Preparation Of La-Ni-O Based Catalysts And Their Application In Environment And Energy

Energy crisis and environment pollution have aroused extensive attentions in the past few decades because of increased energy consumption and human activity.As the development of industry and population expansion,there has been an increasing demand in the treatment of industrial wastewater containing toxic pollutants.Hydrogen,which is a clean and high calorific energy resource compared to fossil fuels,is considered to be the major energy carrier in the future.Among various catalytic pollutants degradation and H₂ evolution paths,the photocatalytic technique is increasingly under the spotlight,duo to the fact that the system is simple and sustainable,and solar energy could be utilized directly.As a typical semiconductor,titanium dioxide has attracted lasting concern due to its low toxicity,low cost,excellent chemical stability and high activity.However,as a result of its wide band gap,UV light excitation and low quantum efficiency?QE?,the practical application of TiO₂ has been prohibited.So it is significant to develop a simple catalytic activity and new materials used in pollutant degradation and H₂ evolution.In this paper,several high efficient catalytic materials were designed to solve the existing problems,which mainly include the material of La₄Ni₃O₁₀0 particle,La₂NiO₄sphere,porous La₂NiO₄ nanosheet.And the pollutant degradation and H2 evolution performance were evaluated as well.The research was mainly composed of the following parts:?1?The Ruddlesden-Popper type of La_n+1Ni_nO_3n+1 materials was synthesized by EISA?Evaporation-Induced Self-Assembly?method with the PEG20000 template after calcination,and characterized by XRD,XPS,EIS and so on,to verify the activity mainly influenced by oxygen content in La_n+1Ni_n O_3n+1n+1 structure and electron mobility rate,and obtained the optimal structure of catalysts.Meanwhile,the BET,TEM results indicated that the La₄Ni₃O₁₀ catalyst exhibits smaller particle size,high surface area and homogeneous-dispersed through EISA method.The high pollutant degradation activity in dark is attributed to high surface area and unique structure of La₄Ni₃O₁₀.?2?Although the La₄Ni₃O₁₀ particle exhibits high activity in dark,the poor stability of La₄Ni₃O₁₀ particle restricts its widely application.Thus we fabricated a La₂NiO₄hollow nano-sphere catalyst with high stability.The La₂NiO₄ precursor was synthesized via a hydrothermal method,the La₂NiO₄ hollow nano-sphere sphere was obtained after calcination,and characterized by BET,TG-DTA,HRTEM,XRD and so on.The La₂NiO₄ sphere has high crystalline,uniform particle size,high surface area and superior stability.The catalyst shows excellent round-the-clock pollutant degradation activity in dark,or under visible light and infrared light,attributing to its unique structure,high surface area and efficient light absorption.?3?We further studied a pure La₂NiO₄ nanosheet photoelectrocatalyst applied in the reaction of urea oxidation cell by GO template,and characterized by XRD,BET,TEM and FESEM to verify its layered perovskite crystal structure.The La₂NiO₄nanosheet possesses porous structure and high surface area.Then we deposited it on the surface of FTO to perform photoelectrocatalytic experiment.The porous La₂NiO₄nanosheet shows high urea oxidation and H₂ evolution activity.We studied its urea oxidation ability by electrochemical test,the porous La₂NiO₄ nanosheet exhibits higher photocurrent compared with bulk La₂NiO₄ catalyst.The urea oxidation activity is more superior even than commercial Pt/C electrode.Moreover,the porous La₂NiO₄nanosheet shows strong stability during urea oxidation process.