Rapid And Scalable Production And Electrocatalytic Performance Of Bismuth Oxide Nanotube For CO₂ Reduction

Electrocatalytic CO₂ reduction powered by renewable energy can convert CO₂ into high value-added carbon-based fuel at room temperature and pressure,which is a promising carbon conversion technology.Until now,homogeneous and heterogeneous catalysts were developed successively for electrochemical reduction of CO₂.However,the large-scale application of most electrocatalysts is hindered by complex synthetic steps and low yield.Based on this,we propose a simple synthesis method to achieve the rapid mass production of Bi O₂-_x/Bi₂O₃,and investigate their performance for electrocatalytic CO₂ reduction.The main research contents are as follows::1.For the synthesis of Bi O₂-_x/Bi₂O₃ nanotube,firstly,a certain amount of Bi（NO₃）₃·5H₂O were dissolved in nitric acid aqueous solution.In addition,the obtained solution was reacted with alkaline reagents for only 1 min to obtain Bi O₂-_x/Bi₂O₃nanotube,which could be mass-produced by increasing the amount of reactants in equal proportion.Through X-ray diffraction（XRD）and X-ray photoelectron spectroscopy（XPS）,it was confirmed the target catalyst consists of Bi O₂-_x and Bi₂O₃,in which Bi₂O₃is the main component.From the transmission electron microscopy and high-resolution transmission electron microscopy images,it can be clearly seen that Bi O₂-_x/Bi₂O₃exhibits a unique morphology of nanotubes.2.The electrocatalytic CO₂ reduction performance of Bi O2-x/Bi2O3 was investigated.In the H-type cell,the pretreated Bi O₂-_x/Bi₂O₃ exhibited a faradaic efficiency for formate of higher than 90%over a wide range of applied potential from-0.9 to-1.4 V versus reversible hydrogen electrode（vs.RHE）.At-1.4 V vs.RHE,the partial current density for formate of Bi O₂-_x/Bi₂O₃ was-127 m A·cm^-2.Additionally,it showed favorable stability in 66 hours of electrolysis experiment The mechanism of Bi O₂-_x/Bi₂O₃ electrocatalytic CO₂ conversion to formate was further explored by CO₂adsorption isothermal curves and in situ Raman tests.Compared with commercial bismuth powder,this metallic bismuth obtained by in situ conversion of Bi O2-x/Bi2O3,which possesses superior CO₂ adsorption capacity and intrinsic activity,exhibited superior electrocatalytic CO₂ reduction activity.