Design and optimization strategies of metal oxide semiconductor nanostructures for advanced formaldehyde sensors

In view of their inimitable characteristics and properties, SnO2 nanomaterials and nanocomposites have been used not only in the field of diverse advanced catalytic technologies and sensors but also in the field of energy storage such as lithium-ion batteries and supercapacitors, and in the field of energy production such as solar cells and water splitting. This review discusses the various synthesis techniques such as traditional methods, including processes like thermal decomposition, chemical vapor deposition, electrospinning, sol-gel, hydrothermal, solvothermal, and template-mediated methods and green methods, which include synthesis through plant-mediated, microbe-mediated, and biomolecule-mediated processes. Moreover, the advantages and limitations of these synthesis procedures and how to overcome them that would lead to future research are also discussed. This literature also focuses on various applications such as environmental remediation, energy production, energy storage, and removal of biological contaminants. Therefore, the rise and journey of SnO2-based nanocomposites will motivate the modern generation of chemists to modify and design robust nanoparticles and nanocomposites that can effectively tackle significant environmental challenges. This overview concludes by providing future perspectives on research into tin oxide in synthesis and its various applications.

Tin oxide based nanostructured materials: synthesis and potential applications.

Peroxymonosulfate activation by Co3O4/SnO2 for efficient degradation of ofloxacin under visible light.

Rapid detection of hazardous trace gas is critical to protect humans from health threats. The current gas sensors, however, suffer from insufficient sensitivity and selectivity, which limits their use in the application of real-time monitoring for low concentration gas. Herein, a versatile “in situ enrichment amplification” (IEA) strategy is proposed, aiming to integrate the in situ formed adsorption-functional material for target gas enrichment and the backbone sensor-functional material for gas response. The IEA-based gas sensors exhibit high sensitivity and selectivity toward the detection of HCHO gas. The calculated detection limit of the IEA sensor to HCHO gas is 63 ppb, much lower than that of the conventional HCHO sensor (183 ppb). Furthermore, a wireless cloud HCHO detection system is developed to achieve sustainable remote monitoring of the HCHO gas. Application of this IEA strategy to other metal oxide sensing materials generates similarly successful results. A feasible “in situ enrichment amplification” (IEA) strategy is proposed, aiming to integrate the adsorption-functional material for target gas enrichment and the sensor-functional material for gas sensing reaction. As a result, the IEA-based gas sensor delivers high sensitivity with a response value of 23.7 towards 100 ppm HCHO, low detection limits (63 ppb), and sound selectivity. Furthermore, a wireless cloud HCHO detection system is developed to achieve sustainable remote monitoring of the HCHO gas. • An “in situ enrichment amplification” gas sensing strategy was proposed, which integrated the adsorption-functional material for gas enrichment and the sensor-functional material for gas response. • The IEA-based gas sensors deliver high sensitivity and low detection limits (63 ppb) to HCHO gas. • The wireless cloud HCHO detection (CHD) system based on IEA-based gas sensor demonstrates sustainable monitoring and early warning of HCHO gas. 

In situ enrichment amplification strategy enabling highly sensitive formaldehyde gas sensor

Metal oxide semiconductor (MOS) nanostructures have been widely explored for formaldehyde sensors. The low surface chemical and electronic properties of pure MOS, however, greatly limits the sensor functions. In this work, Fe2O3-sensitized SnO2 nanosheets are designed via atomic layer deposition (ALD) to realize high performance formaldehyde detection. By varying the ALD cycles, the influence of different Fe2O3 loading on the sensing performance of SnO2 nanosheets is revealed. It is found that Fe2O3 ALD can greatly boost the sensing performance and the SnO2 nanosheets with 20 Fe2O3 ALD cycles exhibits the best response (Ra/Rg = 4.5) and fast response and recovery dynamics (9 and 34 s) to 20 ppm formaldehyde at a relative low temperature of 220 °C. The sensor based on SnO2/Fe2O3 also displays good selectivity to formaldehyde as well as the reliable stability and low limit of detection (LOD). This work will shed some light to design efficient MOS heterostructures for detection of formaldehyde.

Fe2O3-sensitized SnO2 nanosheets via atomic layer deposition for sensitive formaldehyde detection

The sublethal effects of pesticide poisoning will have significant negative impacts on the foraging and learning of bees and bumblebees, so it has received widespread attention. However, little is known about the physiological effects of sublethal spinetoram and glyphosate exposure on bumblebees. We continuously exposed Bombus terrestris to sublethal (2.5 mg/L) spinetoram or glyphosate under controlled conditions for 10 days. The superoxide dismutase, glutathione-S-transferase, carboxylesterase, prophenoloxidase, α-amylase and protease activities, and changes in gut microbes were measured to understand the effects of sublethal pesticide exposure on the physiology and gut microbes of bumblebees. Sublethal pesticide exposure to significantly increased superoxide dismutase activity and significantly decreased gut α-amylase activity in bumblebees but had no significant effect on glutathione-S-transferase, carboxylesterase or gut protease activities. In addition, glyphosate increased the activity of prophenoloxidase. Interestingly, we observed that neither of the two pesticides had a significant effect on dominant gut bacteria, but glyphosate significantly altered the structure of the dominant gut fungal community, and reduced the relative abundance of Zygosaccharomyces associated with fat accumulation. These results suggest that sublethal spinetoram and glyphosate do not significantly affect the detoxification system of bumblebees, but may affect bumblebee health by inhibiting energy acquisition. Our results provide information on the sublethal effects of exposure to low concentrations of glyphosate and spinetoram on bumblebees in terms of physiology and gut microbes.

/pdf/effects-of-spinetoram-and-glyphosate-on-physiological-3v4kta4m.pdf

Qianxiong Huang

Papers

Fe2O3-sensitized SnO2 nanosheets via atomic layer deposition for sensitive formaldehyde detection

Effects of spinetoram and glyphosate on physiological biomarkers and gut microbes in Bombus terrestris