Grinding-assistant synthesis to basic bismuth nitrates and their photocatalytic properties

Basic bismuth nitrates, Bi6O6(OH)(2)(NO3)(4)center dot 2H(2)O and Bi6O5 (OH)(3)(NO3)(5)center dot 3H(2)O (respectively denoted as BiON-4N and BiON-5N), were easily synthesized by a grinding-assistant room temperature reaction route through carefully tuning NaOH amounts. The plate-like BiON-5N prepared at NaOH/Bi molar ratio of 2.13 (marked as BiON-5N-2.13; pH approximate to 2.11) exhibited excellent photocatalytic activity for malachite green (MG) and methylene violet (MV) degradation under UV light illumination and the degradation efficiency arrived at nearly 100% and 93.5% within 14 min, respectively, which was obviously higher than BiON-5N prepared under lower pH values (pH = 1.34-2.02), BiON-4N (pH = 2.11-5.96), alpha-Bi2O3 (pH > 5.96), and even commercial TiO2 (P25). The excellent photocatalytic performance of BiON-5N-2.13 could be attributed to higher surface area and highly exposed (110) facets. Furthermore, BiON-5N-2.13 also possessed good photochemical and structural stability during photocatalysis process, which is crucial to potential practical application.