Application Research On Electrochemical Nitrogen Reduction Based On Imitated Nitrogenase Catalyst

Ammonia is of great importance to modern human society and the natural world.The use of electrochemical synthesis of ammonia by renewable energy sources under environmental conditions,rather than using energy-intensive Haber-Bosch processes,is beneficial for the future development of sustainable societies.Therefore,the development of highly efficient catalysts with low overpotential and high selectivity is necessary,but still a formidable challenge.To address these challenges,we prepared the electrocatalyst by simulating the proportion of natural nitrogenase,and further used the photo-assisted technology to effectively improve the efficiency of ammonia synthesis:A three-dimensional graphene aerogel loaded with MoO₂and FeS₂nanoparticles(MoO₂/FeS₂/GA)was prepared by simulating Mo Fe nitrogenase.FeS₂is a kind of material with poor hydrogen evolution reactivity.Mo(?)can be used as the active center of nitrogen reduction,utilizing a 3D graphene aerogel as a substrate can prevent the aggregation of catalyst particles and maintain their stability.The as-obtained catalyst has excellent activity in the electrocatalytic NRR with an NH₃yield of 40.18?g h^-1mg^-1_cat.and faradaic efficiency as high as 37.44%at-0.25 V versus the reversible hydrogen electrode at environmental conditions using 0.1 M HCl electrolyte,compared with GA,FeS₂/GA,MoO₂/GA and other NRR electrocatalysts,this electrocatalyst has outstanding advantages in nitrogen fixation efficiency,especially in selectivity.Photo-assisted electrochemical nitrogen reduction can combine the advantages of photocatalysis and electrochemistry.It can not only produce ammonia under mild conditions,but also be powered by light.Subsequently,FeS₂is an excellent semiconductor material,it has optimal bandgap(0.95 eV),high absorption coefficient(?>10⁵cm^-1)as well as its high abundance and ecological friendness.Influenced by all these factors,the NRR photoelectrocatalytic performance of MoO₂/FeS₂/GA was investigated under the neutral condition(0.1 M Na₂SO₄)with the addition of infrared light source.The electrochemical results showed that MoO₂/FeS₂/GA catalyst achieves a high Faradaic efficiency of 5%and NH₃yield rate of 33.54?g h^-1mg^-1_cat.at-0.6 V vs.RHE.Compared with other neutral environment test experiments,the catalyst has a better ammonia production rate and excellent electrochemical stability.