Performance Regulation And First-principles Study Of G-C₃N₄ And BiOBr Photocatalytic Materials

The photothermal technology has attracted significant attention due to its high efficiency and environmental benefits.However,traditional photothermal materials have limitations in terms of photocatalytic efficiency and stability.Therefore,it is crucial to research new types of photothermal materials to enhance their performance.This research paper primarily focuses on studying the photocatalytic performance of P and Ce co-doped g-C₃N₄ and the composite material BiOBr/g-C₃N₄,with validation using Density Functional Theory（DFT）calculations.The specific research content is as follows:P and Ce co-doped g-C₃N₄ photocatalysts were successfully synthesized using a thermal polymerization method.The phase structure,morphology,electronic properties,and optical properties of the material were thoroughly investigated using techniques such as XRD,FT-IR,SEM,BET,XPS,UV-Vis-DRS and PL.The photocatalytic experiments demonstrated that the P and Ce co-doped g-C₃N₄ nanosheets exhibited the highest photocatalytic activity,with a degradation efficiency of 87.91%for Rhodamine B（Rh B）,significantly higher than other samples.DFT calculations verified the photocatalytic mechanism of the experimental results from the perspectives of band gap,density of states,and light absorption coefficient.The calculated band gap values showed some deviation from the experimentally measured values but exhibited consistent trends,indicating that the doping of P and Ce can reduce the band gap of g-C₃N₄ nanosheets.The BiOBr/g-C₃N₄ composite material was prepared by a solvothermal method,and its application in photocatalysis was investigated.The experimental results showed that the composite material had a rough and porous surface,which increased the specific surface area and the number of reactive sites.The combination with g-C₃N₄ improved the utilization efficiency of solar energy and broadened the light absorption range of BiOBr.The photocatalytic experiments demonstrated that the composite g-C₃N₄ significantly enhanced the photocatalytic activity of BiOBr towards Rh B.The optimum degradation rate of Rh B reached 95.36%when the content of composite g-C₃N₄ was 0.2 mmol.DFT calculations revealed that the band gap of the BiOBr/CN_0.2 heterojunction was 2.13 e V,with an S-type band alignment,enabling efficient separation and transfer of photogenerated electrons and holes.The construction of the heterojunction also widened the light absorption range and enhanced light absorption intensity,leading to significant improvements in the optical properties of the BiOBr/CN heterojunction within the visible light range,demonstrating excellent photoelectric performance.