Research On The Technology Of Melting Salt Electrochemical Transformation Of Carbon Dioxide To Prepare High Value-added Carbon Materials

The burning of fossil fuels has led to a sharp increase in the amount of CO₂ in the atmosphere,causing a serious greenhouse effect.Therefore,scientists from all over the world are encouraged to develop clean energy and explore low-carbon and environmentally friendly production technologies.It has already been noted that CO₂ is the most abundant C1 feedstock in nature.Sequestration and conversion technology to transform it into fuel and even chemical products is of great scientific interest as it can not only make full and efficient use of CO₂ resources but also reduce atmospheric CO₂ level the greenhouse effect.In recent years,high temperature molten salt electrochemical technology has attracted much attention in the field of CO₂ transformation,due to its advantages of fast reaction speed,high conductivity and wide electrochemical window.In this paper,molten carbonate was used as the high-temperature reaction medium and common,inexpensive metal material was used as the electrode material to regulate the key control factors such as electrolyte system,electrolytic temperature and current density to absorb CO₂ and synthesize valuable carbon materials.By means of scanning electron microscope（SEM）and X-ray diffractometer（XRD）technique,the morphology and structure of the products obtained by electrolysis in the lithium-containing electrolyte system,including unary,binary and ternary,were studied.Pure lithium carbonate electrolysis case under 750℃ produces carbon nanotubes with regular structure and radial diameter smaller than 100 nm.When the electrolytic temperature was gradiently increased,the product structure tend to bend and the radial diameter increased.Pure Li₂CO₃ case can control the electrolytic current to obtain carbon materials with various morphologies such as carbon spheres,amorphous carbon materials and carbon particles.The reduction reaction of metal oxides in molten salt electrolyte was regulated by gradient current electrolysis,and nanosized metal particles were formed on the cathode surface,which served as nucleation sites to catalyze the growth of carbon nanotubes.The indicated electrolyzer can not only absorb carbon dioxide,but also produce carbon nanotubes with great application potential,in line with the concept of sustainable development.