自清洁半导体异质结衬底

Abstract

Emerging technoloqies in the feld of environmental remediation are becoming increasinaly sianifcant owing to theincreasing demand for eliminating signifcant amounts of pollution in water, soil, and air. We designed andsynthesized MoS,/Fe,0; heterojunction nanocomposites (NCs) as multifunctional materials that are easily separatedand reused, The trace detection performance of the prepared sample was examined using bisphenol A (BPA) as theprobe molecule, with limits of detection as low as 10-9 M; this detection limit is the lowest among all reportedsemiconductor substrates. BPA was subiected to rapid photocatalytic degradation by MoS,/Fe,0, NCs underultraviolet iradiation. The highly recyclable Mos,/Fe,0, NCs exhibited photo-Fenton cataltic activity for BPA andgood detection ability when reused as a surface-enhanced Raman scattering (SERS) substrate after catalysis. The SERsand photocatalysis mechanisms were proposed while considering the effects of the Z-scheme charae-transfer pathsthree-dimensional flower-ike structures, and dipole-dipole coupling. Moreover, the prepared MoS,/Fe,0, NCs weresuccessfullv applied in the detection of BPA in real lake water and milk samples. Herein, we present insights into thedevelopment of MoS,/Fe,0, materials, which can be used as multifunctional materials in chemical sensors and inphotocatalytic wastewater treatments for the removal of recalcitrant organic pollutants.

Introduction

Serious environmental pollution and accelerated globalwarming are attributed to the rapid consumption of fossilfuels, the increasing population, and the rapid developmentof the economy. Thus, the development of innovativeand renewable environmental remediation materials isbecoming increasingly important'-6.Since mechanicallyexfoliated graphene was discovered, the development of two-dimensional (2D) materials consisting of atomicallythin crystal layers bound by van der Waals forces hasaccelerated owing to the potential applications of thesematerials in optoelectronics, catalysis, new technologiesand electricity?-9..2D-MoS, nanosheets are excellentlayered materials, having unique layered structures andlarge surface areas. It is important to investigate methodsfor improving the chemical properties of MoS, which mayaffect its application in electronic devices, catalysis, and0. A popular method for improving themolecular sensingproperties of MoS, is the decoration of MoS, with noblemetal nanoparticles. For instance, a MoS,/noble metalnanoparticle composite can induce local surface plasmonresonance (LSPR) for activating the photoelectrocatalysis ofH, and enhancing the light absorption or emission of MoS,. Moreover, the LSPR can generate surface-enhancedRaman scattering (SERS), which can be used in biologicaland chemical sensing applications!1-13.Among varioustraditional noble metal materials, Au nanomaterials are themost widely used SERS substrate material14-16, However,the high cost and specialized instruments required for Ausubstrates hinder their practical application. Due to its veryhigh SERS activity, Ag is another widely studied substratematerial17. Although the price of Ag is much lower than theprice of Au, the main defect of Ag is its poor stability,which easily oxidizes in air. To address these problems, it isessential to exploit synergistic effects by incorporatinginexpensive and stable semiconductors.

Thus far, a few MoS,-based heterostructures, such asCdS/MoS_, TiO2/MoS2, and MoO3/MoS, have exhibitedhigher photocatalytic efficiencies than pristine MoS,18-20Investigations have been continuously conducted on theefficient separation of a nanocomposite (NC) from atreated effluent, along with the subsequent reusability ofthe NC. Several research groups have begun to focus onmagnetically separable photocatalysts for wastewatertreatment, demonstrating the value of the special prop-erties ofmagnetic materials. Among these magneticmaterials, Fe O3 has a narrow bandgap, high chemicalresistance, and high resistance to corrosion. Therefore,rationally designed MoS,/Fe,O3 NCs can serve as a reu-sable SERS substrate for detection and easily reclaimedphotocatalyst. The recovery andeconomical reuseMoS,/Fe,O3 NCs photocatalysts is easily achieved byadding an external magnetic field.

Bisphenol A (BPA) is believed to be an endocrine disruptorand widely exists in food containers and the environmentEven low levels of BPA entering the body can disrupt theendocrine system by binding to estrogen receptors, whichmay lead to cardiovascular diseases, immune function defi.ciencies, impaired reproductive capacity, and other diseases21-.23, Thus, it is imperative to develop a facile, rapid, andinexpensive method for BPA detection and degradation.

In this study, MoS/Fe,O3 NCs were prepared via asimple low-temperature hydrothermal method, and theadvantages of the two materials were combined. Forexample, after 50 min of ultraviolet (uV) irradiation, thesubstrate completely degraded BPA, and upon recovery,demonstrated its detection capability. Compared withMoS, NFs and Fe2O3 NPs, the rate of degradation of BPAand the SERS activity of MoS,/Fe2O3 NCs were sig-nificantly better. This new, easily recoverable SERS sensorwith a high sensitivity will facilitate sensing harmfulmolecules. To the best of our knowledge, no MoS,/Fe2O3composites that exhibit BPA detection and photocatalysismultifunctionality have been reported thus far. Photocatalytic and SERS mechanisms were also proposed.