Recently, Wang Jiahong and Yu Xuefeng of the Material Interface Research Center of the Institute of Materials Research, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences have made new progress in the large-scale preparation and application of a new type of crystalline phosphorus. The related work was published in the top chemistry journal Angewandte Chemie International Edition ("German Chemistry") with the title "Crystalline Red Phosphorus Nanoribbons: Large-Scale Synthesis and Electrochemical Nitrogen Fixation" ", impact factor 12.257, DOI: 10.1002/anie.202006679). The co-first authors of the paper are Dr. Liu Qian and Dr. Xue Zhang, and the corresponding authors are Associate Researcher Wang Jiahong and Researcher Yu Xuefeng.
Due to the advantages of high specific surface area, high stability, large number of active sites, and easy adjustment and control, two-dimensional materials have shown huge application potential in the field of energy catalysis. Unlike traditional isotropic nanosheets, the two-dimensional nanoribbon material has stronger lateral size limiting effect and directional transmission characteristics, which is beneficial to expose more edge sites and improve the charge transfer efficiency. For the preparation of optoelectronic devices and energy conversion Application is essential. Since the discovery of two-dimensional black phosphorus as a direct bandgap semiconductor, the preparation of two-dimensional structures of phosphorus materials has received widespread attention. Red phosphorus is its common phosphorus allotrope, which has the advantages of wide light response range, narrow forbidden band width, stable chemical properties, low cost, and environmental protection. Among them, triclinic red phosphorus (cRP) has a two-dimensional layered structure like black phosphorus, and the single layer is composed of a simple elemental unit of tubular phosphorus, which is naturally suitable for preparing a two-dimensional nanoribbon structure of crystalline red phosphorus. However, due to the lack of effective synthetic methods, the research and application of crystalline red phosphorus have been seriously hindered.
In this study, the research team realized for the first time the rapid and large-scale synthesis of high-purity cRP single crystals at a relatively low temperature (480°C) and a short period of time (20 hours). The conversion rate of raw materials is about 99%, and the single output is up to 10 grams, showing the potential for further industrialization. The large-scale preparation of cRP crystals has laid the foundation for the synthesis of a large number of single-layer or few-layer cRP nanoribbons (cRP NRs). After ultrasonic treatment of the probe, the high-quality cRP single crystal is stripped into a single layer or a few layers of nanoribbons (thickness less than 20 nm, average width about 120 nm). Theoretical and experimental studies have shown that cRP NRs have an efficient and stable electrochemical nitrogen fixation activity. In 0.1 M Na2SO4 electrolyte, the ammonia production of cRP NRs at -0.4 V (relative to the reversible hydrogen electrode) was 15.4 μg h-1 mg -1cat. The Faraday efficiency at -0.2 V was 9.4%. In further research by the research team, the isotope labeling was used to verify the source of nitrogen and eliminate the interference of impurities, and combined with colorimetric analysis to determine the yield and reproducibility of NH3.
This research work synthesized crystalline red phosphorus on a large scale, revealing that crystalline red phosphorus nanoribbons are an effective non-metallic ammonia synthesis catalyst. The successful preparation of this black phosphorus-like two-dimensional phosphorus-based new structure also provides new ideas for the development of two-dimensional materials. The research work was supported by the National Natural Science Foundation of China, the Youth Innovation Promotion Association of the Chinese Academy of Sciences, the Frontier Science Key Research Program of the Chinese Academy of Sciences, the China Postdoctoral Science Foundation, and Shenzhen Science and Technology Research Grants.