Physicochemical properties of rGO-LaFeO3 microspheres tailored by solvents and calcination temperature

Next Materials Pub Date : 2025-07-23 DOI:10.1016/j.nxmate.2025.100985

Neeru Sharma , Kirti Bhardwaj , Pashupati Pratap Neelratan , Sanjeev Kumar Sharma

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Abstract

This study investigates the influence of solvents and calcination on the structural and morphological properties of rGO-LaFeO₃ composites by a one-step hydrothermal approach using two precursors: C₆H₈O₇ and KOH, then calcined at 800 °C for 2–6 h. Microstructural analysis confirmed that citric acid-assisted composites formed microspheres, while KOH-assisted composites exhibited mixed morphology and structures. EDAX and XPS give the elemental/chemical compositions for both products. The XRD pattern revealed a higher degree of crystallization with a decrease in lattice strain and dislocation density under calcination. Dislocation density and lattice strain were found 21.0 × 10⁻³ cm⁻³ and 5.2 × 10⁻² respectively for rGO-LaFeO₃ (C₆H₈O₇), while it becoming lesser as 4.8 × 10⁻³ cm⁻³ and 2.4 × 10⁻² for rGO-LaFeO₃ (KOH) under calcinations (800 ℃) for duration of 6 h. FT-IR and Raman spectra further confirmed the presence of the Fe-O phase. Before calcinations, the higher surface area was obtained for the composite using KOH (82.40 m²/g), while a decline in the surface area of the composite was observed using C₆H₈O₇ (40.21 m²/g) under calcinations for 6 h. UV-Vis investigates a tunable bandgap, with rGO-LaFeO₃ (KOH) maintaining a lower bandgap (∼2.03 eV) than rGO-LaFeO₃ (C₆H₈O₇) (∼2.26 eV) without calcination, while becoming wider (∼2.34 eV) under calcination for 6 h. A higher degree of crystallization of rGO-LaFeO₃ (KOH) under calcinations causes a wider bandgap, enables charge carrier transport, and marks the composite as an n-type material. The findings, higher surface area (82.40 m²/gm), lower bandgap (∼2.03 eV), and larger crystallite size (14.5 Å) highlight tailored physicochemical properties of rGO-LaFeO₃ (KOH) and make it a more promising material than citric-acid derived composite to give better performance for gas sensing toward NO₂ gas.

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溶剂和煅烧温度对rGO-LaFeO3微球理化性质的影响

本研究采用C6H8O7和KOH两种前驱体，在800℃下煅烧2-6 h，采用一步水热法研究了溶剂和煅烧对rGO-LaFeO3复合材料结构和形态性能的影响。微观结构分析证实，柠檬酸辅助复合材料形成微球，而氢氧化钾辅助复合材料呈现混合形态和结构。EDAX和XPS给出了两种产品的元素/化学组成。XRD谱图显示，煅烧过程中晶体的结晶程度较高，晶格应变和位错密度减小。位错密度和晶格应变被发现21.0 × 10−3厘米−3和5.2 × 10−2分别为rGO-LaFeO3 (C6H8O7),虽然它成为小4.8 × 10−3厘米−3和2.4 × 10−2 rGO-LaFeO3 (KOH)段烧(800 ℃)持续时间6 h。FT-IR和拉曼光谱进一步证实了Fe-O相的存在。煅烧前，使用KOH可获得较高的比表面积（82.40 m2/g），而使用C6H8O7（40.21 m2/g）在煅烧6 h后，复合材料的比表面积有所下降。UV-Vis研究了一个可调谐的带隙，rGO-LaFeO3 （KOH）在没有煅烧的情况下保持比rGO-LaFeO3 (C6H8O7)（~ 2.26 eV）更低的带隙（~ 2.03 eV），而在煅烧6 h时变得更宽（~ 2.34 eV）。rGO-LaFeO₃（KOH）在煅烧过程中较高的结晶程度导致更宽的带隙，使载流子能够传输，并标志着该复合材料为n型材料。研究结果表明，更高的表面积（82.40 m2/gm）、更低的带隙（~ 2.03 eV）和更大的晶粒尺寸（14.5 Å）突出了rGO-LaFeO₃（KOH）的定制物理化学性质，使其成为比柠檬酸衍生复合材料更有希望对NO2气体具有更好的气感性能的材料。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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