Effect of ligand substitution in UiO-66 metal-organic frameworks on the photocatalytic oxidation of acetaldehyde

A series of functionalized X-UiO-66 (X = NH2, H, Br and NO2) materials were prepared using a hydrothermal method and modified with various ligands. Their photocatalytic activity was evaluated by the oxidation of acetaldehyde. Experimental results show that the introduction of different ligands significantly influences the physicochemical properties of UiO-66. Br-UiO-66 exhibited the highest photocatalytic activity and CO2 selectivity of 85.6% and 85.7%, respectively. Photochemical properties reveal that -Br functional group facilitate the separation of photogenerated electrons and holes, significantly improving their transfer and oxygen reduction. As a result, an increased number of hydroxyl and superoxide radicals can form, improving the efficiency of the photocatalytic reaction. Br-UiO-66 accumulates fewer intermediates on its surface and still shows excellent photocatalytic activity and structural stability after 24 h of dynamic reaction. This work demonstrates the excellent adsorption and catalytic oxidation performance of Br-UiO-66 towards acetaldehyde and may provide new ideas for researching catalysts in the photocatalytic degradation of pollutants.