Linker Encouraged Solid State Synthesis of MOF Derived Z-Scheme NiCo₂O₄/NiO/C toward Efficient Removal of Organic and Inorganic Pollutants from Water

Here, we represent a solid-state route for the construction of MOF derived multifunctional Z-scheme NiCo₂O₄/NiO/C applied for the photocatalytic removal of methylene blue (dye) and tetracycline (drug) and the reduction of Cr(VI) (heavy metal). The developed solid-state method yielded a highly effective NiCo₂O₄/NiO/C catalyst by mechanically grinding independently produced Ni and Co-MOFs and subsequently pyrolyzing them. The use of different linkers in the Ni MOF (H₃-BTC linker) and Co-MOF (2-methylimidazole linker) proved to be effective in constructing the NiCo₂O₄/NiO/C composite, ensuring a nonaggregated distribution on a carbon framework. Such a synthesized Z-scheme NiCo₂O₄/NiO/C composite has performed exceptionally well to achieve excellent degradation of MB (98.23% in 120 min) and TC (92.85% in 25 min) and Cr(VI) reduction (98.22% in 20 min), with excellent recyclability and stability. The NiCo₂O₄/NiO/C composite, synthesized using Ni and Co-MOFs prepared with different linkers, outperformed its counterpart prepared using Ni and Co-MOFs with identical linkers (either 2-methylimidazole or H₃BTC). This study paves the way for the future synthesis of MOF derived bimetallic composites for photocatalytic applications.