Effect of SiO2 aerogels loading on photocatalytic degradation of nitrobenzene using composites with tetrapod-like ZnO

Abstract

To study the effect of improved adsorption property of tetrapod-like ZnO (T-ZnO) on its photocatalytic performance, a new composite was prepared by loading silica aerogels (SiO2(AG)) on the surface of T-ZnO via the sol–gel method. Various characterization methods showed that SiO2(AG) was uniformly loaded on the surface of T-ZnO, and the morphology as well as structural characteristics of SiO2(AG) and T-ZnO were not changed. Nitrobenzene (NB) was selected as the model pollutant, and the adsorption and photocatalytic properties of T-ZnO and SiO2(AG)/T-ZnO for NB were studied. The photocatalytic degradation processes of NB using T-ZnO and SiO2(AG)/T-ZnO followed the first-order reaction. Considering the initial moment reaction kinetic, the photocatalytic kinetic of SiO2(AG)/T-ZnO and T-ZnO was consistent with the Langmuir–Hinshelwood kinetic model, and reaction rate constant kSiO2AG/T-ZnO′>kT-ZnO′{k}_{{\text{SiO}}_{2}\left(\text{AG}\right)/\text{T-ZnO}}^{^{\prime} }\gt {k}_{\text{T-ZnO}}^{^{\prime} }, adsorption rate constant KadSiO2(AG)/T-ZnO{K}_{\text{ad}{\text{SiO}}_{2}(\text{AG})/\text{T-ZnO}} > K ad T-ZnO, which demonstrated that SiO2(AG) loading could increase T-ZnO adsorption to NB, then promoted its photocatalytic performance.

Keywords

• silica aerogels
• tetrapod-like zinc oxide
• adsorption property
• photocatalytic performance
• nitrobenzene