Preparation Of Antimony Nanosheets And Antimony Oxide Nanorods And Their Performance For Electrocatalytic Nitrogen Fixation

Ammonia（NH₃）is one of the most basic chemical raw materials in industrial and agricultural production.It is mainly prepared by the traditional Haber-Bosch process,which has high energy consumption and serious pollution.At present,nitrogen and water are used as raw materials to synthesize ammonia by electrocatalytic nitrogen reduction reaction（NRR）under ambient conditions.Because of the availability of raw materials and mild reaction conditions,it is expected to become a sustainable green ammonia synthesis technology in the future.However,since the N≡N bond in N₂ is strong,it is difficult to activate under ambient conditions.At the same time,the electrocatalytic nitrogen reduction in aqueous solution is accompanied by a strong hydrogen evolution competitive reaction,which seriously restricts the efficiency of electrocatalytic nitrogen reduction.Therefore,the development of a highly active and selective nitrogen reduction catalyst is the key to electrochemical synthesis of ammonia under ambient conditions.Due to the lack of effective electrocatalysts,electrocatalytic nitrogen fixation as a green and sustainable technology is far from practical.In this paper,antimony nanosheets and antimony oxide nanorod were prepared by simple chemical methods,and their chemical structures were adjusted and used for electrocatalytic nitrogen reduction reactions.The main research contents and conclusions are as follows:（1）Porous antimony nanosheets with high selectivity for electrocatalytic nitrogen fixation were prepared by a simple chemical stripping method,and their performance and stability in electrocatalytic nitrogen fixation were studied.The results show that the preparation method simultaneously achieves high-efficiency large-scale exfoliation and formation of porous structures,increasing the specific surface area and the number of catalytically active sites,and easily adsorbs N₂ and weakens the N≡N bond.The porous structure also had a significant effect on the improvement of nitrogen fixation activity,achieving a higher average NH₃ yield and Faraday efficiency at-0.7 V（vs.RHE）,up to 2.08μg h^-1 cm^-2 and 14.25%.At the same time,the material’s potential determination step（PDS）free energy change（ΔG）is low,and the interaction between*NNH and the ruthenium surface is stronger.In addition,cerium nanosheets not only have high electrocatalytic nitrogen fixation activity,but also have good electrocatalytic stability.（2）Antimony oxide nanorod materials were prepared at different calcining temperatures.Compared with commercial antimony oxide,antimony oxide nanorods have a lower overpotential and a higher current density at the same potential.Sulfur is doped into the antimony oxide nanorod lattice with less content during the synthesis process,which can improve the conductivity of the antimony oxide nanorods,introduce defects,and improve the reaction activity.At the same time,lower internal resistance and low crystallinity result in faster electron transfer rate and lower charge transfer resistance,which show better electrochemical performance.Among them,the antimony oxide nanorod material calcined at300°C can produce ammonia at a rate of 6.88μg h^-1 cm^-2 at-0.18 V（vs.RHE）,and its corresponding Faraday efficiency can reach to 32.5%.Moreover,the formation of hydrazine as a by-product was not detected during the experiment,confirming the excellent selectivity and catalytic activity of antimony oxide nanorods for nitrogen reduction.At the same time,it shows good stability in the electrochemical cycle test.（3）Compared with antimony nanosheets,the antimony oxide nanorods prepared in this paper have better nitrogen fixation effect in terms of electrocatalytic nitrogen fixation performance,and the antimony nanosheets have higher stability.The preparation steps of the antimony nanosheets are simpler and more environmentally friendly,and the antimony oxide nanorods have a higher yield.