Tailoring structural and photocatalytic features of nitrogen-doped Bi₂MoO₆ structures under different nitrogen sources

The present research aimed to obtain Bi₂MoO₆ and nitrogen-doped Bi₂MoO₆ compounds capable of extending their light absorption capability toward the visible regime through nitrogen doping of those structures. It were obtained employing a high pressure-hydrothermal method assisted by microwave heating by using different nitrogen precursors including urea, thiourea, hydrazine, and ethylenediamine. The effect of nitrogen precursors on the physicochemical and structural properties was investigated in detail through scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectroscopy, and specific surface area determination using the BET method. The energy bandgap was calculated by UV–Vis spectroscopy, which exhibits high absorption from the UV region up to the visible regime. Nitrogen-doped Bi₂MoO₆ compounds show high specific surface area values as well as a reduction in their bandgap energy values compared to pristine Bi₂MoO₆. Regarding the influence of the different nitrogen sources, it was observed that thiourea provided the highest percentage of nitrogen content in the Bi₂MoO₆ structure (15.76 at. %), while hydrazine showed the highest specific surface area (11.01 m²/g). The compounds showed a positive effect, reaching a degradation of 66% under UV and 68%, under Vis irradiation of the lignin molecule. Also, the results indicate that the N-doped Bi₂MoO₆ compounds are more active than the pristine Bi₂MoO₆. The methodology presented here provides an easy and low-cost way for the synthesis of Bi₂MoO₆ structures with potential use in the field of photocatalysis.