Study On Preparation And Performance Of Graphene Carbon Nitride Composite Photocatalysts

In the current rapid economic and social development environment,with the traditional depletion of hydrocarbon fossil fuels,human society in the near future will face a serious energy crisis.With the growing energy crisis,environmental pollution problems are gradually highlighted,especially water pollution problems are particularly prominent.Energy crisis and environmental pollution is also the world's general and urgent problems to be solved,if not improved,the long-term development of human society will not be achieved.For those who are difficult to degrade organic pollutants in water,especially persistent organic pollutants,the use of traditional treatment method has been difficult to completely remove it.Therefore,if a new technology can be developed,this technology can be difficult to degrade organic pollutants in the water while removing new energy?such as hydrogen?,in order to achieve pollution control and energy synchronization,which is not only conducive to environmental pollution of governance,but also help to ease the energy crisis.Therefore,the research and application of N-GQDs/CNU and CDs/CdS/CNU composite semiconductor photocatalyst in photocatalytic hydrogen production and removal of pollutants and synchronization are studied in this paper.The effects of different morphology,different polymerization methods and different protonation degree on the photocatalytic effect were systematically studied by using the g-C₃N₄ catalyst obtained from different precursors?urea,dicyandiamide and melamine?by calcination.On the basis of the introduction of different proportions with good light absorption of N-GQDs.The results show that N-GQDs can enhance the catalytic effect of photocatalyst.When the loading amount of N-GQDs is 15%,the photocatalytic effect is the best.Under the light,the photocatalytic activity of the composite catalyst 15N-CNU The photocatalytic hydrogen production rate is 2.16 times higher than that of pure g-C₃N₄,the hydrogen production rate is 2.18 mmol·g-1·h-1,and the corresponding quantum efficiency is5.25%.In addition,this paper proposes a catalyst with good photocatalytic degradation of organic pollutants and photocatalytic decomposition of hydrogen hydride catalyst to form heterojunctions,so as to construct a highly efficient and stable organic pollutant photocatalytic degradation and simultaneous decomposition of aquatic hydrogen of the photocatalytic system,the ultimate realization of organic wastewaterremoval and simultaneous mineralization.We synthesized the CdS/CNU heterojunction catalysts with different ratios of CdS quantum dots by solvothermal method.The catalysts can photocatalytic degradation of p-nitrophenol and simultaneously photocatalytic hydrogen evolution.On this basis,we will have a good light absorption of CDs introduced,the synthesis of CDs/CdS/CNU heterojunction photocatalyst.The experimental results show that the photocatalytic effect is best when the loading?wt%?of CDs is 3%,the removal rate of p-nitrophenol is 98%,the hydrogen production rate is up to 25 ?mol·h-1·g-1.The In addition,we also systematically studied the synergistic-inhibitory effect of photodegradation and photocatalytic hydrogen production of different pollutants...