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Study On Preparation Of Bimetal Composite Photocatalyst And The Synergistic Hydrogen Production By Degradation Wastewater

Posted on:2019-08-15Degree:MasterType:Thesis
Country:ChinaCandidate:C DaiFull Text:PDF
GTID:2371330548463267Subject:Chemical Engineering and Technology
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Energy as the foundation of human society development,with the use of traditional fossil energy,human society has realized the transformation from agricultural Society to industrial society.However,since entering the new century,the environmental pollution and the unsustainable nature of the traditional fossil energy use have made people have to consider the new type of alternative energy.Photocatalytic technology,because of its mild reaction depth,can directly use sunlight as a reaction driving force,which is considered as an ideal technology to solve environmental pollution and provide clean energy.In this paper,the traditional catalyst TiO2?P25?and the new polymer semiconductor photocatalyst g-C3N4 as the main catalyst,combined with the surface plasmon resonance effect?LSPR?and the synergistic effect of the cocatalyst,the two kinds of catalysts were used to carry out nano-bimetallic load and the plasma ternary composite catalysts were constructed.Increased solar spectrum utilization and separation efficiency of electron-hole pairs.XRD,SEM,FT-IR and DRS were used to characterize the plasma ternary composite photocatalytic materials.First,using a simple chemical reduction method,using TiO2?P25?with anatase and rutile phase as the main catalyst,a bimetallic nano Ag/Cu@P25 composite catalyst was prepared.Using glycerol as a sacrificial reagent,the effect of hydrogen production activity at different Ag/Cu loadings was investigated.The experimental results show that the activity of the catalyst has been greatly improved after the bimetallic nano Ag/Cu loading compared to the single-metal loading and the pure TiO2?P25?.The spectrum absorption range of the catalyst is extended to the visible spectrum,and the combination of electron-hole pairs is also suppressed.CAT-2 has the best hydrogen production activity,its hydrogen production effect under visible light reaches 6368.20?mol.g-1.h-1,and the hydrogen production activity under the whole spectrum is 25811.51?mol.g-1.h-1.11.55 times that of pure TiO2?P25?.And it has good photocatalytic stability under visible light.Based on the experimental and characterization,the possible reaction mechanism of the bimetallic nanoAg/Cu@P25composite catalyst was investigated.Second,bimetallic Ag/Cu@g-C3N4 catalysts were prepared by thermal polymerization,thermal oxidation etching and chemical reduction precipitation.The effect of bimetallic nano Ag/Cu on the hydrogen production of graphite-like g-C3N4was studied.The experimental results show that Ag/Cu@g-C3N4?0.5ACG?has higher hydrogen production activity than Cu@g-C3N4?0.5CG?,Ag@g-C3N4?0.5AG?and g-C3N4.The hydrogen production activity under visible light is 326.18?mol.g-1.h-1,which is 4.96 times that of the pure g-C3N4 nanosheet.The hydrogen production activity under the full spectrum is 2886.48?mol.g-1.h-1.8.35 times that of g-C3N4nanosheets.At the same time,the possible reaction mechanism of Ag/Cu@g-C3N4was studied,that is,the LSPR effect of Ag and cocatalyst Cu have synergistic catalytic effect on the promotion of photocatalytic hydrogen production.Thirdly,photocatalytic bimetallic nano Ag/Cu@P25 ternary composite catalyst was selected as photocatalytic degradation material for hydrogen production.The glucose simulated wastewater was degraded for hydrogen production experiment.The single factor and orthogonal experiment were used to determine the most Good process:The amount of photocatalyst added is 0.01 g,the pH of the reaction solution is 8,the glucose concentration of the reaction solution is 1.0g/L,and the reaction time is 5 hours.The best process validation results:hydrogen production rate of1628.3?mol.g-1.h-1,CODcr degradation rate of 36.96%.Fourth,on the basis of degrading hydrogen production from simulated wastewater,the production wastewater of a fructose processing company in Jiangxi was degraded to produce hydrogen.The optimum process conditions were determined as follows:the amount of photocatalyst added was 0.015g,the pH of the reaction solution was 8,the actual dilution ratio of the wastewater was 2 times,and the reaction time was 6 hours.The best process validation results are as follows:hydrogen production rate is 1420.56?mol.g-1.h-1,CODcr degradation rate is 31.15%.The effect of synergistic hydrogen production by degradation has been achieved.
Keywords/Search Tags:Chemical reduction, Thermal polymerization, Thermal oxidation etching, Photocatalysis, Hydrogen production, Degradation
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