Assessment of surface and electrical properties of the TiO2@zeolite hybrid materials

Abstract

Degradation of pollutants in aqueous medium is of high interest due to the impact on environment and human health, therefore, design and study of the physico-chemical properties of photocatalysts for water remediation are of major significance. Among properties of photocatalyst, those related to the surface and electrical mechanism are crucial to the photocatalyst´s performance. Here we report the chemical and morphological characteristics of TiO₂@zeolite photocatalyst by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) respectively, and a coherent electrical conduction mechanism was proposed based on data obtained from assisted laser impedance spectroscopy (ALIS), in which the zeolite was synthesized from recycled coal fly ash. The results obtained by SEM and XPS verified the presence of spherical particles of TiO₂ anatase with presence of Ti³⁺ state. ALIS results showed that impedance of the entire system increases when the amount of TiO₂ increases and the samples with lower capacitive performance allowed a larger transfer of the charges between the solid–liquid interface. All results showed that higher photocatalytic performance of TiO₂ growth over hydroxysodalite with 8.7 wt% and 25 wt% of TiO₂ can be explained in terms of the morphology of TiO₂ and the interactions between substrate-TiO₂ mainly.