Tailoring the surface topography and crystallinity of Au0 sensitized ZnO Schottky heterojunction for enhanced photocatalytic degradation of tetracycline

Abstract

Background

The release of antibiotics into the soil and aquatic ecosystem has become the main concern leading to significant ecological imbalance and adversely affect human health. Unlike other pollutants, antibiotics are designed in such a way with good stability to treat human diseases. Even though it has several advantages, the prolonged existence and resistance to breakdown in environmental settings is a major concern.

Methods

In this work, Au⁰ sensitized ZnO Schottky heterojunction was engineered for the enhanced photocatalytic degradation of tetracycline (TC) under visible light irradiation. Here, ZnO was synthesized by simple co-precipitation method and the incorporation of Au onto the ZnO was performed via a double boiling-assisted reflow method.

Significant findings

The crystalline structure of Au@ZnO yolk in shell (AZYIS) was validated by XRD analysis and the HR-TEM imaging. The other characteristic properties such as structural, optical properties, etc., were demonstrated by SEM, UV–Vis DRS, XPS, EIS, PL and BET analysis. Here, ATYIS outperformed than pristine ZnO by achieving higher degradation rate of TC. The performance of the nanomaterial after six cycles were almost identical to the first cycle of degradation. The degradation of TC was enhanced by the participation of photogenerated radical species. The degradation pathway and the toxicity of the intermediates were analyzed using GCMS/MS analysis and ECOSAR, respectively. Further, the work conducted on AZYIS signifies that the unique design and the Schottky heterojunction significantly enhanced the stability, performance and reusability for sustainable wastewater remediation.