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 (S_BET: 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 S_BET 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.

Graphene Oxide/BiOCl Nanocomposite Films as Efficient Visible Light Photocatalysts

A novel graphene oxide/BiOCl (GO/BiOCl) nanocomposite film was prepared via a spread coating method. In visible-light photocatalytically degrading Rhodamine B (RhB) experiments, 2 wt% GO/BiOCl could degrade 99% of RhB within 1.5 h and the rate constant was 12.2 times higher than that of pure BiOCl. The degradation efficiency still kept at 80% even after 4 recycles, evidencing the relatively good recyclability. The enhancement was attributed to the improvement of visible light adsorption and charge separation. Holes and superoxide radicals· O2- played a major role as reactive species. The values of conduction band and valence band for GO and BiOCl were calculated and a new photocatalytic mechanism of GO/BiOCl nanocomposite was proposed.

Lantern-like bismuth oxyiodide embedded typha-based carbon via in situ self-template and ion exchange–recrystallization for high-performance photocatalysis

Well-defined lantern-like hierarchical Bi₇O₉I₃/NTC with superior photocatalytic activity is successfully obtained via a one-step route using in situ ion exchange–recrystallization.

Micro and nano hierachical structures of BiOI/activated carbon for efficient visible-light-photocatalytic reactions

Constructing the heterojunctions or designing the novel nanostructures are thought as effective methods to improve photocatalytic activities of semiconductors. Herein, a one-step green route was developed to fabricate bismuth oxyiodide/activated carbon (BiOI/C) composite. The prepared BiOI/C exhibit obviously red shifts and increased absorption range of visible light. The presence of Bi-C bonds confirms the heterojunction, on account of which the BiOI nanosheets tightly grew on the surface of carbon and subsequently provided the hierarchical structure, sufficient interfacial interaction and high specific surface area. Significantly, the sufficient interracial interaction is beneficial to the detachment of electrons (e⁻)-holes (h⁺) pairs and the Bi-C bonds work like a bridge to rapidly transmit the e⁻ from BiOI to carbon. What’s more, the hierarchical structure of BiOI/C efficiently shortened the diffusion pathways of pollutants and the high S_BET provided more exposed reaction sites. Benefiting from multiple synergistic effects, the as-prepared BiOI/C exhibited enhanced photocatalytic activities in degrading Rhodamine B (RhB) solution under visible light irradiation. The degradation rate of optimized BiOI/C reaches up to 95% in 120 min, and the efficiency is 3.36 times higher than pure BiOI. This study provides a promising strategy that activated carbon can be utilized in highly-efficiency photocatalysts.