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.