Low-Dimensional Nanostructures Based on Cobalt Oxide (Co3O4) in Chemical-Gas Sensing

Abstract

Highly sensitive, stable, low production costs, together with easy maintenance and portability, sensors are ever most demanded nowadays for monitoring and quantification of hazardous chemicals/gases in the environment. The utilization of one dimensional (1D) metal oxide nano structured chemical/gas sensors for environmental monitoring is vastly investigated because of their superior surface to volume ratio, stability, and low production costs, to provide information on the presence of chemical species. Several outstanding attempts have been pursued investigating 1D nano structures of Co3O4 over the past decades as an active material for chemical analytes detection owing to its superior catalytic effect together with its excellent stability. This article reviews the state-of-the-art of growth and characterization of Co3O4 1D nano structures and their functional characterization as chemical/gas sensors. Moreover, fundamental concepts and characteristic features, that enhance the key performances of chemical/gas sensors, are discussed. Finally, challenges and prospective for growth and fabrication of 1D Co3O4 chemical/gas sensors are discussed.

P-Type Metal Oxide Semiconductor Thin Films: Synthesis and Chemical Sensor Applications

“…Usually, in a p-type semiconductor, such as CuO, NiO, Co 3 O 4 , and Cr 2 O 3 , the acceptor level is near the valance band. Typically, the acceptor level is fully ionized (filled), leaving holes in the valance band at room temperature ( Figure 2 a) [ 15 ]. Once the metal-oxide surface is exposed to air, oxygen from the air gets adsorbed on the metal-oxide surface by trapping electrons from surface states.…”

“…Once the metal-oxide surface is exposed to air, oxygen from the air gets adsorbed on the metal-oxide surface by trapping electrons from surface states. The result is band bending and an increase in hole concentration near the interface, forming a hole-accumulating layer at the MOX surface ( Figure 2 b) [ 15 ]. This causes a decrease in the MOX resistance.…”

“…E C is the conduction-band position; E F is the Fermi-level position; Ev is the valance-band position; q is electron charge; qV S is the potential barrier. Reprinted with permission from [ 15 ].…”

Ball‐milling route to design hierarchical nanohybrid cobalt oxide structures with cellulose nanocrystals interface for supercapacitors

“…23 Co 3 O 4 is a p-type magnetic semiconductor with exact band gap energy (E g ) values calculated using the Tauc equation of 1.70-2.43 eV. 24 Cobalt oxides have a wide range of technological applications including in heterogeneous catalysis for the diminution of carbon monoxide, 25,26 carbon monoxide sensors, 27 anode materials for rechargeable lithium ion batteries, 28,29 and electrode materials for supercapacitors. [30][31][32] Recently, Akgul et al 33 utilized mechanical ball milling to afford cobalt oxide nanoparticles and analyzed its atomic structures and microstructural properties.…”

Pt/Au Nanoparticles@Co3O4 Cataluminescence Sensor for Rapid Analysis of Methyl Sec-Butyl Ether Impurity in Methyl Tert-Butyl Ether Gasoline Additive

“…In recent years, metal oxides such as WO 3 [6], ZnO [7], SnO 2 [8], and Co 3 O 4 [9] have been a common type of material used in various sensors. Owing to its good catalytic performance and low cost, Co 3 O 4 is a potential material for this application, and it has been widely studied in many fields [10][11][12]. In addition, as a p-type semiconductor material, the gas-sensing capability of Co 3 O 4 is based on the catalytic properties of its surface, and it has been widely used as a catalyst to improve the selective oxidation of various volatile organic compounds (VOCs) [9,13].…”