16:45 〜 17:00
▲ [15p-D221-13] Silver Bismuth Iodide Rudorffite for Photocatalytic CO2 Reduction
キーワード：Photocatalytic carbon dioxide reduction, Silver bismuth iodide, Chemical composition engineering
Photocatalytic CO2 reduction is considered a promising strategy to resolve the global warming effect. Reducing CO2 through photocatalytic systems can convert CO2 into carbon-based fuels, such as carbon monoxide, formic acid, methanol, methane, etc. Many photocatalysts, such as including nitrides, sulfides, phosphides, and metal oxides, have been developed for photocatalytic CO2 reduction. However, a wide band gap and a short lifetime of photoinduced charges are the most common drawbacks leading to poor CO2 conversion efficiency. In this study, we developed a series of silver bismuth iodide (SBI) rudorffites, which are thought of as a next-generation photovoltaic material. A series of SBI rudorffites, including AgBi2I7, AgBiI4, Ag2BiI5, and Ag3BiI6, can be obtained by manipulating the stoichiometric ratio of silver iodide (AgI) and bismuth iodide (BiI3), and they exhibit high visible absorption ability, tunable bandgap, and suitable alignment of energy levels. The crystalline structure analysis shows that the silver-rich components exhibit hexagonal lattice structures, whereas the bismuth-rich component forms a cubic lattice structure. The crystal structure of SBI changed at a ratio of AgI/BiI3 equal to 1.0. On the other hand, a portion of Ag+ will be transformed to Ag2+ by the interaction between Bi atoms, and the valence change can be confirmed by X-ray absorption spectroscopy. The photo-assisted Kelvin probe force microscopy was used to reveal the assessment of surface charge accumulation after irradiation as SBI are struck by different light sources with different wavelengths. Finally, Ag3BiI6 exhibits the highest photocatalytic activity and can convert CO2 to CO or CH4. The averaged CO and CH4 production rates can achieve 0.23 and 0.10 μmol/g/h, respectively. Ag3BiI6 shows excellent potential as a novel photocatalysis for CO2 reduction, and it also sheds light on the possibility of solving environmental contamination and sustainable energy crises.