Humidity sensing application of CeO2 nanoparticles: mechanism interpretation with density functional theory

IF 4.9 Q1 CHEMISTRY, ANALYTICAL

Sensing and Bio-Sensing Research Pub Date : 2025-09-01 DOI:10.1016/j.sbsr.2025.100872

M.V. Arularasu , V. Vetrivelan , A. Muthukrishnaraj , Manikandan Ayyar , D.S. Vijayan , S. Sathiyamurthy , Prabhu Paramasivam , Sandeep Kumar , Gaurav Kumar

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引用次数: 0

Abstract

Humidity sensors play a crucial role in non-contact measurements, particularly in environmental monitoring and healthcare systems. Among various materials, semiconductor metal oxides have gained significant attention due to their favorable physicochemical and electrical properties, making them ideal candidates for humidity sensing applications. In this study, cerium oxide (CeO₂) nanoparticles (NPs) were synthesized via a green synthesis route using Morinda tinctoria leaf extract, inspired by biomimetic processes. Comprehensive characterization techniques-including X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and UV–Vis spectroscopy-were employed to evaluate the structural, functional, morphological, elemental, and optical features of the synthesized NPs. XRD confirmed the formation of pure, crystalline CeO₂ in the cubic phase without any metallic Ce impurities. Microscopy revealed a porous morphology, contributing significantly to the enhanced humidity sensing performance. The sensor exhibited high sensitivity to relative humidity (RH) across the range of 5 %–98 % at room temperature, with a resistance variation of up to 2218 Ω—demonstrating a five-order magnitude response and excellent linearity. Moreover, the sensor showed rapid response and recovery times of 23 and 44 s, respectively, along with good long-term stability. These eco-friendly and cost-effective CeO₂-based humidity sensors are well-suited for agriculture and humidity monitoring applications. To further understand the sensing mechanism, density functional theory (DFT) calculations were performed. Topological analysis using electron localization function (ELF) maps elucidated the nature of bonding in CeO₂ and its interaction with water molecules.

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CeO2纳米颗粒湿度传感应用：密度泛函理论的机理解释

湿度传感器在非接触式测量中发挥着至关重要的作用，特别是在环境监测和医疗保健系统中。在各种材料中，半导体金属氧化物由于其良好的物理化学和电学性能而获得了极大的关注，使其成为湿度传感应用的理想候选者。在本研究中，受仿生工艺的启发，以Morinda tinctoria叶提取物为原料，通过绿色合成路线合成了氧化铈（ceo2）纳米颗粒（NPs）。采用x射线衍射（XRD）、傅里叶变换红外光谱（FTIR）、场发射扫描电镜（FE-SEM）、透射电子显微镜（TEM）、能量色散x射线能谱（EDS）和紫外可见光谱等综合表征技术对合成的NPs进行了结构、功能、形态、元素和光学等方面的表征。XRD证实在立方相中形成了纯净、结晶的CeO 2，没有任何金属Ce杂质。显微镜显示多孔形态，有助于显著提高湿度传感性能。该传感器在室温下对相对湿度（RH）的灵敏度为5% - 98%，电阻变化高达2218 Ω-demonstrating，具有5个数量级的响应和良好的线性。传感器的响应时间和恢复时间分别为23 s和44 s，且具有良好的长期稳定性。这些环保且具有成本效益的基于CeO 2的湿度传感器非常适合农业和湿度监测应用。为了进一步了解传感机理，进行了密度泛函理论（DFT）计算。利用电子定位函数（ELF）图的拓扑分析阐明了ceo2中的键合性质及其与水分子的相互作用。

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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来源期刊

Sensing and Bio-Sensing Research Engineering-Electrical and Electronic Engineering

CiteScore

10.70

自引率

3.80%

发文量

审稿时长

87 days

期刊介绍： Sensing and Bio-Sensing Research is an open access journal dedicated to the research, design, development, and application of bio-sensing and sensing technologies. The editors will accept research papers, reviews, field trials, and validation studies that are of significant relevance. These submissions should describe new concepts, enhance understanding of the field, or offer insights into the practical application, manufacturing, and commercialization of bio-sensing and sensing technologies. The journal covers a wide range of topics, including sensing principles and mechanisms, new materials development for transducers and recognition components, fabrication technology, and various types of sensors such as optical, electrochemical, mass-sensitive, gas, biosensors, and more. It also includes environmental, process control, and biomedical applications, signal processing, chemometrics, optoelectronic, mechanical, thermal, and magnetic sensors, as well as interface electronics. Additionally, it covers sensor systems and applications, µTAS (Micro Total Analysis Systems), development of solid-state devices for transducing physical signals, and analytical devices incorporating biological materials.