amorphous alloy with disordered atom stacking arrangement and metastable energy states exhibit unique mechanical, physical and chemical behaviors such as high strength, strong corrosion resistance and high surfactivity. The wide tunability of amorphous alloy composition and structure provides a variety of possible ways to further improve physical and chemical properties, making amorphous alloys have broad application prospects in the field of catalysis. Among them, , ferro-based amorphous alloy has significant catalytic efficiency in azo dye degradation. Due to the synergistic advantages of the crystal phase and the amorphous phase, the catalytic performance can be further improved by introducing additional crystal phase into the amorphous matrix.
However, the amorphous-crystal composite materials induced by traditional fast cooling and annealing are easily coarsed, resulting in insufficient interface of amorphous- crystals, limiting the synergistic and primary cell effects, and inhibiting a significant improvement in catalytic efficiency; and the above-mentioned methods adjust the temperature and time windows are narrow, and it is impossible to effectively adjust the microstructure and catalytic performance of amorphous alloys. Through the controlled deposition method, we can target the deposition parameters and surface diffusion behavior, and obtain amorphous thin film with different microstructures and energy states.
Figure 1 Microstructure characterization of amorphous films and amorphous-nano-crystalline films
Recently, Researcher Bai Haiyang and Lu Zhen from the amorphous team of the key laboratory of extreme conditions physics in Beijing National Research Center for Condensed Matt Physics, Beijing, and special researcher of the researcher of the special conditions of the amorphous film, guided the Institute of Physics, Peng Xinjie and others to use ion beam deposition (IBD) Amorphous thin film with in-situ growth nanoscale amplitude decomposition biphasic structure was prepared, and an amorphous-crystal biphasic structure with a high concentration interface of 2×1016 m-2 was obtained by subsequent high-temperature annealing, where the size of grain is less than 5 nm (Fig. 1).
Figure 2 Comparison of dye degradation performance (excluding Fenton reaction)
targeted ultrafine amorphous-crystalline Fe76Si8B13Nb3 films designed specifically show excellent degradation performance (Figure 2), and the degradation efficiency of azo dye is 300 times that of commercial iron powder. The high degradation efficiency of amorphous-crystal catalysts can be attributed to the synergistic effect of nanocrystalline and amorphous matrix, promoting the formation of primary cell . At the same time, the low resistivity of crystal phase accelerates electron transport, and the rich phase interface increases the intrinsic enhancement active site (Figure 3).
Figure 3 Schematic diagram of the degradation mechanism
Unlike previous reports, the amorphous-crystal composite material exhibits excellent catalytic performance of without the assistance of hydrogen peroxide , providing environmentally friendly neutral reaction conditions to avoid corrosion damage to containers during commercial sewage treatment . This work in not only demonstrates the potential of structurally controlled amorphous alloys in catalytic applications, but more importantly, it provides a new way to design and develop ultrafine amorphous-crystal composite catalytic materials through nanoscale phase separation precursors.
related research results were titled "Unexpected enhanced catalytic performance via highly dense interfaces in ultra-fine amorphous-nanocrystalline biphasic structure" and were published online on Applied Materials Today on November 19, 2022. Researcher Bai Haiyang and Lu Zhen’s special researcher are co-corresponding authors of the paper, and Peng Xinjie is the first author of the paper. The research has been strongly supported by the National Key R&D Program (2021YFB3802900), the National Natural Science Foundation of major projects (52192600, 952192601) and the genome of the supra material for physics.
Source: Materials Network
