The Construction Of LDHs-based Layered Nanocompositeand It’s Photocatalytic Reduction Of Nitrogen

Nitrogen is the most abundant gas in the atmosphere and an important source of nitrogen.Ammonia(NH3)is one of the most important chemical basic substances in human production and life.However,the industrialized main body still uses the Haber Bosch process discovered in the twentieth century.The synthesis conditions of this process need to be carried out under high temperature and high pressure,and cause great pollution and waste to the environment and resources.Therefore,the search for a catalyst for clean and high-efficiency reduction of nitrogen is an important research topic in the field of energy.In recent years,layered metal hydroxide LDHs have been discovered and explored by researchers.Because of its many advantages such as inter-layer controllability,memory effects,etc.More and more LDHs-based composite materials appear in people’s lives.It plays an increasingly important role in the fields of photocatalytic reduction of carbon dioxide,photolysis of water and photodegradation of fuel.The specific work is as follows:1:A series of different atomic ratios of NiV-LDHs were prepared by urea method and organic solvent mixing method(AMO),which were 1:1,2:1,3:1,4:1,5:1.The hydrotalcites synthesized by different methods were applied to the experiment of photocatalytic reduction of nitrogen.It was found that the hydrotalcite prepared by the AMO method has a larger specific surface area than the urea method,and can adsorb more nitrogen,so that the catalytic efficiency is better.Exploring the nitrogen fixation efficiency of hydrotalcite in different proportions,it was found that the catalytic efficiency of NIiVi-LDHs was better than 490 μmol/L.The experimental exploration showed that these catalysts have great potential for photocatalytic nitrogen fixation.2:By hydrothermal co-precipitation method,the organic molecule P C(tetracycline tetraphthalate tetrasulfate)and PTCB(3,4,9,10-decane tetr acarboxylic acid)were opportunely lead into Ni2Fe-LDHs.The interlaye r of Ni2Fe-LDHs and the prepared catalyst were applied to the experim ent of photocatalytic reduction of nitrogen,and ammonium ions were fo und in the product.It was found that the introduction of small organic molecules between the layers of hydrotalcite greatly improved the efficie ncy of catalytic reduction of nitrogen,with the highest efficiency reachi ng 390μmol/L,which is twice the efficiency of Ni2Fe-LDHs hydrotalcite.The energy band structure of the catalyst is comfortable for the reductio n reaction of photocatalytic nitrogen.The selected organic molecule as a n electron donor-receptor,which accelerates the photoinduced charge tran sfer and reduces the electron-hole recombination rate,so the efficiency of photocatalytic reduction of nitrogen is improved.The preparation proc ess of the organic molecular intercalated hydrotalcite catalyst is relativel y simple,and the raw material price is low and easy to obtain.It is be lieved that such materials will have a good development space in the fi eld of catalysis in the future.3:Ni2V-LDHs and MXene were combined together by in-situ growt h method to prepare a series of catalyst powders with different composi tions,which were used in the experiment of photocatalytic reduction of nitrogen,and ammonium ions were detected in the product.In the expe riment,it was found that the catalysts which were combined together w ere more efficient than Ni2V-LDH and MXene alone in photocatalytic re duction of nitrogen.MXene is a kind of conductor,which enhances the electron transport ability during the experimental reaction,so that the ca talytic efficiency is improved after the combination of the two.Such cat alysts have lower cost and simple preparation process,and it is believed that they have a good future in the research of photocatalytic reduction of nitrogen.