Tunable 3D hierarchical graphene-BiOI nanoarchitectures: their in situ preparation, and highly improved photocatalytic performance and photoelectrochemical properties under visible light irradiation

Novel 3D hierarchical graphene-BiOI (GR-BiOI) nanoarchitectures have been successfully fabricated via an in situ self-assembly approach for the first time. More attractively, the hierarchical nanoarchitectures can be adjusted by simply controlling the amount of graphene oxide, which determines the improved level of photocatalytic performance. Photochemical measurements reveal that the as-obtained 5% GR-BiOI composite exhibits the most significantly enhanced photocatalytic activities for the degradation of Rhodamine B (RhB) and photocurrent (PC) generation under visible light irradiation (lambda > 420 nm). This remarkably improved photocatalytic performance of GR-BiOI could be attributed to the well-established interfacial interaction between graphene and BiOI, which can greatly facilitate the separation and easy transfer of photogenerated electrons and holes to generate abundant O-center dot(2)- and (OH)-O-center dot active species with powerful oxidability. This was verified by the photoluminescence (PL) spectra, electrochemical impedance spectra (EIS), active species trapping, and O-center dot(2)- and (OH)-O-center dot quantification experiments. Our work provides a new strategy for the construction of hierarchical nanoarchitectures of high-performance composite photocatalysts and paves an alternative way to the design and synthesis of graphene-based composites for special applications.