H. Nady, Ibraheem O. Ali, Ebtsam K. Alenezy, E. E. Salama, Tarek M. Salama, Ahmed A. Elhenawy, H. H. Mohamed
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引用次数: 0
Abstract
The depletion of fossil fuels and rising global energy demand highlight the urgent need for green alternatives such as hydrogen. Developing low-cost, efficient electrocatalysts remains a key challenge for sustainable hydrogen production via water splitting. This study investigates the synthesis and electrocatalytic performance of MnFe2O4 spinel ferrite nanoparticles for the hydrogen evolution reaction (HER). The nanoparticles were synthesized via the sol-gel method and characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), Brunauer–Emmett-Teller (BET) surface area analysis, field-emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), and high-resolution transmission electron microscopy (HRTEM). XRD analysis revealed the formation of a cubic spinel structure, while ATR-FTIR spectra displayed characteristic metal-oxygen vibrational bands at 538 and 419 cm-1. XPS analysis revealed mixed oxidation states of Mn2+/Mn3+ and Fe2+/Fe3+, indicating the formation of redox-active heterojunctions that enhance catalytic performance. Morphological characterization revealed rough, interconnected clusters with a surface area of 36.63 m2/g and a pore volume of 0.088 cm3/g. EDX analysis confirmed the elemental composition of the MnFe2O4 sample. Electrochemical performance was evaluated in 1 M KOH at 25 °C using a MnFe2O4/NF electrode, which delivered a cathodic current density of 113.46 mA cm-2 at –1.5 V and required an overpotential of only 197.1 mV at 10 mA cm–2. The low overpotential and charge transfer resistance reveal the strong HER activity of MnFe2O4 and its promise as an efficient, stable electrocatalyst. Hirshfeld surface analysis and 2D fingerprint plots were employed to investigate the interatomic interactions governing crystal stability and surface topography of MnFe2O4. The results emphasize a highly stable structure, primarily driven by strong, directional Fe···O (61.7%) and Mn···O (26.5%) contacts, together contributing over 88% of the total packing interactions. The dense packing distorts FeO6 octahedra, creating concave, strained regions that act as structured binding pockets. This provides a sterically and electronically favorable environment for water adsorption and activation.
化石燃料的枯竭和全球能源需求的上升凸显了对氢等绿色替代品的迫切需求。开发低成本、高效的电催化剂仍然是通过水分解可持续制氢的关键挑战。本文研究了MnFe2O4尖晶石铁氧体纳米粒子的合成及其析氢反应（HER）的电催化性能。采用溶胶-凝胶法合成纳米颗粒，并利用x射线衍射（XRD）、x射线光电子能谱（XPS）、衰减全反射傅里叶变换红外光谱（ATR-FTIR）、布鲁诺尔-埃米特-泰勒（BET）表面积分析、场发射扫描电子显微镜（FESEM）、能量色散x射线能谱（EDS）和高分辨率透射电子显微镜（HRTEM）对其进行了表征。XRD分析表明，该材料形成了立方尖晶石结构，ATR-FTIR光谱在538和419 cm-1处显示出特有的金属-氧振动带。XPS分析显示Mn2+/Mn3+和Fe2+/Fe3+的混合氧化态，表明形成了氧化还原活性异质结，提高了催化性能。形态学表征显示，粗糙的，相互连接的簇，表面积为36.63 m2/g，孔体积为0.088 cm3/g。EDX分析证实了MnFe2O4样品的元素组成。采用MnFe2O4/NF电极，在25°C、1 M KOH条件下，在-1.5 V条件下阴极电流密度为113.46 mA cm-2，在10 mA cm-2条件下过电位仅为197.1 mV。低过电位和电荷转移电阻表明MnFe2O4具有很强的HER活性，有望成为一种高效、稳定的电催化剂。采用Hirshfeld表面分析和二维指纹图谱研究了MnFe2O4晶体稳定性和表面形貌的原子间相互作用。结果强调了一个高度稳定的结构，主要是由强的、定向的Fe··O（61.7%）和Mn··O（26.5%）接触驱动的，它们共同贡献了超过88%的填充相互作用。密集的填充物会扭曲FeO6八面体，形成凹的、紧张的区域，充当结构化的捆绑袋。这为水的吸附和活化提供了一个有利的空间和电子环境。图形抽象
期刊介绍：
The primary objective of the Journal of Sol-Gel Science and Technology (JSST), the official journal of the International Sol-Gel Society, is to provide an international forum for the dissemination of scientific, technological, and general knowledge about materials processed by chemical nanotechnologies known as the "sol-gel" process. The materials of interest include gels, gel-derived glasses, ceramics in form of nano- and micro-powders, bulk, fibres, thin films and coatings as well as more recent materials such as hybrid organic-inorganic materials and composites. Such materials exhibit a wide range of optical, electronic, magnetic, chemical, environmental, and biomedical properties and functionalities. Methods for producing sol-gel-derived materials and the industrial uses of these materials are also of great interest.
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