Electrospinning Device for Nanofibers| Binder-Freelmmobilization ofPhotocatalyst on Membrane Surface forEfficient PhotocatalyticH20,ProductionandWater Decontamination

Research Background
Photocatalysis, as a green and clean catalytic technology, holds great potential in environmental remediation, chemical synthesis, and renewable energy. Recent advancements have significantly improved the light utilization and catalytic performance of photocatalyst materials, yet practical applications still face challenges. Suspended particle photocatalysts suffer from issues like sedimentation and loss, while immobilized photocatalysts (via binder crosslinking or direct mixing with substrates) exhibit limited catalytic site exposure and low light utilization efficiency, leading to reduced overall photocatalytic activity.

Content Summary
To address these challenges, Prof. Li Wenwei’s team at the University of Science and Technology of China proposed a novel binder-free surface self-immobilization strategy for constructing photocatalytic membranes. The team soaked polyvinylidene fluoride (PVDF) support membranes in the organic solvent N,N-dimethylformamide (DMF) to soften and expand the membrane fibers, enlarging micropores to trap particle catalysts. Subsequent DMF evaporation caused fiber contraction, firmly immobilizing photocatalyst particles on the membrane surface. The study, titled *"Binder-Free Immobilization of Photocatalyst on Membrane Surface for Efficient Photocatalytic H2O2 Production and Water Decontamination,"* was published in *Nano-Micro Letters (IF 31.6)*. Results showed that the surface self-immobilized photocatalytic membrane (SSPM) exhibited 4.6-fold higher activity than traditional embedded membranes (MEPM) and demonstrated excellent long-term stability. TheSSPM-based UV/H2O2 process enabled efficient purification of various water bodies, highlighting its practical potential.

Highlights

1. Innovation: A binder-free surface self-immobilization strategy achieved high-activity photocatalytic membranes. DMF-treated PVDF membranes underwent "expansion-contraction," trapping and binding CoOx/Mo:BiVO4/Pd particles while maintaining high exposure.

2. Enhanced Activity & Stability: SSPM showed 4.6x higher H2O2 production than MEPM and superior stability in continuous operation.

3. Broad Applications: SSPM-based processes enable efficient H2O2 synthesis and in-situ use for rapid micro-pollutant removal, advancing photocatalytic water treatment.

Graphical Abstract

1. SSPM Preparation & Characterization: DMF-treated PVDF membranes trapped catalysts via fiber expansion-contraction (Fig. 1a). SEM/EDS (Fig. 1b–c) confirmed surface-localized catalysts, unlike MEPM’s internal dispersion. High-magnification SEM (Fig. 1d) showed PVDF fiber-wrapped particles. Directly filtered membranes (SUPM) lost catalysts under flow (Fig. S6).

Fig. 1. (a) SSPM preparation. (b–d) SSPM SEM/mapping. (e–g) MEPM SEM/mapping.

2.H2O2 Production: SSPM’s high catalyst exposure yielded 4.6x higher H2O2 activity than MEPM (Fig. 2a) and stable performance over 20 cycles (Fig. 2b), while SUPM lost 54.7% activity after 10 cycles.

Fig. 2. (a) H2O2 activity. (b) Cyclic stability. (c) Mass flow/catalyst fixation. (d) Benchmarking. (e) Continuous-flow H2O2 yield.

3.Reactant Accessibility & Diffusion: Simulations revealed oxygen diffusion limitations in MEPM (Fig. 3a). SSPM’s hydrophobic surface promoted H2O2 desorption, preventing decomposition (Fig. 3b–c).

Fig. 3. (a) Oxygen distribution. (b) H2O2 decomposition. (c) H2O2 yield. (d) Hydrophobicity mechanism.

4.Pollutant Degradation: SSPM/UV completely removed 10 mg/L tetracycline (TC) and bisphenol A (BPA) within 1 hour (Fig. 4a), 10x faster than UV alone. It maintained efficiency in real water matrices (lake, tap, and wastewater; Fig. 4b) and continuous-flow stability (Fig. 4d).

Fig. 4. (a) Pollutant removal. (b) Real-water performance. (c) Setup. (d) Continuous-flow removal.

Conclusion
This study developed a binder-free surface self-immobilization strategy to overcome performance decay in traditional methods. SSPM enabled efficient pollutant removal via UV/H2O2 processes, advancing practical photocatalytic water treatment and inspiring catalytic membrane design.

Original Link: https://doi.org/10.1007/s40820-025-01822-0