Asymmetric structure engineering of polymeric carbon nitride for visible-light-driven reduction reactions

Abstract

The photocatalytic activity of polymeric carbon nitride (g-C 3 N 4 ) strongly depends on its electronic structure which is highly sensitive to the preparation methods. To design the photocatalysts with efficient charge separation and transfer property, here we report a new ethylenediamine (EDA) induced gas-solid grafting method which enables the asymmetric modification of g-C 3 N 4 featuring the aromatization at the terminal of melon motifs. The obtained terminal-aromatized g-C 3 N 4 (Ar-C 3 N 4 ) exhibits an improved visible-light-driven photocatalytic activity in versatile two-electron reduction reactions, outperforming the pristine g-C 3 N 4 by 15.4 and 6.6 folds respectively in hydrogen evolution and hydrogen peroxide production. Theoretical and experimental results demonstrate the intensified asymmetry of π-electron distribution in the resulting material, which provides significantly improved driving force to guide the efficient separation of photogenerated e-h pairs and enhance the charge carrier mobility compared to its symmetric counterpart. ● Asymmetric modification of g-C 3 N 4 is developed via a new EDA involved gas-solid grafting process. ● The structure demonstrates lopsided arrangement of melon-based motifs featuring aromatization of terminal groups. ● Intensified asymmetric electron distribution is constructed. ● Significantly enhanced photocatalytic two-electron reductions are obtained.