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Synthesis And Photocatalytic Performance Of Element-doped And Semiconductor Compound Modified Carbon Nitride

Posted on:2021-03-04Degree:MasterType:Thesis
Country:ChinaCandidate:Q ZengFull Text:PDF
GTID:2381330611497263Subject:Chemical engineering
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With the development of industrial economy,energy consumption and environmental protection have become two major difficulties that need to be solved urgently in today's society.Faced with the dual pressure of environment and energy,photocatalytic technology dominated by non-precious metal semiconductors has been widely developed in order to effectively alleviate these two problems.Among them,graphite carbon nitride?g-C3N4?has received extensive attention in photocatalytic technology due to its special two-dimensional morphology,excellent photochemical properties and adjustable band gap width.However,it still has shortcomings,such as the easy recombination of photogenerated electron-hole pairs,low specific surface area and low visible light absorption,which limit its photocatalytic activity.At present,researchers have successfully enhanced the photocatalytic activity of g-C3N4through modification methods such as element hybridization,morphological control,and semiconductor assembly.This paper focuses on carbon nitride as the research object,and the specific research results are as follows:?1?Using melamine as raw materials,potassium hydroxide and potassium chloride as K sources,K-doped CN was successfully prepared,and on this basis,K and P co-doped CN were explored.The results show that under the irradiation of visible light,K-doped CN exhibits enhanced hydrogen production activity,which is 1.9 times that of CN.K and P doping can enhance the absorption of light by CN,increase the range of light response,reduce the band gap width,and promote the migration of photogenerated electron-hole pairs.?2?Using melamine as the main material and phosphoryl chloride trimer as the phosphorus source,a phosphorus-doped carbon nitride catalyst was synthesized by hydrothermal and calcination methods.The research results show that the introduction of P atoms and hydrothermal treatment increase the absorption intensity of carbon nitride in the visible light region,reduce the recombination rate of photo-generated electron-hole pairs,and reduce the resistance to carrier migration for better performance.Rapid transfer,which greatly increases the photocatalytic activity of the sample.In the visible light region,whether it is to degrade Rhodamine B or photolyse water to produce hydrogen,the doped materials exhibit excellent photocatalytic activity.?3?Using melamine as the raw material,sodium hypophosphite as the P source,and nickel chloride hexahydrate as the Ni source,the Ni2P-CN composite was successfully prepared.The results show that Ni2P recombination can enhance the absorption of light by CN,increase the range of light response,and reduce the band gap of CN,which helps the separation and migration of photogenerated electron-hole pairs.Ni2P recombination can also effectively inhibit the recombination of photogenerated electron-hole pairs.Under 1h visible light irradiation,the hydrogen production of Ni2P-CN?5%?is 1.4 times that of CN,and it has good photocatalytic stability.
Keywords/Search Tags:graphite carbon nitride, K doping, P doping, nickel phosphide, photocatalysis
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