First-Principles Study of Sc, B Doped g-C3N4/TiO2 Heterojunctions for Enhanced Photocatalytic Performance

The first-principles method based on density functional theory was used to study the cell structure properties, electronic properties, and photocatalytic performance of g-C3N4/TiO2 heterojunctions and Sc, B monodoped and co doped g-C3N4/TiO2 heterojunctions. The results show that both TiO2 and g-C3N4 crystals have good structural stability. The interaction between the g-C3N4 monolayer and the TiO2 (101) surface forms a van der Waals heterojunction, which has the advantages of narrow bandgap, wide light response spectrum bandwidth, and high carrier migration efficiency. It can effectively solve the problem of high energy consumption in the degradation process of organic pollutants. The heterojunction model before and after doping is reasonable and feasible, with narrow band gaps that can effectively suppress photo generated electron hole pair recombination. The interlaced band structure of the two crystals in the heterojunction promotes charge separation and carrier migration. The doping of Sc and B introduces hybrid states, which not only regulates the redox ability but also further reduces the band gap. Among them, co doping has the most significant effect, at 2.178 eV, accelerating charge transfer, causing the absorption edge of the system to shift red, increasing the response range in the visible light region, enhancing the absorption performance, and exhibiting better photocatalytic performance.