Amine-functionalized polysiloxane-engineered cellulose foam with Ag/MnO2 schottky interfaces for synergistic adsorption-photocatalytic formaldehyde elimination.

Existing formaldehyde treatment systems are generally limited by the "adsorption-catalysis" interface kinetic barriers when coupling the dual functions of adsorption and photocatalysis. Pollutants captured at the adsorption sites tend to accumulate on the material surface due to the absence of a directional migration pathway, leading to the passivation of active sites. Simultaneously, catalytic sites suffer from low free radical utilization efficiency due to an insufficient supply of reactants, ultimately resulting in a vicious cycle of "adsorption saturation-catalysis stagnation". This study innovatively constructed an amino-functionalized grafted cellulose nanofiber/Ag-MnO2 ternary composite foam. Utilizing the three-dimensional network structure of hyperbranched polysiloxane, the material effectively exposed abundant amino active sites, enabling rapid formaldehyde adsorption under dark test conditions. It reached adsorption equilibrium within 50 min, achieving a maximum adsorption rate of 97.09 %. Under xenon lamp irradiation, the removal efficiency of formaldehyde reached a remarkable 99.55 %, and remained unchanged after 5 cycles. This material surpasses most others in removal speed, removal rate, and cyclic regeneration. Its unique "adsorption enrichment-interface migration-in situ degradation" dynamic mechanism overcomes the limitations of physical adsorption materials, which are prone to saturation and deactivation. This breakthrough offers a novel strategy for designing advanced indoor air purification materials.