Innovative ag-AgCl@TiO2@cellulose nanofiber porous composites with Z-scheme heterojunction for enhanced adsorption and photocatalytic degradation of formaldehyde

Photocatalysis has emerged as one of the most promising technologies for formaldehyde purification owing to its green, safe, and cost-effective properties. However, most photocatalysts exhibit poor light absorption properties and exist as powders, limiting their large-scale application. To address this challenge, Ag-AgCl@TiO₂@cellulose nanofiber porous composites were prepared by integrating the photocatalysts into a cellulose matrix through physical/chemical dual crosslinking, photoreduction, and freeze-drying. The materials exhibited excellent mechanical properties due to the hydrogen bonding and electrostatic adsorption interactions between the components. Moreover, the porous composites exhibited excellent synergistic adsorption–photocatalytic degradation performance for formaldehyde. This is attributed to the abundant polar functional groups in the cellulose nanofibers and the heterostructure formed by TiO₂, Ag, and AgCl. The composites achieved a maximum photocatalytic degradation rate of 99.54 %. After five cycles of reuse, they still maintained a high degradation efficiency of 99.07 %, demonstrating excellent recyclability. Compared with similar materials, the synthesized porous composites performed well in terms of degradation rate, maximum degradation efficiency, and cyclic reutilization performance. In summary, this study provides an innovative approach to air purification.