| Graphite carbon nitride(g-C3N4)is a polymer layered material with graphene-like structure,mainly composed of two elements,C and N,with abundant reserves on the earth,a wide range of sources,and reaction conditions in liquid phase and gas phase.It has good thermal stability and chemical stability,and is non-toxic,harmless,and free of metal pollution.It has good economical and environmental protection.g-C3N4has become one of the most ideal photocatalytic semiconductor materials.g-C3N4is an excellent semiconductor photocatalytic material that does not contain any metal elements.Its band gap is about 2.7 eV.It is a medium band gap semiconductor.Its light absorption sideband is yellow,about 460 nm,and it has a certain visible light catalysis.Performance is a suitable solar energy collection medium.This article discusses how to solve the problem of photogenerated carrier recombination and the limited photoresponse range of g-C3N4catalyst.Three different g-C3N4based heterojunction photocatalysts were designed and their photocatalytic performance Through a series of characterization methods,a possible catalytic mechanism was proposed.The specific contents of them are as follows:(1)The Ti O2/g-C3N4photocatalyst was prepared by the three-step method of thermal reduction method,electrostatic adsorption supplemented by heating curing method.The results show that the Ti O2/g-C3N4heterojunction photocatalyst has a good absorption efficiency for visible light under a binary catalytic system,the photocurrent is significantly improved,the photogenerated electron-hole separation efficiency is high,the recombination probability is small,and its photocatalysis The degradation of Rh B is higher than that of pure g-C3N4or pure Ti O2/g-C3N4In particular,when the mass ratio of g-C3N4and Ti O2is 7:3,the photocurrent response intensity is increased to 6.71 times that of pure g-C3N4,to 3.61 times that of pure Ti O2.Under the conditions of 35minutes of simulated sunlight,Ti O2/g-C3N4removal rate of Rh B reached 96.1%;after five cycles of experiments,its catalytic degradation rate remained above90%,with good chemical stability;further,the synthetic samples were tested for different types of probe contamination.The degradation effect of the substance shows different degradation rates.(2)Graphite phase carbon nitride nanosheets were prepared by strong acid solvent etching and compared with the photoelectric properties of bulk graphite carbon nitride materials.The results showed that the sheet-like materials were organically degraded during photocurrent response and photocatalytic degradation.The catalytic performance of dyes has been significantly improved.Furthermore,the 2D/3D heterojunction photocatalyst g-C3N4/Mo S2based on graphite phase carbon nitride nanosheets was successfully prepared by a simple solvothermal method,and used in photolysis of water to produce hydrogen and visible light Rh B reduction to test its photocatalytic performance,the experimental results show that when the content of Mo S2increases to 3%,the photocatalytic activity reaches the maximum,with Rh B as a probe pollutant,its degradation efficiency is 4 times that of pure g-C3N4.With triethanolamine as a sacrificial agent,its photocatalytic hydrogen production rate is 16 times that of pure g-C3N4.Through a series of characterizations and tests,it is proposed that the catalytic system is a type-II heterojunction photocatalytic system after comprehensive analysis.(3)The 2D/2D/3D heterojunction photocatalyst g-C3N4/r GO/Mo S2based on graphite phase carbon nitride nanosheets was successfully prepared by simple solvothermal method and used in the photolysis of water and the reduction of Rh B under visible light to test its photocatalytic performance,its photodegradation efficiency of organic matter and the efficiency of hydrogen production by photolysis water are significantly improved.Finally,through a series of characterization methods,the catalytic mechanism scheme of the Z scheme catalytic system is proposed. |
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