Magnetic separation of photocatalysts holds great promise for water treatment. A magnetic separation method has a positive effect on the recovery of catalysts after degradation. In this paper, an efficient and reusable catalytic system is developed based on coating magnetic Fe₃O₄ by depositing Fe²⁺ on the surface of ZnO. The Fe₃O₄/ZnO nanocomposite exhibits enhanced performance for organic pollutant degradation. The Fe₃O₄/ZnO system demonstrates a high photocatalytic activity of 100% degradation efficiency in Rhodamine B (RhB) degradation under UV light irradiation for 50 min. The excellent photocatalytic activity is primarily due to the separation of photogenerated electron-hole pairs being facilitated by the strong interaction between Fe₃O₄ and ZnO. The induction of the magnetic Fe₃O₄ endows the Fe₃O₄/ZnO composite with superior magnetic separation capability from water. Experiments with different radical scavengers revealed that the hydroxyl radical (·OH) is the key reactive radical for the effective degradation of RhB. This work innovatively affords a common interfacial dopant deposition strategy for catalytic application in the degradation of organic dye pollutants and catalyst separation from wastewater efficiently.

Oriented TiO₂ nanotubes, which are fabricated by anodic oxidation method, are prospective in photoelectrochemical analysis and sensors. In this work, Pt and IrO₂ co-modified TiO₂ nanotubes array was prepared via a two-step deposition process involving the photoreductive deposition of Pt and chemical deposition of IrO₂ on the oriented TiO₂ nanotubes. Due to the improved separation of photo-generated electrons and holes, Pt-IrO₂ co-modified TiO₂ nanotubes presented significantly higher PEC activity than pure TiO₂ nanotubes or mono-modified TiO₂ nanotubes. The PEC sensitivity of Pt-IrO₂ co-modified TiO₂ nanotubes for glutathione was also monitored and good sensitivity was observed.

Ethylene (C₂H₄) is a vital industrial chemical with a growing market, similarly produced through the steam cracking of hydrocarbons, such as ethane (C₂H₆). However, separating C₂H₄ from a C₂H₆ and C₂H₄ mixture remains challenging due to their similar molecular sizes and boiling points, necessitating highly energy-intensive processes such as cryogenic distillation. This study introduces two ultramicroporous metal–organic frameworks (MOFs), NKMOF-17-Co and NKMOF-17-Cu, synthesized rapidly under ambient conditions as efficient materials for C₂H₆/C₂H₄ separation via physical adsorption. Gas adsorption experiments reveal that NKMOF-17-Co and -Cu exhibit a preference for adsorbing C₂H₆ over C₂H₄. Determined by these single crystal structures of loading gases into NKMOF-17-Co and -Cu, stronger hydrogen bonding and C–H···π interactions between C₂H₆ and MOFs were confirmed clearly. Verified by breakthrough tests of a C₂H₆ and C₂H₄ mixture for NKMOF-17-Co and -Cu, C₂H₄ was obtained in high purity (>99.96%). NKMOF-17-Co and -Cu were regenerated with low energy requirements and showed stable performance under repeated cycling tests. These findings suggest that NKMOF-17-Co and -Cu hold great promise for energy-efficient separation processes in the industrial separation of C₂H₆ and C₂H₄.