Preparation And Photocatalytic Performance Of M²⁺-SnO_2-x/g-C₃N₄ Z-scheme Photocatalyst

Semiconductor photocatalysis technology is an emerging technology that uses semiconductor materials as catalysts to catalyze the degradation of organic pollutants,photolysis of water to prepare H₂,and catalytic reduction of CO₂ to prepare CH₄.It is an emerging technology for treating environmental pollution and solving energy shortages.These two major issues have very broad prospects for development and have received widespread attention.The performance of semiconductor photocatalytic materials is affected by many factors such as the light absorption capacity of the material,the separation efficiency of photogenerated carriers,the redox capacity of photogenerated carriers,and the transfer efficiency of photogenerated carriers.According to literature reports,doping transition metal ions to introduce defects and constructing a Z-scheme heterojunction is an effective solution to improve the photocatalytic performance of semiconductor materials.In this paper,SnO₂ and g-C₃N₄ are the main research objects.The energy band structure of M²⁺-SnO_2-x is adjusted by doping Zn²⁺or Sn²⁺metal ions into SnO₂,and the Z-scheme heterojunction M²⁺-SnO_2-x/g-C₃N₄ photocatalyst controllable construction is combined with g-C₃N₄,the specific research content is as follows:Zn²⁺-SnO_2-x/g-C₃N₄ Z-scheme heterojunction:Zn²⁺-SnO_2-x semiconductor material was successfully prepared.EDS analysis showed that Zn element is uniformly distributed on SnO₂ semiconductor,and the doping ratio of tin and zinc is 1:0.05 The photocatalytic performance of Zn²⁺-SnO_2-xsemiconductor material is the best,and the degradation rate of rhodamine B dye in 90 minutes is 4 times that of pure SnO₂;in the Zn²⁺-SnO_2-x/g-C₃N₄ composite sample,SEM analysis found that Zn²⁺-SnO_2-x-0.05 is uniformly attached to the surface of g-C₃N₄,and the sample with a mass fraction of 50%has the best photocatalytic performance,and the degradation rate of rhodamine B is increased to 83%,which is 2 times of Zn²⁺-SnO_2-x-0.05 and 1.6 times of g-C₃N₄;Mott-Schottky curve analysis shows that the carrier transport mechanism of Zn²⁺-SnO_2-x/g-C₃N₄ is Z-scheme transmission,and Zn²⁺-SnO_2-x/g-C₃N₄ Z-scheme heterojunction photocatalyst was successfully prepared.Sn²⁺-SnO_2-x/g-C₃N₄ Z-scheme heterojunction:Sn²⁺-SnO_2-x semiconductor nanomaterials were successfully prepared by controlling the hydrothermal reaction time.The experimental results of photocatalytic degradation of rhodamine B showed that the doping of Sn²⁺reduced the forbidden band width of SnO₂and the photocatalytic performance of Sn²⁺-SnO_2-x semiconductor material with the reaction time of 4h is the best.The degradation rate of rhodamine B dye in 90 minutes is 5times of pure SnO₂;Sn²⁺-SnO_2-x/g-C₃N₄composite The analysis of nanomaterials showed that Sn²⁺-SnO_2-x was uniformly attached to the surface of g-C₃N₄.Among them,the sample with 50mg of g-C₃N₄ has the best photocatalytic performance,and the degradation rate of rhodamine B is increased by nearly 1.2 times compared with g-C₃N₄;Mott-Schottky curve,analysis shows that the prepared Sn²⁺-SnO_2-x/g-C₃N₄ is a Z-scheme heterojunction photocatalytic material.