Adsorption And Electrocatalytic Reduction Of CO₂ On Phthalocyanine Carbon Based Nanoporous Electrodes

Electrocatalytic CO₂ reduction technology can capture the chemical bonds of intermittent renewable energy sources,thus enabling traditional fossil fuel-based conversion to renewable energy sources as electricity,and converting waste CO₂ into products with certain value,for future carbon neutral production certain positive effect.The difference between electrocatalysis and traditional methods is that it can control the selectivity of products,which can be done at normal temperature and pressure,consumes water and carbon dioxide in the reaction,generates valuable energy products,and can achieve sustainable cycles.The electrocatalytic CO₂reduction device is relatively simple,the experimental operation is convenient,and it has a promising application in industrial production.In this paper,phthalocyanine materials were used as the main raw material for the preparation of stable and Faraday efficient carbon-based nanoporous electrodes to prepare the reduction product methanol.The relevant studies are as follows:firstly,the possibility of catalytic reduction of CO₂ by phthalocyanine materials was verified using a coating method with cobalt and copper phthalocyanine as the main raw materials.The corresponding discussions were carried out with cyclic voltammetry,linear cyclic voltammetry,stability measurements and electrochemical impedance to compare the advantages and disadvantages of the phthalocyanine materials.It was found that the copper phthalocyanine gradually lost stability after 0.5h compared to the cobalt phthalocyanine material and that the cobalt phthalocyanine was not as selective in producing methanol（FE=3%）.Subsequently the cobalt phthalocyanine and the carbon nanotube-doped cobalt phthalocyanine material were drop-coated by ultrasonic mixing method.It was found that both the cobalt phthalocyanine material and the cobalt phthalocyanine material doped with carbon nanotubes had good stability,and the selectivity of the methanol production from the cobalt phthalocyanine catalyst doped with carbon nanotubes material was further improved（FE=10%）.Finally,in order to improve the selectivity of the liquid product methanol,the cobalt phthalocyanine and carbon nanotubes material were treated with ball milling technique to further improve the dispersion of the material,and it was found that this method highest selectivity（FE=16%）for the production of methanol and excellent stability.It was shown that the catalytic performance of cobalt phthalocyanine under the same preparation conditions was better than that of copper phthalocyanine.The addition of carbon nanotubes improves the electrical conductivity of the phthalocyanine material and increases the reduction current density.The behaviour of the cobalt phthalocyanine material in the reduction of CO₂ to methanol is related to the dispersion effect of the material,and the lower reduction potential is beneficial to inhibit the production of methane products.The addition of a certain amount of carbon nanotubes is beneficial to inhibit the generation of side reactions.