Engineering of Band Structure of Bismuth Selenide Ultrathin Nanosheets as Multifunctional Material for Photocatalytic Application

N-substituted bismuth selenide (BSN) material is synthesized by a one-step solvothermal route and used for the photocatalytic application. As-prepared BSN consists of ultrathin nanosheets and has a quasi hexagonal morphology. The results show the superior performance of BSN-2 for degradation of multi-pollutants and the ciprofloxacin and phenol removal rates reach 88.8 and 83.6%, respectively, under irradiation of simulated solar for 2 h, which is much higher than those over pristine bismuth selenide. The significant improvement of photocatalytic performance is attributed to ultrathin nanosheets structure and N introduction that contribute to the inhibition of photoelectron-hole pair recombination and the enhancement of light absorption. The possible mechanism is proposed based on characterization and theoretical calculation of the energy band structure. The results indicate that BSN-2 is a high-efficient photocatalyst for the removal of multi-organic pollutants in wastewater and this research provides a simple strategy for reasonable design and synthesis of Bi-based materials for environmental remediation.