Bi4O5I2/nitrogen-doped hierarchical carbon (NHC) composites with tremella-like structure for high photocatalytic performance

BiOI is a visible photocatalyst towards organic pollutant. In this work, biomass waste (withered typha grass) was used to fabricate nitrogen-doped hierarchical carbon (NHC) by an one-step carbonization route. Then NHC provided a good carrier to load the BiOI semiconductor materials by a green simple co-precipitation method, after adding NaOH solution, the irregular microspheres BiOI/NHC was gradually etched by OH− to form the tremella-like Bi4O5I2/NHC. The well-defined tremella-like Bi4O5I2/NHC invested adequate interface and high particular surface range (SBET: 66 m2 g−1), which is higher than pure BiOI (22 m2 g−1) and Bi4O5I2 (17 m2 g−1). Multiple synergistic effects, such as high SBET can give more dynamic destinations, the special tremella-like structure can assimilate more reflected occurrence light of other nanosheets, low I content can increase the conduction/valence band gap of semiconductor materials and NHC can act as an electron acceptor, making as-prepared Bi4O5I2/NHC composite ideal candidates for photocatalysis. The degradation rate of Bi4O5I2/NHC reaches up to 87.4% of methyl orange in 2 h, which is about 2 times higher than BiOI and Bi4O5I2. Therefore, this work gives a technique to link NHC derived from biomass waste to Bi4O5I2 with highly-efficiency photocatalytic performance.