Photocatalytic Hydrogen Production From Antibiotic Wastewater On Sulfide Composite System Loaded With MoS₂ As Co-catalys

With the rapid development of society,energy and environmental issues have become urgent issues for human sustainable development.Photocatalytic technology has important application prospects in the field of energy and environment because of its green and environmental protection.Among them,photocatalytic hydrogen production technology can convert solar energy into hydrogen energy in one step,which is an ideal method to solve energy and environmental problem.Cadmium sulfide（CdS）,as a material with a narrow band gap and suitable band position,was widely used in photocatalytic hydrogen production and photocatalytic degradation of pollutants.However,the photocatalytic activity of a single CdS material is low due to the rapid recombination of photogenerated carriers and low re-dox capacity.Molybdenum disulfide（MoS₂）is a low-cost photocatalytic hydrogen production material with excellent performance,was often used as co-catalyst of the CdS system to improve its photocatalytic hydrogen production activity.MoS₂ has different crystal phases,such as metal phase（1T-MoS₂）and semiconductor phase（2H-MoS₂）,and different crystal phases have different catalytic activities.Zn S has a similar crystal structure and atomic radius to CdS,and is usually used to form Zn_xCd_1-xS solid solution to adjust the energy band structure of CdS.This study explored the effects of MoS₂ loading and Zn_xCd_1-xS solid solution formation on the photocatalytic hydrogen production activity and pollutant degradation performance of CdS-based photocatalysts under visible light.In this paper,MoS₂@CdS nanosheet-nanosphere catalyst and MoS₂@Zn_xCd_1-xS polyhedron photocatalyst were synthesized by one-pot hydrothermal method.The hydrogen production performance and degradation rate of antibiotic wastewater of the catalyst were tested in0.1g/L amoxicillin aqueous solution under visible light（λ>420 nm）.The phase structure,micro-morphology,element composition,surface valence bond,optical characteristics,photoelectrochemical characteristics of the catalyst were analyzed by XRD,SEM,HRTEM,HADDF,XPS,Raman,UV-vis DRS,EIS,I-t,PL,TRPL and other characterization methods.And the photocatalytic degradation path of antibiotic wastewater was proposed by HPLC-MS characterization results.In the MoS₂@CdS photocatalyst synthesized by one-pot hydrothermal method,XPS and Raman spectra show that MoS₂ was in a mixed state of 1T and 2H,and there was a strong interaction between CdS and mixed phase MoS₂.This strong interaction will promote charge separation and thus improved hydrogen production performance.Moreover,the load of MoS₂will make the absorption band of CdS red-shifted.Among them,the5%MoS₂@CdS sample had the highest photocatalytic hydrogen production efficiency,reaching 87.0μmol/h under visible light,and the degradation ratio of amoxicillin antibiotic wastewater was 16.4%within 6 hours.In order to further explore the possibility of improving the photocatalytic performance,MoS₂@Zn_xCd_1-xS photocatalyst was synthesized by adding Zn（CH₃COO）₂·2H₂O.The experimental results confirmed the formation of Zn_xCd_1-xS solid solution.MoS₂ was also a mixed phase and formed a strong interaction with Zn_xCd_1-xS solid solution.PL and TRPL characterization shown that the loading of MoS₂ co-catalyst can promote the migration of photo-generated electrons inside the catalyst and prolong the life of photo-generated carriers.MoS₂ cocatalyst loading and Zn/Cd ratio both have a great influence on the hydrogen production performance of the sample,of which the 8%MoS₂@Zn_0.5Cd_0.5S sample has the best hydrogen production performance,reaching 128.0μmol/h under visible light,and the degradation ratio of amoxicillin antibiotic wastewater was 28.7%within 5 hours.