Theoretical Design And Calculation Of Novel Two-dimensional Materials For Electrocatalytic Nitric Oxide Reduction

Ammonia is a very important chemical raw material in modern industrial and agricultural production,but the current ammonia production process will cause a large amount of energy consumption and serious environmental problems,the development of efficient electrocatalyst to convert nitrogen into ammonia is a major chemical chalenge,is of great significance to maintain life.In the electroreduction of nitrate and nitrite,nitric oxide(NO)is considered as a key intermediate which determines the product selectivity and affects the overall reaction rate.In addition,NO emission control is also an important issue in the nitrogen cycle.Therefore,it is of great significance to study the electrochemical reduction(NOER)of NO and to search for efficient NOER electrocatalyst with high activity and selectivity for the sustainable production of ammonia(NH₃).Therefore,this paper attempts to design and simulate NOER electrocatalyst,and mainly carries out the following two tasks:1.In this paper,two b-doped molybdenum sulfide selenide(Mo SSe)catalysts were designed,and the NOER reactivity of NO molecule on the surface of the two catalysts was investigated.We first analyzed the adsorption capacity of NO molecule on the surface of the two catalysts,and found that the adsorption effect of NO on the two catalysts was roughly the same.Then,according to the calculation of Gibbs free energy,the internal mechanism of synthesizing NH₃ by electrocatalytic reduction of NO was further revealed.The results showed that*HNO was the key intermediate in the reaction process which possess the lowest limiting potential.We also explored the kinetics of all the basic steps of NOER on the catalyst surface,and found that the optimal reaction path is NO?*NO?*HNO?*HNOH?*NH?*NH₂?*NH₃.At the same time,we also explored the influence of changing stress on the key intermediates and the minimum limiting potential,and find that changing stress can change the value of the minimum limiting potential.But it can not change the key intermediates and the optimal reaction path.Finally,we proves that both catalysts can inhibit hydrogen adsorption and are more inclined to NOER reaction by comparing between HER and NOER.2.In this paper,the NORR catalytic activity of transition metal atoms(TM=Fe,Co,Ni and Cu)which was fixed on the g-C₆N₆ monolayer has been studied by first-principles calculations.We first analyzed the adsorption capacity of NO molecule on the surface of the four kinds of catalysts,and then explored the kinetics of all the basic steps of NOER on the catalyst surface.The results show that*HNO is the key intermediate in the reaction process,which is the same as the calculation results in the previous part.At the same time,it was found that the catalyst doped with Cu atoms on g-C₆N₆ could fully activate nitric oxide molecules and effectively reduce nitric oxide to ammonia with low limiting potential,while the other three kinds of catalysts had relatively high limiting potential.Then,through the analysis of the stability,activity and selectivity of the four catalysts,Cu@g-C₆N₆ monolayer is selected as the most promising NOER candidate material.Finally,NOER on Cu@g-C₆N₆ is compared with hydrogen evolution reaction,which proves that Cu@g-C₆N₆ catalyst has better NORR selectivity.