Construction Of LDHs Photocatalysts And Their Performance In Fuel Deep Desulfurization

Hydrotalcite compound(LDHs)is a kind of function materials.It is widely used in catalysis,adsorption,photochemical,electrochemical and other fields.Along with the continuously study,LDHs potential application in the field of photocatalysis has been exploreded.Photocatalytic performance of the single LDHs is limited,so people began to improve their semiconductor properites.There are two effective approaches for enhancing their photocatalytic performance.One is the preparation of intercalated hydrotalcite material by inserting some photocatalytic materials in hydrotalcite layers.The second is the preparation of a semi-conductor-hydrotalcite composite material,a hybrid material with properties of both semiconductor materials and LDHs.The main principle of the two methods is to produce synergistic effect between the semiconductor material and the water talc layer to improve the photocatalytic performance of hydrotalcite.At present,the application fields of LDHs based photocatalysts are mainly water treatment,oxygen production and hydrogen production.The purpose of this work is(1)to design a hydrotalcite based photocatalyst and explore its photocatalytic oxidation desulfurization performance and photocatalyst oxidation mechanism;and(2)construct a new desulfurization system by using hydrotalcite nanomaterials as catalyst,oxygen as oxidant,and acetonitrile as extraction agent.We for the first time studied the photocatalytic desulfurization performance of LDHs material.This work is of great significance for the research and development of new deep desulfurization methods.The main research contents include the following two aspects:(1)Polyacid intercalated water talc photocatalysts were prepared by using ion-exchange and exfoliation-reassembly methods,and their performance was compared preliminarily.On this basis,ZnAl-(PW12O40)x-LDHs catalyst preparaed via exfoliation-reassembly methods was shosen as catalyst studied the influence of interface structure on its photocatalytic oxidation desulfurization performance.Under optimal conditions,desulfurization rate can reach 95.3%with in 3 h.The reaction mechanism was investigated by means of XPS,PL,photocurrent(I-t)and ESR.It is found that there is a strong synergistic effect between laminar and interlayer acid.At the same time,the catalyst has good recyclability and photocatalytic oxidation performance for other sulfur substances.(2)The CoAl-LDHs/g-C3N4 composite was prepared by in-situ synthesis and applied to photocatalytic oxidation desulfurization.Under mild conditions,the desulfurization rate of 96.2%can be achieved in 2 hours.We compared the desulfurization performance of different catalyst with different portion of composition,and explored the reaction mechanism by virtue of the XPS,PL,photocurrent(I-t)and ESR explored the reaction mechanism.It is found that there is a strong synergistic effect between the LDHs and graphite carbon nitride with the formation of heterostructure.Furthermore,the catalyst showed good recycled usability,and good photocatalytic oxidation performance for different kinds of sulfur compounds.