Preparation And Application Study Of The Molybdenum Disulfide Quantum Dots Modified Titanium Dioxide Nanorods Photoanode

Photoelectrochemical（PEC）technology,which uses semiconductor materials to convert light energy directly into chemical energy,is one of the effective ways to solve the energy problems and environmental issues faced in this century.Titanium dioxide（TiO₂）is an ideal semiconductor material because of its high chemical stability,non-toxicity and low cost,and its application in the field of photoelectrochemical detection and degradation of organic pollutants has good prospects.In this paper,titanium dioxide nanorods（TiO₂ NRs）thin film materials were prepared by hydrothermal method.A new all inorganic molybdenum disulfide quantum dots（MoS₂ QDs）modified titanium dioxide nanorods photoanode was designed and prepared for PEC detection of trace Pb²⁺in water and degradation of tetracycline hydrochloride.The main research results are as follows:（1）TiO₂ NRs thin film materials with excellent chemical properties were prepared by hydrothermal method.Under the optimized process（tetrabutyl titanate addition 0.5 ml,hydrothermal temperature 150℃,hydrothermal time 4 h,heat treatment temperature 450℃）,the photocurrent density in 1.0 M Na₂SO₄ solution is 1.23 m A/cm²@1.23 V vs.RHE.MoS₂ QDs were prepared by photo-deposition on the surface of TiO₂ NRs film.Under the optimized process（photo-deposition time 10 min,heat treatment temperature 250℃）,the photocurrent density in 1.0 M Na₂SO₄ solution was 1.66 m A/cm²@1.23 V vs.RHE.Since the conduction band bottom and valence band top of MoS₂ are higher than those of TiO₂,and they form p-n junction,it not only improves the absorption of visible light,but also effectively inhibits the recombination of carriers and improves the separation efficiency of carriers.（2）The PEC detection of trace Pb²⁺in water was realized by TiO₂NRs/MoS₂ QDs photoanode.In the process of TiO₂ NRs/MoS₂ QDs for trace Pb²⁺detection in water,the adsorption of Pb²⁺by MoS₂ can improve the visible light absorption and inhibit the carrier complexation,which improves the carrier separation efficiency and thus realizes the"signal on"strategy for Pb²⁺detection.Pb²⁺concentration ranges from 0 to 1000μM,the linear equations were y₁=0.0861+0.02966x₁（R²=0.9937）,y₂=0.00227+0.08019x₂（R²=0.9917）,and the detection limits were 0.0482μM,and the electrode exhibited good selectivity.（3）The deep degradation of tetracycline hydrochloride in water was realized by TiO₂ NRs/MoS₂ QDs photoanode.The PEC the reaction rate of degrading tetracycline hydrochloride was faster.The degradation efficiency of the solution containing tetracycline hydrochloride at a concentration of 5 mg/L and 70 ml for 90 min was 94.83%at a light intensity of 100 m W/cm²,an applied bias voltage of 0.6 V vs.SCE,and a solution p H of 6.1.The key active species for the degradation of tetracycline hydrochloride by TiO₂ NRs/MoS₂ QDs thin film materials were obtained from the active species burst experiments as h⁺and ·OH,and the catalytic activity of h⁺was greater than ·OH.