Novel Zn/MoSe2 nanoflower with selenium vacancies for the effective charge separation, photo-electrochemical study and efficient visible-light degradation of Ciprofloxacin

Abstract

This research investigated the effectiveness of the novel selenium vacancy (2.5%, 5%, 7.5% & 10%) within the nano-flower structure of Zn/MoSe₂, synthesized through the hydrothermal method, as a photocatalyst for degrading Ciprofloxacin (CIP) under visible light exposure. CIP has been broken down in an appropriate photocatalytic reactor, and the reaction rate constant has been assessed. After 45 min exposure, optimized selenium vacancy i.e., 5% Zn/MoSe₂ shows highest photocatalytic degradation of 98.68% in CIP based waste-water. The remarkable photocatalytic activity can be ascribed to the creation of a selenium vacancy that impedes the recombination of holes and electrons. The vacancies can be created with greater ease by using amalgamation of metals possessing distinct electronegativities. The optimised photocatalyst showing a very good stability which has been checked through recycle test and post-reaction characterisation. The study utilized RSM modeling, notably employing the Box-Behnken design, to ascertain the most favourable operational parameters for the visible-light degradation. The parameters encompass solution pH, catalyst dose, and initial CIP concentration. The 5% Zn/MoSe₂ demonstrated significant degradation efficiency, achieving degradation percentage of 90.76% in tap water and 86.15% in lake water. Superoxide radicals which are mainly responsible for degrading CIP have been tested using scavenging experiments, TMPD and EPR tests. Transition products were found using LC-MS, and their existence was then utilised to suggest a degradation pathway.