Gas Sensing Properties of p-Co3O4/n-TiO2 Nanotube Heterostructures

Abstract

In this paper, we fabricated p-Co3O4/n-TiO2 heterostructures and investigated their gas sensing properties. The structural and morphological characterization were performed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy analysis (XPS). The electrical properties of the heterostructure were studied within the temperature range from 293 K to 423 K. Changes in electrical properties and sensing behavior against reducing and oxidizing gases were attributed to the formation of p–n heterojunctions at the Co3O4 and TiO2 interface. In comparison with sensing performed with pristine TiO2 nanotubes (NTs), a significant improvement in H2 sensing at 200 °C was observed, while the sensing response against NO2 decreased for the heterostructures. Additionally, a response against toluene gas, in contrast to pristine TiO2 NTs, appeared in the Co3O4/TiO2 heterostructure samples.

Enhanced ethanol sensing properties of WO3 modified TiO2 nanorods

“…Among all these techniques, semiconductor metal oxide (SMO) based chemi -resistive gas sensors are one of the best candidates due to their high sensitivity and easy production processes [14][15][16]. Moreover, different techniques such as loading with catalyst, doping a host element or heterostructural fabrication of SMO materials may improve their gas sensing properties against various gas species [17][18][19][20][21][22]. Therefore, SMOs are superior sensing materials for VOCs detection.…”

“…The sensing performances of heterojunction enhances in virtue of band alteration at the interface between different materials. This provides charge transfer through interface from one material to another by creating charge-space region and adsorption sites [17,[28][29][30][31][32]. WO 3 is one of the best candidates for heterostructure due to its highly reactive nature against various VOCs [33,34].…”

The Analysis of the Urea Biosensors Using Different Sensing Matrices via Wireless Measurement System & Microfluidic Measurement System

“…Additionally, it can also help maintain the biocatalytic activity of enzymes [7]. TiO 2 showed significant promise in surface tests for the immobilization of biomolecules, therefore, recently increased research has been devoted to it [8,9,10,11,12,13]. The above researches all demonstrate that NiO and TiO 2 are promising materials when they are used as sensing matrices.…”

A New Calibration Circuit Design to Reduce Drift Effect of RuO2 Urea Biosensors

“…The NiO has strong chemical stability and fast electron transfer capability; therefore, it is also applied as a sensing material to develop uric and glucose sensors [1,5,6,7]. TiO 2 is a non-toxic, non-corrosive, and reusable material with better electron transition, making it a good sensing film material for biosensors [8,9,10,11,12]. Ruthenium oxide (RuO 2 ) is a transition metal oxide with rutile-type structure and high metallic conductivity; RuO 2 is a suitable material for working electrodes due to its low resistivity, high thermal stability, and good diffusion barrier properties [28,29,30,31].…”

“…Although different urea biosensors had been widely studied to achieve better sensing characteristics [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25], the non-ideal effects and drift rates had been barely discussed in previous works. Chou et al [24] presented a flexible arrayed urea sensor based on urease-magnetic beads (MBs) and graphene oxide (GO), but it was only able to measure the drift rate and the drift effect calibration method was not discussed.…”