Facile route for C-N/Nb 2 O 5 nanonet synthesis based on 2-methylimidazole for visible-light driven photocatalytic degradation of Rhodamine B.

Herein, we fabricated a C and N co-modified Nb 2 O 5 nanonet structure (C-N/Nb 2 O 5 NNs) from niobium oxalate using 2-methylimidazole (Hmim) as a source for C and N via a simple hydrothermal route. The obtained nanonets are robust and cost-effective with excellent recycling stability. Compared with N-doped TiO 2 (N-TiO 2 ) and a Nb 2 O 5 control sample (Nb 2 O 5 -CS), the resulting nanonets exhibited the highest performance toward the photocatalytic degradation of Rhodamine B (RhB) upon visible light irradiation ( λ > 420 nm). Through this study, we revealed that the synergetic effects of C and N on the nanonet surface, which were effectively incorporated into the surface of the Nb 2 O 5 nanonet structure, not only remarkably enhanced the visible light response by decreasing the bandgap to 2.9 eV but also improved the light utilization efficiency and photo-induced electron-hole pair separation efficiency of our nanonet structure. We also proposed that the presence of carbonate species (CO x ) and nitrogen species (NO x ) increased the population of generated holes (h + ) that had the key role in the photodegradation mechanism of RhB, suggesting reasonable importance for the modification of Nb 2 O 5 with C and N. This synergism offers a new view to reveal the origin of photodegradation processes, introducing h + as a key intermediate. Our approach provides a new insight to design 2D nanostructures with potential applications in catalysis, solar energy conversion, and environmental protection.