The regulation of Lewis acid/basic sites in NaFe bimetal MOXs for the controllable photocatalytic degradation of electron-rich/deficient VOCs

The performance of metal-organic xerogels (MOXs) in the photocatalytic oxidative degradation (PCO) of volatile organic compounds (VOCs) relies on their Lewis acid-base interaction and the generation of oxidative radicals. Herein, by engineering the local charge imbalance of carboxyl ligands through synthesizing NaFe bimetal MOXs, the Lewis acidity of MIL-100(Fe) MOX was well tuned for the adsorption-degradation of electron-rich (aromatic hydrocarbons) and electron-deficient (aldehydes) VOCs. Benefiting from the implanted Lewis basic sites, NaFe-MOXs showed increased adsorption-PCO capacity for single acetaldehyde, while Fe-MOX with abundant Lewis acid sites could capture and degrade more o-xylene. The Lewis basic sites promoted the mineralization of single o-xylene and acetaldehyde by altering their interactions with the photocatalysts and improving the generation of oxidative radicals, which extended the lifetime of photocatalysts. By regulating the Lewis acid/basic sites within MOXs, this work provides an effective way for optimizing photocatalysts to enable the photocatalytic degradation of both electron-rich/deficient VOCs.