Large-lateral-area SnO nanosheets with a loose structure for high-performance acetone sensor at the ppt level.

Gas sensors with high sensitivity and high selectivity are required in practical applications to distinguish between target molecules in the detection of volatile organic compounds, real-time security alerts, and clinical diagnostics. Semiconducting tin oxide (SnO) is highly regarded as a gas-sensing material due to its exceptional responsiveness to changes in gaseous environments and outstanding chemical stability. Herein, we successfully synthesized a large-lateral-area SnO nanosheet with a loose structure as a gas sensing material by a one-step facile aqueous solution process without a surfactant or template.

Facet-Controlled Synthesis of CeO Nanoparticles for High-Performance CeO Nanoparticle/SnO Nanosheet Hybrid Gas Sensors.

CeO nanocubes with metastable {100} facets and CeO nanooctahedrons with the most stable {111} facets are herein fabricated by controlling the morphology and facets of CeO nanoparticles. SnO nanosheet-based assembled films coated with these CeO nanocubes or CeO nanooctahedrons yield {100} CeO nanocubes/SnO nanosheets and {111} CeO nanooctahedron/SnO nanosheet hybrid gas sensors, respectively. The hybrid sensors with CeO nanoparticles exhibited enhanced sensing responses to numerous chemical species relative to a pristine SnO nanosheet gas sensor, including acetone, hydrogen, ethanol, ammonia, acetaldehyde, and allyl mercaptan.

Nanosheet-type tin oxide gas sensor array for mental stress monitoring.

Mental stress management has become significantly important because excessive and sustained mental stress can damage human health. In recent years, various biomarkers associated with mental stress have been identified. One such biomarker is allyl mercaptan.

Highly Sensitive and Selective Gas Sensors Based on NiO/MnO @NiO Nanosheets to Detect Allyl Mercaptan Gas Released by Humans under Psychological Stress.

NiO nanosheets are synthesized in situ on gas sensor chips using a facile solvothermal method. These NiO nanosheets are then used as gas sensors to analyze allyl mercaptan (AM) gas, an exhaled biomarker of psychological stress. Additionally, MnO nanosheets are synthesized onto the surfaces of the NiO nanosheets to enhance the gas-sensing performance.

Facile synthesis of ZnO nanobullets by solution plasma without chemical additives.

ZnO nano-bullets were synthesized using solution plasma from only Zn electrode in water without any chemical agents. In this sustainable synthesis system, the rapid quenching reaction at the interface between the plasma/liquid phases facilitates the fast formation of nano-sized materials. The coil-to-pin type electrode geometry, which overcomes the discharge interruption owing to the electrode gap broadening of the typical pin-to-pin type enables the synthesis of numerous nanomaterials through a stable discharge for 1 h.

Self-Adaptive Gas Sensor System Based on Operating Conditions Using Data Prediction.

Through the improvement of nanomaterial technologies, a gas sensor was developed for detecting ppm or ppb levels of gas. Our SnO nanosheet gas sensor can detect 50 ppb of acetone without the requirement of a novel metal catalyst by exposing the (101) facet containing the Sn state. Despite the high performance, the fluctuation of the gas response value based on operating conditions, even at the same concentration, is a critical problem in gas sensors.

Catalyst-free Highly Sensitive SnO Nanosheet Gas Sensors for Parts per Billion-Level Detection of Acetone.

The development of a facile gas sensor for the ppb-level detection of acetone is required for realizing health diagnosis systems that utilize human breath. Controlling the crystal facet of a nanomaterial is an effective strategy to fabricate a high-response gas sensor without a novel metal catalyst. Herein, we successfully synthesized a SnO nanosheet structure, with mainly exposed (101) crystal facets, using a SnF aqueous solution at 90 °C.

Effect of Crystal Defect on Gas Sensing Properties of CoO Nanoparticles.

Crystal growth-controlled CoO nanoparticles were prepared to examine gas sensing properties. A cube-like, an irregular shaped, and three kinds of raspberry-type structures were observed by morphology analysis. The raspberry-type structures have an expanded lattice volume with a large oxygen deficiency area, and the cube-like structure has a contracted lattice volume as compared to the irregular shaped structure.

Fabrication and H-Sensing Properties of SnO Nanosheet Gas Sensors.

Vertically formed and well-defined SnO nanosheets are easy to fabricate, involving only a single process that is performed under moderate conditions. In this study, two different sizes of a SnO nanosheet were concurrently formed on a Pt interdigitated electrode chip, with interconnections between the two. As the SnO nanosheets were grown over time, the interconnections became stronger.

Catalytic Liquid-Phase Oxidation of Phenolic Compounds Using Ceria-Zirconia Based Catalysts.

Catalytic liquid-phase oxidation using a catalyst and oxygen gas (Catalytic wet air oxidation, CWAO) is one of the most promising technology to remove hazardous organic compounds in wastewater. Up to now, various heterogeneous catalysts have been reported for phenolic compounds decomposition. The CeO-ZrO based catalysts have been recently studied, because CeO-ZrO works as a promoter which supplies active oxygen species from inside the lattice to the active sites.

Catalytic liquid-phase oxidation of acetaldehyde to acetic acid over a Pt/CeO2-ZrO2-SnO2/γ-alumina catalyst.

Pt/CeO2-ZrO2-SnO2/γ-Al2O3 catalysts were prepared by co-precipitation and wet impregnation methods for catalytic oxidation of acetaldehyde to acetic acid in water. In the present catalysts, Pt and CeO2-ZrO2-SnO2 were successfully dispersed on the γ-Al2O3 support. Dependences of platinum content and reaction time on the selective oxidation of acetaldehyde to acetic acid were investigated to optimize the reaction conditions for obtaining both high acetaldehyde conversion and highest selectivity to acetic acid.

Functional characterization of OsRacB GTPase--a potentially negative regulator of basal disease resistance in rice.

The rice genome contains at least seven expressed Rop small GTPase genes. Of these Rops, OsRac1 is the only characterized gene that has been implicated in disease resistance as a positive regulator. To our interest in finding a negative ROP regulator of disease resistance in rice, we applied a "phylogeny of function" approach to rice Rops, and identified OsRacB based on its close genetic orthologous relationship with the barley HvRacB gene, a known negative regulator of disease resistance.