Synthesis of novel AgI/BiOI nanocomposites and their high-efficiency visible-light-driven photocatalytic degradation performance for norfloxacin

Abstract

AgI/BiOI composites were prepared with BiOI nanosheets as the substrate by in situ ion exchange and characterized by a series of characterization methods. The photocatalytic performance tests showed that the effective separation of photogenerated electron–hole pairs and the photocatalytic activities of the AgI/BiOI composites could be achieved by adjusting the Ag/Bi molar ratios, which may result in changes in the composition and structure of the AgI/BiOI composites. Among them, the AgI/BiOI-1.2 sample with a Ag/Bi molar ratio of 1.2 demonstrated a Bi₅O₇I composition and the highest separation efficiency of photogenerated electron–hole pairs, as well as the best photocatalytic performance for norfloxacin (NOR) photodegradation. More than 98.8% of NOR could be removed over AgI/BiOI-1.2 within 120 min under the optimum conditions. Radical quenching experiments confirmed that the photogenerated holes and ˙O₂⁻ radicals played significant roles during the process of photocatalytic NOR degradation. A possible Z-type heterojunction mechanism for the photocatalytic degradation of NOR over AgI/BiOI-1.2 was proposed.