Derivatives of Br-doped metal-organic framework for improved acetaldehyde adsorption-photocatalytic oxidation

Different Br-doped metal-organic frameworks (MOFs) derived (Br_x@UiO-66) have been prepared by heat treatment using UiO-66 as the precursor. The experimental results showed that Br_0.2@UiO-66 exhibited the best photocatalytic oxidation and adsorption performances toward acetaldehyde. In the dynamic system, the acetaldehyde removal rate and adsorption capacity of Br_0.2@UiO-66 were 93.2 % and 230.59 mg/g, respectively. The improvement of the photocatalytic performance can be attributed to the presence of Br ions and CBr bonds, which facilitated the rapid separation of electrons and holes and the production of •O₂^-. In addition, Br_0.2@UiO-66 had a better adsorption performance than 300UiO-66, mainly because of the increased Lewis acidity of the metal active sites due to Br doping. Radical capture experiments indicated that •O₂^- and e^- were the primary active substances in acetaldehyde oxidation, and allowed establishing the possible mechanism of acetaldehyde oxidation. This work shows that MOFs can have high catalytic oxidation performances toward volatile organic compounds (VOCs) while retaining their adsorption capacity, and can be used for practical applications in the adsorption-catalytic integrated degradation of VOCs.