Controllable Synthesis of Core–Shell Bi@Amorphous Bi2O3 Nanospheres with Tunable Optical and Photocatalytic Activity for NO Removal

The size, morphology, and structure of a Bi nanoparticle can significantly affect its photocatalytic performance. In this study, core–shell structured Bi@amorphous Bi 2 O 3 nanospheres were synthesized through a one-step solvothermal method, and the reaction mechanisms on NO removal were proposed. It was found that Bi nanoparticles can generate charge carriers by surface plasma resonance (SPR) under visible light irradiation, while the surface amorphous Bi 2 O 3 layer can facilitate the charge carriers’ separation. The Bi@Bi 2 O 3 sample with the synthesis time of 18 h exhibited superior visible light photocatalytic activity for NO degradation, attributed to the suited size and suitable amorphous Bi 2 O 3 layer. • O 2 –, 1 O 2, and • OH radicals were identified as the main reactive species involved in the photocatalysis processes. Moreover, the enhancement mechanisms of photocatalytic NO removal over Bi@Bi 2 O 3 samples were discussed. This study demonstrated that the fabrication of core–shell structured Bi@Bi 2 O 3 is a good strategy for effective air pollution control.