Ultrafast and cost-effective synthesis of ZnO@CoZn-ZIF/MXene nanocomposite via cold plasma treatment for advanced photocatalytic applications

In this attitude, a novel ZnO@CoZn-ZIF/MXene nanocomposite was constructed using an ultrafast and cost-effective method via cold plasma treatment for the degradation of methylene blue (MB). Initially, Cr2CTX nanosheets were synthesized through etching of the Cr2AlC phase. Subsequently, the bimetallic metal-organic framework CoZn-ZIF (BZIF) was prepared both individually and hybridized with MXene (BZIF/Cr2C) via a rapid nucleation approach. Thereafter, zinc oxide (ZnO) nanoparticles were deposited onto the BZIF/Cr2C surface using two methods: conventional hydrothermal/sol-gel (HS) and the novel cold plasma treatment (CP). The analyses revealed that the CP method resulted in more uniform distribution of ZnO nanoparticles, stronger chemical bonding (facilitated by APTES silane coupling agent), and reduced charge recombination compared to the HS method. FESEM images confirmed the formation of distinct phases and poor integration for the hydrothermal method, whereas the plasma-synthesized sample demonstrated a highly integrated and well-ordered structure. XPS and FTIR analyses confirmed the presence of strong bonds such as Cr-O-Si and Zn-O in the plasma-treated sample. Photocatalytic investigations demonstrated that the ZnO@BZIF/Cr2C-CP nanocomposite exhibited the highest MB degradation efficiency under both UV/Visible light (99% and 100% within 120 min, respectively), attributed to its suitable band gap (2.85 eV), reduced charge recombination, and effective generation of reactive species (hydroxyl and superoxide radicals). Electrochemical tests (EIS and current density) confirmed lower charge transfer resistance and higher electrochemical activity for the plasma-synthesized sample. The proposed charge transfer mechanism follows a Z-scheme pathway, preserving the strong oxidation power of ZnO and the reducing ability of electrons in MXene. Finally, epoxy coatings containing this nanocomposite (ER-ZnO@BZIF/Cr2C-CP) not only exhibited excellent photocatalytic activity (color change Δb* value of 51 under visible light) but also demonstrated significant improvements in mechanical properties including tensile strength (5.4 N/mm2), storage modulus (1943 MPa), and toughness (14.7 mJ/mm2) compared to neat epoxy resin. These results introduce the cold plasma-synthesized nanocomposite as an ideal candidate for water treatment applications and self-cleaning coatings. Ultrafast and cost-effective fabrication of ZnO@BZIF/Cr2C coatings using cold plasma technology. Cold plasma treatment significantly enhanced interfacial bonding, leading to a high product yield of 98%. The plasma-treated composite exhibited superior photocatalytic stability, retaining 87% efficiency after 10 cycles. Improved mechanical and thermal properties compared to conventional hydrothermal and sol-gel methods. The synthesized coatings exhibit exceptional performance in Methylene Blue degradation.