The Preparation Of Transition Metal Oxides And Their Performance For Ammonia Synthesis

As one of the most important parts of chemical industry,ammonia synthesis industry is indispensable in national economy.However,the low conversation rate per pass,the huge energy consumption,the use of the fossil fuel and the discharge of greenhouse gas exist in conventional process of the traditional ammonia synthesis method.Therefore,the ammonia synthesis at low temperature and atmospheric pressure has caused great concern because of its advantages like lower energy consumption,environmental and safety protection.In this case,low-cost and superior performance catalysts would play a very crucial role in the ammonia synthesis at low temperature and atmospheric pressure.Transition metal oxides are used as outstanding catalysts,which have merits that they are easy to get and their structure and properties are easy to adjust.In this paper,transition metal oxides are synthesized by hydrothermal method to catalyze the reaction of ammonia synthesis at low temperature and atmospheric pressure.In this paper we used ascorbic acid and potassium permanganate as raw materials to synthesize ?-MnO2 by hydrothermal method,also,we used cobaltous chloride,triethanolamine as raw materials to synthesize Co3O4 by hydrothermal method and high-temperature calcinations.We used XRD to characterize the catalyst's composition and structure.Then,we used the catalysts in electrochemical ammonia synthesis to evaluate their electrochemical performance at low temperature and atmospheric pressure.As for the result,the catalysts all successfully synthesized ammonia in our experiment.The catalyst with most activities in our work is P-MnO2,whose best reaction condition is 1.4 V and 90?.The highest ammonia formation rate of?-MnO2 came up to 2.30×10-10 mol·cm-2·s-1,with the current efficiency at 4.12%.The best reaction condition of activated carbon was 1.4 V and 90?,The highest ammonia formation rate of ?-MnO2 came up to 2.30×10-10 mol·cm-2·s-1,with the current efficiency at 4.89%.The best reaction condition of Co3O4 was 1.4 V and 90 0C,The highest ammonia formation rate of(3-MnO2 came up to 2.30×10-10 mol·cm-2·s-1,with the current efficiency at 4.56%.