The Research Of Anti-perovskite Nitrides Applied In Electrocatalysis

With the increasing serious energy crisis and environmental pollution problems,electrochemical energy storage and conversion systems such as electrolyzed water devices and rechargeable metal-air batteries are regarded as the key choice to ease these problems due to their renewable and pollution-free advantages.Electrocatalyst is the key factor for reducing the reaction activated energy and increasing the energy conversion efficiency in the above mentiaoned systems.Therefore,the development of high-efficient electrocatalyst plays an important role in the popularization of these electrochemical devices on the practical application.Nowadays,although precious metal catalysts such as Pt/C and Ir/C exhibit excellent catalytic activity,the high cost and scarcity make them difficult to go through large-scale process.Thus,it is essential to find non-noble metal catalysts.Among them,metal oxides stand out by their cost-effective,but they have suffered from poor conductivity which need to employ carbon material to improve the conductivity.However,the sharp deterioration of the electrocatalytic activity by the corrosion of carbon materials under high-potential environments has greatly limited their use in the field of electrocatalysis.Unlike metal oxides,transition metal nitrides exhibit dersiable conductivity and have been widely studied in the electrocatalysis recently.Among the transition metal nitrides,there is a type of nitrides called anti-perovskite nitride with a formula of ANM₃,which has been used as the superconductor materials due to their excellent conductivity and unique electronic configuration.The promising conductivity of the antiperovskite nitrides can ensure the fast transfer of the eletron during the electrocatalytic process.In addition,the compositional flexibility of this nitride can enable the optimization of their electronic configuration to improve the electrocatalytic performance,which makes them an ideal material for eletrocatalysts.However,previous studies on these anti-perovskite nitrides mainly focus on the basic physical research,while their applications toward electrocatalysis have rarely been explored.Herein,this thesis carried out the research on the development of the antiperovskite nitrides electrocatalyst with high efficiency and their application in energy conversion and storage system by adjusting their composition.Firstly,a series of Mn-doped anti-perovskite nitrides In NCo_3-xMn_x were synthesized by hydrothermal method.Electrochemical measurements were adopted to explore the effects of different Mn doping amounts on oxygen evolution reaction?OER?activity.It was found that only appropriate amount of Mn can enhance OER activity which In NCo_2.7Mn_0.3 exhibited the best OER performance.Then characterization has been focused on the typical In NCo_2.7Mn_0.3and In NCo₃ to explore their physical and electrochemical performance.The reasons for the improved OER activity after doping Mn were explained by XPS.To evaluate the utility of the antiperovskite nitride,the stability of the best performed In NCo_2.7Mn_0.3 in the chemical and electrochemical environment has been proved,which make it can not only act as a highly efficient catalyst for OER,but also a robust support for Pt to form bi-functional catalyst.Thus,the bi-functional Pt/In NCo_2.7Mn_0.3was synthesized by the ethylene glycol method,which can enables the reachargeable Zn-air battery to achieve long-term cycling performance over 100 h with high efficiency.The combination of Pt NPs with robust In NCo_2.7Mn_0.3 nitride provides a very promising alternative to the conventional Pt/C and Ir/C catalyst for rechargeable Zn-air batteries.Finally,anti-perovskite nitride In NNi₃ with high specific surface and conductivity was prepared by hydrothermal method.The physical properties of this novel nitride In NNi₃,such as its crystal structure,composition and element valence state,and so on has been illustrated.Besides,the good hydrogen evolution reaction?HER?performace and excellent stability under alkaline medium have also been demomstrated which enlighten the feasibility of In NNi₃ in the electrocatalytic field.