CuS nanoparticles decorated MoS2 sheets as an efficient nanozyme for selective detection and photocatalytic degradation of hydroquinone in water

Abstract

The development of cost effective and efficient nanomaterials with enzyme mimetics and photocatalytic activity has achieved tremendous research interest in the quantitative detection as well as removal of toxic environmental pollutants. CuS nanoparticles decorated MoS₂ sheets were successfully synthesized adopting a simple hydrothermal technique and using low-cost materials. The nanocomposite was successfully used as an efficient catalyst for the selective detection and removal of a toxic phenolic compound like hydroquinone (HQ). The CuS–MoS₂ nanocomposite catalyzed the oxidation of different chromogenic substrates like 3,3′,5,5′-tetramethylbenzidine, 2,2′-azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid)diammonium salt, and o-phenylenediamine in the presence of H₂O₂, indicating its peroxidase-like activity as natural Horseradish peroxidase (HRP). The catalytic performance of the nanozyme was further investigated through the typical Michaelis−Menten kinetics. The results showed that the proposed sensor exhibited improved catalytic properties with a wide linear relationship (0.4–50 μM) and a low detection limit of 3.68 μM for HQ detection in aqueous medium. Meanwhile, the mechanism of HQ sensing in the presence of CuS–MoS₂ nanozyme was systematically investigated. Moreover, the CuS–MoS₂ nanozyme possessed significant photocatalytic activity and 83% HQ decomposition was achieved within 240 min under irradiation of natural sunlight. The mechanism of enhanced photocatalytic degradation of HQ through the formation of ˙OH radicals as reactive species was evidenced by analyzing the formation of fluorescent active molecules on the addition of terephthalic acid and by high-resolution mass spectrometry. Thus CuS–MoS₂ represents a new and promising HQ sensing material in a highly sensitive and fast manner as well as an efficient photocatalyst for the degradation of HQ to its non-toxic products under natural sunlight irradiation.