Preparation Of Porous Carbon Nitride Based Heterojunction And Study On Its Photocatalytic Performance

With the prosperity of the human social economy,non-renewable resources will be depleted,environmental pollution will seriously endanger human health.Therefore,scientists are exploring new technologies to replace primary energy.Among them,photocatalytic technology is an effective way to solve this problem.Graphite carbon nitride（g-C₃N₄）as a photocatalyst has a series of advantages in solving water pollution and energy crisis.However,the photocatalytic activity of bulk carbon nitride is low due to its small specific surface area,less active sites,and easy recombination of photogenerated carriers.In this paper,efficient and stable carbon nitride-based materials were prepared by constructing heterojunctions and used in environmental purification and organic synthesis.The specific content is as follows:（1）Porous carbon nitride/tin/tin oxide（PCN/Sn/Sn O）type-II heterojunction photocatalyst with the electronic medium was synthesized by a simple method.The photocatalytic performance was evaluated by the degradation of Rhodamine B（Rh B）and the oxidative coupling reaction of Benzylamine.The results showed PCN/Sn/Sn O has the most excellent photocatalytic activity,because type-II heterojunction structure improves the separation efficiency of photogenerated electron-hole pairs,and the metal Sn as electron medium further accelerates the transfer rate of photogenerated carriers.（2）Due to the low visible light utilization of bulk carbon nitride,we synthesized ultra-thin porous carbon nitride/bismuth oxychloride/cadmium sulfide（r PCN/Bi OCl/Cd S）dual Z-Scheme heterojunction material with excellent visible light absorption by two-step deposition method.The characterization results show that excellent visible light absorption and unique dual Z-Scheme charge transfer mechanism are the main reasons for improving photocatalytic performance.（3）In this experiment,ultra-thin porous carbon nitride/bismuth oxychloride（PBovs）heterojunction catalyst with different oxygen vacancies was synthesized by adjusting the proportion of solvents in hydrothermal reactions.The results show that the oxygen vacancies are in a certain range,the photocatalytic activity of the photocatalysts will be promoted.The possible photocatalytic mechanism was proposed by trapping agent experiment and photoelectric performance characterization.