Preparation Of Ti/MoS₂-Ce/GO Electrode、 Hydrogen Production And Electrocatalytic Reduction Of CO₂

"Carbon peaking"and"Carbon neutrality"and the achievement of the utilization of carbon dioxide（CO₂）is the current research hotspot.The conversion of CO₂ into high value-added chemical products（such as methane,formic acid,etc.）by electrochemical reduction method provides an effective way to reduce CO₂ emission.The key of the electrochemical reduction of CO₂ lies in the existence of reductant hydrogen（H₂）.Hydrogen production by efficient and clean electrolytic water has great prospects,but its high-cost requires the development of a low-cost and efficient catalyst.Molybdenum disulfide（MoS₂）is an excellent catalyst for hydrogen production due to its abundant reserves,low-cost and large number of active sites.However,MoS₂ is easy to agglomerate,the active site can not be sufficient exposed and the conductivity is poor,which affects the hydrogen production efficiency.In this study,the catalytic performance of MoS₂ was improved by activating the inert basal plane of MoS₂ by doping,and enhancing its conductivity by coupling with the conductive base.The specific research results are as follows:Firstly,Ti/MoS₂-Ce/GO electrode with sandwich structure can be used as hydrogen evolution catalyst due to its high base surface activity and good conductivity.Ti/MoS₂-Ce/GO electrode has been prepared by a two-pot hydrothermal method.Firstly,the rare earth element cerium was added into the lattice of MoS₂ to activate the inert basal plane.Secondly,GO is loaded onto the surface of MoS₂-Ce to accelerate the electron conduction rate.The Ti/MoS₂-Ce/GO electrode exhibited a low overpotential of 120 m V at 10 m A/cm² in acidic solution with corresponding Tafel slope of 53 m V/dec.The electrochemically active surface area is 432.5 m F/cm²,and the charge transfer resistance is 3.25Ω.After 3000 potential cycles,the Ti/MoS₂-Ce/GO electrode had only minor changes in activity and exhibited long-term stability of over 20 h.The electrode has excellent stability in both acidic and alkaline solutions.Secondly,the effects of voltage,electrolyte concentration,electrolyte temperature and electrolytic time on hydrogen production by electrolytic water were investigated.The effect of various factors on hydrogen production by Ti/MoS₂-Ce/GO electrode was investigated by single factor experiment.The result showed that voltage,electrolyte concentration and electrolyte temperature had great influence on electrolytic water hydrogen production.Then,with the hydrogen production rate as the response value,the optimal reaction conditio was achieved through the response surface optimization experiment:The voltage was 6.5 V,the electrolyte concentration was 0.75 mol/L,and the electrolyte temperature was 45℃.The predicted hydrogen production rate was 17.30 mmol/（cm²·h）,and the95%confidence interval was 8.78～25.82 mmol/（cm²·h）.The experimental results showed that the hydrogen production rate was 15.38 mmol/（cm²·h）,which was within 95%confidence interval.Finally,the long-term performance test and SEM and XRD analysis of the electrode showed that the electrode has good stability and can achieve high efficiency hydrogen production in the cathode.Finally,Ti/MoS₂-Ce/GO electrode was used in CO₂ reduction reaction.In H-type electrolytic cell,the Faraday efficiency of formic acid production(FE_HCOOH)of Ti/MoS₂-Ce/GO electrode at-1.3 V（vs.RHE）is 13.04%.Under the optimal electrolytic potential,the effects of pH value,CO₂ flow rate and other factors on CO₂ reduction by electrode were further explored.It was found that the formic acid production efficiency was 24.22%when pH was 8.8 and CO₂ flow rate was 35 m L/min.During the 12-hour CO₂reduction experiment,Ti/MoS₂-Ce/GO electrode still keeps the current density relatively stable,which showed high catalytic stability.Finally,the mechanism of electrocatalytic reduction of CO₂ was analyzed.In this study,the Ti/MoS₂-Ce/GO electrode has high catalytic activity,good conductivity and excellent stability,and can achieve high efficiency electrolytic water hydrogen production and CO₂ reduction,contributing to the achievement of the"double carbon"goal.