Application Of Modified Graphite Carbon Nitride In Alcohol-amine Coupling And NADH Regeneration

Carbon nitride has attracted great interest due to its low density,good photothermal stability,non-toxicity,and good biocompatibility.It is a photocatalyst with excellent performance.However,carbon nitride photocatalysts also face some shortcomings,such as weak absorption of visible light,easy recombination of photogenerated electrons and holes,and small specific surface area.These defects severely limit the wide application of carbon nitride in photocatalysis.In response to these problems,we have carried out structural control of carbon nitride through methods such as metal single-atom doping and chemical exfoliation to improve its photocatalytic efficiency.The main contents are as follows:（1）Single-atom Ni-supported carbon nitride photocatalyst Ni-SA@PCN was prepared by using melamine as raw material to synthesize carbon nitride sheet material by thermal polymerization,and then microwave deposition on its surface.The Ni-N₄ structure is stably anchored in the carbon nitride framework.The introduction of a single nickel atom significantly enhances the visible light absorption capability of the material,reduces its fluorescence intensity and lifetime,enhances its photocurrent intensity,and reduces its electrochemical impedance.In the visible light-catalyzed alcohol-amine coupling reaction,Ni-SA@PCN can promote the rapid coupling of benzyl alcohol and heptylamine with a final conversion rate of 73%.DFT calculations show that single-atom nickel promotes the adsorption of the reaction substrate benzyl alcohol on the catalyst surface on the one hand,and accelerates the activation of oxygen on the other hand.The bond of O=O prolonged from 1.226 to 1.371?.This part of the work demonstrates a strategy to suppress the surface charge recombination of carbon nitride by single-atom doping,which provides a new idea for designing high-performance carbon nitride photocatalysts and photocatalytic imine synthesis.（2）Using the self-assembly of melamine and cyanuric acid,intercalation of ethanol and glycerol,and thermal polymerization to obtain few-layer porous carbon nitride photocatalysts.Compared with ordinary carbon nitride,few-layer porous carbon nitride has a larger specific surface area,more abundant reaction sites,and higher charge carrier transfer and separation efficiency.In the visible light catalytic NADH regeneration test,NADH（Nicotinamide adenine dinucleotide）is a chemical substance,which is the reduced form of nicotinamide adenine dinucleotide,a reduced coenzyme,few-layer C₃N₄ achieved rapid regeneration of NADH within 7minutes,and the reaction conversion rate was as high as 71.2%,which was significantly better than that of ordinary carbon nitride photocatalysts.