hydrogel-derived aerogels exhibited excellent performance in the
OER, with high operational stability, a low overpotential, and a small Tafel slope, reflecting a fast OER rate.
These studies emphasize the importance of tailored synthetic approaches, unique nanoscale structural
designs, and the interplay of materials in improving catalytic performance. From the well-distributed Fe
elements in mesoporous carbon sheets to the core-shell structure of N-doped carbon nanotubes and the
hierarchical porous structure with interfacial synergy in carrageenan/NiCo-MOF hydrogels, each
contribution provides valuable insights. Collectively, these advancements underscore the versatility and
promise of MOF-based hydrogels in advancing the field of electrocatalysis.

Ma et al. developed MOF-based hydrogels capable of rapidly degrading organophosphorus chemicals under
ambient conditions, introducing a range of hydrogels with diverse functions and topologies . Among
[24]
these, MOF-808 exhibited the highest efficiency in hydrolyzing organophosphorus compounds. Hydrogels
incorporating MOF-808 were able to rapidly degrade both simulated and real nerve agents, with the shortest
degradation half-life reported among MOF-based hydrogels. This study provides a significant breakthrough
in the design of protective devices for rapid detoxification. In a related development, Weng et al.
synthesized novel MOF-hydrogel microspheres, demonstrating a synergistic effect between the hydrogel
and the MOF layer [Figure 5B] . The porous hydrogel matrix created a biocompatible environment for
[72]
encapsulated enzymes, preventing undesirable restrictions and chemical interactions, allowing the enzymes