In this paper, the synthesis of LaFeO₃ based on the gel combustion method has been improved by using citric acid (CA) as a secondary chelating agent on glucose. The synthesized samples were calcined at 600 °C and further characterized using X-ray diffraction (XRD), Fourier transform infrared, field-emission scanning electron microscopy (FESEM), scanning electron microscopy, energy-dispersive X-ray spectrophotometry, N₂ adsorption–desorption analyses, thermogravimetric analysis, and UV–vis–near-IR spectroscopy. The XRD data revealed that the pure orthorhombic perovskite phase LaFeO₃ was obtained when CA was added on glucose. From FESEM and Brunauer–Emmett–Teller analysis, LaFeO₃ synthesized using the addition of CA on glucose potentially showed well-uniform spherical particles and a high specific surface area of 40.77 m²/g with a particle size of 70 nm compared to glucose, which only showed 15.68 m²/g with a particle size of 100–300 nm. The photocatalytic activity of LaFeO₃ was evaluated by the degradation of diazo dyes, Reactive Black 5 (RB5) under visible-light irradiation, indicating that synthesized LaFeO₃ using the addition of CA on glucose exhibited excellent adsorption efficiency and remarkable photocatalytic activity with reaction rate constant K = 0.0680 min^–1, which was higher than that of the synthesized LaFeO₃ based on glucose only with reaction rate constant K = 0.0087 min^–1.

中文翻译：

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柠檬酸添加对葡萄糖基凝胶燃烧法制备的LaFeO ₃纳米颗粒的形貌，表面积和光催化活性的影响

在本文中，通过使用柠檬酸（CA）作为葡萄糖的第二种螯合剂，改进了基于凝胶燃烧法的LaFeO ₃的合成。合成后的样品在600°C下煅烧，并使用X射线衍射（XRD），傅里叶变换红外光谱，场发射扫描电子显微镜（FESEM），扫描电子显微镜，能量色散X射线分光光度法，N ₂吸附进行进一步表征-解吸分析，热重分析和紫外-可见-近红外光谱。XRD数据表明，当在葡萄糖上添加CA时，获得了纯正交晶钙钛矿相LaFeO ₃。来自FESEM和Brunauer–Emmett–Teller分析，LaFeO ₃在葡萄糖上添加CA合成的葡萄糖可能显示均匀的球形颗粒，比表面积仅70. nm的高比表面积为40.77 m ² / g，而葡萄糖仅显示15.68 m ² / g 100-300 nm。LaFeO ₃的光催化活性通过可见光照射下重氮染料Reactive Black 5（RB5）的降解来评价，表明通过添加CA对葡萄糖合成的LaFeO ₃表现出优异的吸附效率和显着的光催化活性，且反应速率高。常数K = 0.0680 min ^–1，比合成的LaFeO _3高仅基于葡萄糖，反应速率常数K = 0.0087 min ^–1。