As a 2D nanomaterial with high hydrophilic and co-catalytic properties, MXene has been widely studied in the field of membrane separation and advanced oxidation. However, its susceptibility to oxidation in catalytic environments poses a significant challenge to its long-term stability and performance. Therefore, constructing an oxidation-resistant MXene catalytic membrane technology and ensuring its excellent flux and catalytic performance are important for the practical application of MXene membranes. Herein, we prepared a cobalt monoatomic intercalated M/E0.1-Co catalytic separation membrane by mild reduction of epigallocatechin-3-gallate (EGCG). EGCG not only connects the MXene lamellae during filtration through strong hydrogen bonding, but also protects the chemical stability of the MXene substrate through its antioxidant ability. Furthermore, the trace amount of EGCG in the confined domain space also promotes the rate-limiting step of the transition from the high-valent state to the low-valent state in Co single-atom catalysis. The stability of the catalytic separation layer was ensured along with a 100% degradation performance of sulfamethoxazole. This study establishes a bridge between the catalytic oxidation and chemical stability of a wide range of MXene-based materials nowadays and provides a viable proposal for the practical application of long-term utilized MXene materials in catalysis.
Achieving low reflection loss, broad absorption bandwidth and lightweight remains a major challenge for electromagnetic wave absorption (EWA) materials. In this work, the lightweight multifunctional polyimide composite aerogels reinforced with two-dimensional Co-anchored MXene (Co/MXene) and one-dimensional CoFe 2 O 4 -decorated carbon nanofibers (CoFe 2 O 4 /CNF) were successfully prepared for high-performance EWA. The dielectric and magnetic losses were significantly improved due to the unique heterogeneous porous structure in the composite aerogels. The aerogels achieve a minimum reflection loss of -59.4 dB at 7.6 GHz with a thin thickness of 2.31 mm, and the effective absorption bandwidth could be 4.24 GHz with an ultrathin thickness of 1.25 mm. The outstanding EWA performance can be attributed to the synergistic contribution of conductive loss, interfacial polarization loss, dipole polarization loss and magnetic loss. Moreover, the porous PI framework plays a crucial role in optimizing impedance matching and structural stability. The composite aerogels also demonstrate potential for radar stealth and thermal insulation. This work presents a new strategy for designing multifunction EWA materials.
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