Solar‐Driven Fixation of Bismuth Oxyhalides on Reduced Graphene Oxide for Efficient Sunlight‐Responsive Immobilized Photocatalytic Systems

Developing green, cheap technology for large‐scale production of photocatalysts in colloidal dispersion form enables the fabrication of efficient sunlight‐responsive immobilized photocatalytic systems to address current environmental issues. It is reported for the first time, a cost‐effective, energy‐efficient, green, single‐step approach for solar‐driven fixation of bismuth oxybromideiodied solid solution (BiOBr0.75 I0.25 SS) on reduced graphene oxide (rGO) sheets by solar light irradiation of BiOBr0.75I0.25‐graphene oxide (GO) dispersion in ethanol medium. Upon solar irradiation, GO is photocatalytically reduced by BiOBr0.75I0.25, resulting in uniform fixation of BiOBr0.75I0.25 SS on rGO to yield high‐purity BiOBr0.75I0.25‐rGO heterojunction (BiOBr0.75I0.25‐rGO HJ) in colloidal dispersion form. The solar‐driven fixation of BiOBr0.75I0.25 SS on rGO brings many favorable characteristics for BiOBr0.75I0.25‐rGO HJ as sunlight‐responsive photocatalyst over the pristine BiOBr0.75I0.25, including high absorption of light in the visible region, high electron‐hole separation efficiency, and super adhesive property. As a result, BiOBr0.75I0.25‐rGO HJ films exhibit super durability and outstanding photocatalytic performance for water decontamination over BiOBr0.75I0.25 films under the same conditions. This study is an establishment of a green strategy for the large‐scale production of rGO‐based bismuth oxyhalides HJs. This work introduces a cost‐effective, energy‐efficient, green, single‐step, and scalable synthetic strategy for a uniform fixation of bismuth oxyhalides on reduced graphene oxide sheets solely using abundant solar light irradiation. The produced materials are in colloidal dispersion form enabling the fabrication of large‐scale sunlight‐responsive immobilized photocatalytic systems using typical coating techniques.