Study for the enhanced energy storage properties of α-MoO3 microstructures in lithium ion batteries

Orthorhombic α-MoO3 is one thermodynamically multifunctional material and presents significant performance in lithium-ion batteries. It is interesting to prepare α-MoO3 structures through a facile method that can deliver a high...

Improving Gas-Sensing Performance Based on MOS Nanomaterials: A Review

In order to solve issues of air pollution, to monitor human health, and to promote agricultural production, gas sensors have been used widely. Metal oxide semiconductor (MOS) gas sensors have become an important area of research in the field of gas sensing due to their high sensitivity, quick response time, and short recovery time for NO₂, CO₂, acetone, etc. In our article, we mainly focus on the gas-sensing properties of MOS gas sensors and summarize the methods that are based on the interface effect of MOS materials and micro–nanostructures to improve their performance. These methods include noble metal modification, doping, and core-shell (C-S) nanostructure. Moreover, we also describe the mechanism of these methods to analyze the advantages and disadvantages of energy barrier modulation and electron transfer for gas adsorption. Finally, we put forward a variety of research ideas based on the above methods to improve the gas-sensing properties. Some perspectives for the development of MOS gas sensors are also discussed.

High acetone sensing properties of In2O3-NiO one-dimensional heterogeneous nanofibers based on electrospinning

Pure NiO nanofibers and the In2O3-NiO one-dimensional heterogeneous nanofibers were prepared by electrospinning, and the gas sensing properties to acetone were also investigated. Material characterization proved that the heterogeneous nanofibers were composed of In2O3 and NiO, and the nanofibers exhibited an enhanced sensitivity to acetone. At the optimal working temperature, the response of In2O3-NiO nanofibers to 50 ppm acetone was more than 10 times higher than that of pure NiO nanofibers. The minimum detection limit of the heterogeneous nanofibers reached 10 ppb, while the pure NiO nanofibers only reached 100 ppb. Among acetone and the comparison gases (methanol, ethanol, triethylamine, ethyl acetate, and benzene), the heterogeneous nanofibers achieved the highest response to acetone. In addition, the heterogeneous nanofibers exhibited an improved response-recovery rate and good long-term stability. These results indicated that the In2O3-NiO one-dimensional heterogeneous nanofibers have great potential in low-concentration acetone detection. Combined with the material properties, the mechanism of the enhanced sensing properties was discussed in detail for the In2O3-NiO heterogeneous nanofibers.

A microcube-like hierarchical heterostructure of α-Fe2O3@α-MoO3 for trimethylamine sensing

A rational design and directional synthesis of well-defined porous metal oxide heterostructures remains a challenge for the fabrication of new gas sensors with enhanced sensing properties. Herein, a novel hierarchical heterostructure of α-Fe2O3@α-MoO3 microcubes was prepared by applying a self-sacrifice template strategy, in which a porous metal-organic framework (MOF) was used as the precursor with the partial insertion of OH- and MoO42- and extraction of [Fe(CN)6]34- followed by heating treatment. Benefiting from the porous microcubic structural characteristic, the α-Fe2O3@α-MoO3 heterostructures exhibited excellent selectivity and high sensitivity for triethylamine gas with the highest response value (Ra/Rg) of 18.64 under the operating temperature of 240 °C. The experimental results also revealed that the material showed a fast response and recovery time (12 s/106 s) and excellent repeatability for at least 20 days. This feasible synthetic strategy may provide a versatile and controlled way to prepare other polymetal oxide-based heterostructures with improved sensing performance.