Polyol-Mediated Coprecipitation and Aminosilane Grafting of Superparamagnetic, Spinel ZnFe₂O₄ Nanoparticles for Room-Temperature Ethanol Sensors

Abstract

A simple wet-chemical procedure is reported for synthesis and subsequent functionalization of spinel ZnFe 2 O 4 nanomaterials for sensitive electrical detection of ethanol. ZnFe 2 O 4 nanoparticles are produced by triethylene glycol-mediated coprecipitation of ZnSO 4 and FeSO 4 sols in aqueous ammonia. The mechanism for synthesis is described. As-prepared ZnFe 2 O 4 nanoparticles are either thermally-treated at 673 K for 4 h or surface-modified with 3-(triethoxysilyl)propylamine to study the structure-property-sensing relationships. Fourier transform infrared spectroscopy is used to characterize functional groups on ZnFe 2 O 4 surface. X-ray diffraction analysis of thermally-treated and surface-modified ZnFe 2 O 4 nanoparticles coincide with the cubic spinel ZnFe 2 O 4 structure having a crystallite size of 4.8 nm and 5.9 nm, respectively. The microstructure of ZnFe 2 O 4 nanoparticles demonstrates a significant difference in the surface morphology of different samples. Vibrating sample magnetometer analyses demonstrate that ZnFe 2 O 4 nanoparticles are superparamagnetic in nature. Thick-film chemiresistive ethanol sensors are then fabricated and tested at 300 K to determine the sensing characteristics of different ZnFe 2 O 4 nanoparticles. The surface-modified ZnFe 2 O 4 nanoparticles exhibit the highest sensitivity (0.51 ppm −1 ), good selectivity with 168.2% (2.7 times) higher response toward ethanol compared to major interferents, fast response (τ res = 50 s) and recovery (τ rec = 116 s) times, and excellent stability with 91.5% efficiency after three weeks of testing.

Development of Feasible and Economic Electrochemical Sensor Based on Manganese Ferrite Nanoparticles (Mn0.2Fe2.8O4) for Determination of a Platelet Aggregation Inhibitor Ticagrelor Drug in Formulations and Human Blood

“…Techniques such as sol-gel, coprecipitation, mechanochemical processing, microemulsion and microwaves have been commonly used to prepare ferrite nanoparticles. [37][38][39][40] But, until now, the most economical way for the production of large quantities of ferrite NPs is chemical co-precipitation due to its advantages such as using inorganic reactants, cheap synthetic process, simple, high yield product with superior magnetic and crystal properties.…”

LaF3 Doped Co3O4 Mesoporous Nanomaterials with Hierarchical Structure for Enhanced Triethylamine Gas Sensing Performances

“…Gas sensing mechanism.-The gas sensing mechanism of Co 3 O 4 is widely believed to be a result of the change of electrical conductivity caused by the interaction between the gas molecules and the surface adsorbed O 2 , which involves gas adsorption, surface reaction, and gas desorption processes. [49][50][51] The enhanced sensing performance of the La-Co The schematic of the TEA gas sensing mechanism based on the La-Co 3 O 4 sensors is shown in Scheme 1.…”

Fabrication, mechanical, and electromagnetic studies of cobalt ferrite based‐epoxy nanocomposites

“…The magnetization of the particles may reduce at high temperatures, due to (a) the cobalt may diminish from the system at high temperature (ie, at 420°C; the melting point of Co), thus decreasing the size of nanoparticles and the small size nanoparticles have a large value of Ms. (b) the amount of hydroxyl and subsequently oxidation level of Fe may reduce, behaving as pure 3‐APTES has been placed on the surface of annealed CoFe 2 O 4 ; this smooths the surface of nanoparticles without affecting the magnetic properties, as reflected by the sound free M‐H loop. [ 42 ]…”

“…The first major weight loss was recorded to start at 300 to 350°C that may be attributed to the decomposition of the stabilizing agent. [ 42,43 ] For EP‐CoFe 2 O 4 nanocomposites, it was the major weight loss. For neat epoxy resin, the degradation of polymeric materials was initiated at the same temperature (300‐350°C) where the decomposition corresponded to 10% weight loss.…”