The ultrafine amorphous-nanocrystalline duplex structure realizes the excellent azo dye degradation characteristics of metal glass

Amorphous alloys with disordered atomic packing arrangements and metastable energy states exhibit unique mechanical, physical, and chemical behaviors such as high strength, strong corrosion resistance, and high surface activity. The wide adjustability of the composition and structure of amorphous alloys provides a variety of possible ways to further improve the physical and chemical properties, making amorphous alloys have broad application prospects in the field of catalysis. Among them, iron-based amorphous alloys have significant catalytic efficiency in the degradation of azo dyes. Due to the synergistic advantages of crystalline and amorphous phases, catalytic performance can be further improved by introducing additional crystalline phases into the amorphous matrix. However, the grains generated by traditional amorphous-crystalline composites induced by fast cooling and annealing are easy to coarserate, resulting in insufficient amorphous-crystal interface, which limits synergy and galvanic cell effects, and inhibits the greatly improved catalytic efficiency. Moreover, the above method of adjusting the temperature and time window is narrow, and the microstructure and catalytic performance of amorphous alloys cannot be effectively adjusted. Through the controlled deposition method, we can adjust the deposition parameters and surface diffusion behavior in a targeted manner, and obtain amorphous thin films with different microstructures and energy states.

Recently, Bai Haiyang and Lu Zhen, a researcher in the amorphous team of the Institute of Physics, Chinese Academy of Sciences/Beijing National Research Center for Condensed Matter Physics, supervised Peng Xinjie, a doctoral student at the Institute of Physics, to prepare Fe76Si8B13Nb3 amorphous films with in-situ growth nanoscale amplitude-modulated decomposition duplex structure by ion beam deposition (IBD) rapid surface diffusion method, and obtained 2 × 1016 by subsequent high-temperature annealing Amorphous-crystalline duplex structure at the m-2 high concentration interface where the grain size is less than 5 nm (Figure 1). The ultrafine amorphous-crystalline Fe76Si8B13Nb3 film designed for targeted display excellent degradation performance (Figure 2), and the degradation efficiency of azo dyes is 300 times that of commercial iron powder. The high degradation efficiency of amorphous-crystalline catalysts can be attributed to the synergistic effect of nanocrystalline and amorphous matrix to promote the formation of galvanic cells, while the low resistivity of the crystalline phase accelerates electron transport, and the rich phase interface increases the intrinsic enhancement active site (Figure 3). Unlike previous reports, amorphous-crystalline composites exhibit excellent catalytic performance without hydrogen peroxide assistance, providing environmentally friendly neutral reaction conditions and avoiding corrosion damage to containers during commercial wastewater treatment. This work not only demonstrates the potential of structure-controllable amorphous alloys in catalytic applications, but more importantly, provides a new approach for the design and development of ultrafine amorphous-crystal composite catalytic materials by nanoscale phase separation precursors.

Figure 1: Microstructure characterization of amorphous films and amorphous-nanocrystalline films.

Fig. 2 Comparison of dye degradation performance (excluding Fenton-like reactions).

Figure 3 Schematic diagram of degradation mechanism.

The related research results, titled “Unexpected enhanced catalytic performance via highly dense interfaces in ultra-fine amorphous-nanocrystalline biphasic structure”, were published online in Applied Materials on November 19, 2022 Today on. Researcher Bai Haiyang and Lu Zhen are the co-corresponding authors of the paper, and Peng Xinjie is the first author of the paper. This research has been strongly supported by the National Key Research and Development Program of China (2021YFB3802900), the National Natural Science Foundation of China (52192600, 952192601), and the Huairou Material Genome of the Institute of Physics. (Source: Institute of Physics, Chinese Academy of Sciences)

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