Hjiri Mokhtar, Algessair Saja, Dhahri Ramzi, Mirzaei Ali, Neri Giovanni
Department of Physics, College of Sciences, Imam Mohammad Ibn Saud Islamic University (IMSIU) Riyadh 11623 Saudi Arabia
Department of Physics, Faculty of Sciences and Arts, Najran University P.O. Box 1988 Najran 11001 Saudi Arabia.
RSC Adv. 2024 May 30;14(25):17526-17534. doi: 10.1039/d4ra02338b. eCollection 2024 May 28.
The synthesis techniques used for metal oxide semiconductors strongly influence their chemical, physical and gas sensing characteristics. In this context, hematite (α-FeO) nanoparticles (NPs) were synthesized using two different techniques, namely, sol-gel (named H) and Pechini sol-gel (named H). The average crystallite size and surface area were 15 nm and 76 m g and 20 nm and 57 m g for H and H, respectively. Morphological studies showed that the H material was composed of ellipsoid-shaped particles, while the H material had peanut-shaped particles with open pores and channels. The comparison between the sensing performances of H and H toward ethanol indicated H to be a better sensing material for ethanol detection. The H sensor exhibited a response of 12 toward 500 ppm ethanol at 250 °C, a fast response time of 5 s and excellent selectivity. The enhanced characteristics were mainly related to the peculiar morphology with a porous nature, which led to more gas adsorption and diffusion. In addition to shape influence, the size of NPs also has an effect on the gas sensing performance. In fact, a decrease in the crystallite size led to an increase in the surface area of the material where the gas molecule-sensing layer interaction took place. The increase in the surface area created more interaction sites, and thus the sensitivity was improved. From these results, the H sensor can be regarded as a promising candidate for ethanol detection.
用于金属氧化物半导体的合成技术强烈影响其化学、物理和气体传感特性。在此背景下，采用两种不同技术合成了赤铁矿（α-Fe₂O₃）纳米颗粒（NPs），即溶胶-凝胶法（命名为H₁）和佩琴尼溶胶-凝胶法（命名为H₂）。H₁和H₂的平均晶粒尺寸和表面积分别为15 nm和76 m²/g以及20 nm和57 m²/g。形态学研究表明，H₁材料由椭球形颗粒组成，而H₂材料具有带有开放孔隙和通道的花生形颗粒。H₁和H₂对乙醇的传感性能比较表明，H₂是用于乙醇检测的更好传感材料。H₂传感器在250℃下对500 ppm乙醇的响应为12，响应时间快至5秒且具有优异的选择性。增强的特性主要与具有多孔性质的特殊形态有关，这导致更多的气体吸附和扩散。除了形状影响外，NPs的尺寸也对气体传感性能有影响。实际上，晶粒尺寸的减小导致气体分子与传感层相互作用发生的材料表面积增加。表面积的增加产生了更多的相互作用位点，从而提高了灵敏度。从这些结果来看，H₂传感器可被视为乙醇检测的有前途的候选者。
