A 2D/3D g-C3N4/BiOI heterostructure nano-sphere with oxygen-doped for enhanced visible light−driven photocatalytic activity in environmental remediation

Adjusting the desired structure and heterojunction interface of photocatalytic materials using a facile and efficient strategy is still challenging. In this study, a novel two-dimensional/three-dimensional (2D/3D) oxygen-doped g-C3N4/BiOI heterostructure nano-sphere (O-g-C3N4/BiOI) was successfully prepared by a facile solvothermal method for the degradation of nondye organic contaminants. Its composition, morphological characteristics, chemical structure and electrochemical properties have been measured. The result shows the introduction of oxygen doping (O-doping) causes a new defect energy level, extends the light absorption range, and the formation of heterojunction enables the effective separation of photo-generated carriers. Under visible light irradiation, the optimum ratio of O-g-C3N4/BiOI (2:1) exhibited 100% removal efficiency of bisphenol A within 80 min, which was about 9.1, 2.33, 3.45, and 1.6 times that of pure g-C3N4, O-g-C3N4, BiOI, and O-doped-poor heterostructure, respectively. Based on the identified intermediates, the photocatalytic mechanism of O-doped O-g-C3N4/BiOI (2:1) was also revealed. This finding suggested that the synergistic effect between 2D/3D heterojunction and O-doped greatly promoted visible light photoabsorption and photoinduced carrier separation efficiency with a prolonged lifetime, which was confirmed by multiple optical and electrochemical analyses. This study could bring new opportunities for the rational design of highly efficient photocatalysts by combining 2D/3D heterojunctions with O-doped in environmental remediation.