Metal–Organic Frameworks-Derived Hierarchical Co₃O₄ Structures as Efficient Sensing Materials for Acetone Detection

Abstract

Highly sensitive and stable gas sensors have attracted much attention because they are the key to innovations in the fields of environment, health, energy savings and security, etc. Sensing materials, which influence the practical sensing performance, are the crucial parts for gas sensors. Metal-organic frameworks (MOFs) are considered as alluring sensing materials for gas sensors because of the possession of high specific surface area, unique morphology, abundant metal sites, and functional linkers. Herein, four kinds of porous hierarchical CoO structures have been selectively controlled by optimizing the thermal decomposition (temperature, rate, and atmosphere) using ZIF-67 as precursor that was obtained from coprecipitation method with the co-assistance of cobalt salt and 2-methylimidazole in the solution of methanol. These hierarchical CoO structures, with controllable cross-linked channels, meso-/micropores, and adjustable surface area, are efficient catalytic materials for gas sensing. Benefits from structural advantages, core-shell, and porous core-shell CoO exhibit enhanced sensing performance compared to those of porous popcorn and nanoparticle CoO to acetone gas. These novel MOF-templated CoO hierarchical structures are so fantastic that they can be expected to be efficient sensing materials for development of low-temperature operating gas sensors.

High‐performance flexible sensing devices based on polyaniline/MXene nanocomposites

“…We have also compared the sensitivity to ethanol of PANI‐based sensors with Ti 3 C 2 T x ‐based and PANI/Ti 3 C 2 T x ‐based sensors, and the result is shown in Figure S7. Generally, fast response and recovery rates are key parameter for sensor to real‐time usage . The transient response curves of PANI/Ti 3 C 2 T x ‐based flexible sensors to 150 ppm of ethanol gas molecules displayed rapid response and recovery time ( T res / T recov : 90% of the total current increase/decrease) of 0.4/0.5 second (Figure D).…”

Metal‐Organic‐Framework‐Derived MCo2O4 (M=Mn and Zn) Nanosheet Arrays on Carbon Cloth as Integrated Anodes for Energy Storage Applications

“…To assemble into energy storage devices, these powders should be mixed with polymer binders and conductive carbon black and then coated onto the current collectors, which usually caused the increase of interfacial impedance and the detachment of active materials from current collector. Thus, directly growing the MCo 2 O 4 materials on current collectors as integrated electrode can effectively resolve this serious issue due to several advantages including tight electrical contact with substrates, facile diffusion of electrolyte, enlarged electrode‐electrolyte contact area and adequate electrochemical reaction of each nanostructures …”

“…[1][2][3] Many kinds of meso-or microporous compounds such as carbonaceous materials, metal oxides, and metal phosphides have already been prepared by using MOFs structure as template or precursor from various processes. [4][5][6][7][8] Compared with common materials prepared from traditional solid state or chemical liquid methods, these porous compounds derived from MOFs template have evidently improved advantages including regular porosity size, large specific surface area, topological diversity and shearing ability, leading to their worldwide applications in gas storage and separation, light capture, energy conversion and storage devices, catalysis and chemical sensor and so on. [9][10][11] Spinel structured cobalt-based oxides have been extensively investigated as alternative anode materials for electrochemical energy storage devices such as supercapacitors (SCs) and lithium ion batteries (LIBs).…”

“…Thus, directly growing the MCo 2 O 4 materials on current collectors as integrated electrode can effectively resolve this serious issue due to several advantages including tight electrical contact with substrates, facile diffusion of electrolyte, enlarged electrode-electrolyte contact area and adequate electrochemical reaction of each nanostructures. [5] Herein, cobaltates MCo 2 O 4 (M=Mn and Zn) nanosheet arrays were directly grown onto carbon cloth substrates from the MOFs-assisted hydrothermal and subsequent calcination processes. When applied as electrode materials for supercapacitors and LIBs, both compounds exhibited significant improved electrochemical performance such as high specific capacitance, good rate capability, and excellent cyclic stability.…”

Highly Sensitive Acetone Gas Sensor Based on g-C3N4 Decorated MgFe2O4 Porous Microspheres Composites

“…Thus, MOS-based gas sensors have been regarded as an important method of monitoring flammable and toxic gases. Up to now, several types of MOSs have been developed as gas-sensing materials to detect acetone, such as In 2 O 3 [7], WO 3 [8,9], SnO 2 [10], La 2 O 3 [11], Co 3 O 4 [12], ZnO [13], α-Fe 2 O 3 [14] and so on. However, the gas-sensing materials have limited properties, some of which are unable to satisfy the needs of practical applications.…”