Preparation Of Molybdenum Disulfide Composite Catalysts For Photocatalytic Reduction Of CO₂

Global warming and energy shortages are the top issues we face in the 21st century.Carbon dioxide?CO₂?is the end product of fuel combustion.It is an important greenhouse gas that produces carbohydrates through natural photosynthesis.This process is essential to maintain the balance of the ecosystem.With the deep understanding of photosynthesis,photocatalytic reduction of CO₂ into organic fuel by artificial simulation of sunlight has been successfully realized.This reaction process reduce the greenhouse gas emissions and realize the carbon cycle and have effectively solved the energy shortage problem,it is particularly important to study the preparation of photocatalysts that convert carbon dioxide into organic fuels.This paper mainly studies the reduction of CO₂ to methanol by photocatalysis in an isopropanol system.The experiment will investigate the optimal conditions for the preparation and reaction of several photocatalysts,and evaluate the performance of photocatalytic reduction of CO₂.The main research contents include:1.The 3D-flower MoS₂ was prepared by hydrothermal method,and the MoS₂ with larger specific surface area and thinner layer was obtained by lithium ion intercalation.In order to find an optimum photoabsorption performance of MoS₂,the experiment mainly considered the effects of sulfur source,crystallization temperature,crystallization time.The optimized preparation conditions:thiourea as the sulfur source,hydrotherm temperature 200°C,crystallization time 24 h;under the action of n-butyl lithium intercalation and ultrasonic treatment for 3 h,MoS₂ with the largest specific surface area was prepared.Due to n-butyl lithium intercalation,MoS₂ becomes an unstable 1T structure,the experiment realize the transformation of MoS₂ from 1T to 2H by means of wet chemical method in nitrogen protection.2.The Ag nano-particles were loaded onto MoS₂ by reduction method,and the Ag/MoS₂composite catalyst was successfully prepared.The experiment study on influence of MoS₂ on photocatalytic reduction of CO₂ under different loadings of Ag.The experimental results show that the composite catalyst with 20wt%Ag/2H-MoS₂ has the best photocatalytic activity,and the yield of methanol is 365.08?mol/g/h.3.The In₂O₃/MoS₂-Gr ternary composite catalyst was successfully prepared by hydrothermal method.The experiment study on influence of In₂O₃/MoS₂ on photocatalytic reduction of CO₂ under different loadings.Based on the optimal activity of In₂O₃/MoS₂composite catalyst,the experiment study on influence of graphite on photocatalytic reduction of CO₂ under different loadings for preparing methanol.The experimental results show that the15wt%In₂O₃/MoS₂ composite photocatalyst has the best activity,and the methanol yield up to680.46?mol/g/h.On this basis,different amounts of graphite were loaded,and it was found that the loading of graphite as 30%,the methanol yield can up to 1100.42?mol/g/h.Therefore,the In₂O₃/MoS₂-Gr has better photocatalytic activity than In₂O₃/MoS₂.4.In this experiment,the semiconductor energy band and Mott–Schottky spectrum were obtained by using Material Studio?MS?simulation software and electrochemical workstation,we explore and validate the mechanism of photocatalytic reduction of CO₂ using In₂O₃/MoS₂-Gr in isopropanol.