Diethanolamine-functionalized BiOI hollow microspheres with negative conduction bands maximize the visible light photocatalytic performance for CO 2 reduction

Bismuth iodide oxides have a wide range of applications as visible light photocatalysts in CO2 reduction reactions. While formation of heterostructures between semiconductors has been actively used to enhance catalytic reduction performance, the functional groups used to improve the separation ability of electron/holes (e-/h+) and surface energy band positions of BiOI surfaces have been rarely mentioned. Here, a new modification strategy was reported to improve the photocatalytic performance using solvents with hydroxyl functional groups to change the surface structure of BiOI hollow microspheres. Intriguingly, the BiOI hollow microspheres functionalized using diethanolamine have a larger negative surface conduction band than BiOI. Thus the photogenerated electron reduction capacity of the diethanolamine-functionalized BiOI is greatly enhanced, which can be obtained from the yield of reduction reaction testing and characterization results. This hydroxyl functional group modified BIOI provides a new strategy for improving photocatalytic performance. The DFT simulation provides a theoretical basis for photocatalytic CO2 reduction.