Search Results (4)

This study reports, for the first time, the utilization of two-dimensional (2D) tellurium (Te) nanosheets for the efficient nonenzymatic detection of hydrogen peroxide (H₂O₂). H₂O₂ acts as a pivotal biomarker with widespread applications across environmental, biological, industrial, and food processing domains. However, an excessive accumulation of H₂O₂ in the body poses a severe threat to human life. Consequently, the imperative need for a selective, sensitive, and cost-effective sensing platform for H₂O₂ detection has gained paramount significance. Employing a low-cost and straightforward hydrothermal method, Te nanosheets were synthesized to address the escalating demand for a reliable detection platform. The as-synthesized Te nanosheets are characterized through Raman spectroscopy and atomic force microscopy techniques. The electrochemical performance of the Te nanosheets integrated onto a glassy carbon (Te-GC) electrode was thoroughly investigated using cyclic voltammetry, differential pulse voltammetry, and chronoamperometry. The experiments were designed to evaluate the response of the Te-GC electrode in the presence and absence of H₂O₂, alongside its performance in the detection of other pertinent interfering analytes. The sensor shows a limit of detection of 0.47 µM and a sensitivity of 27.2 µA µM⁻¹ cm⁻² towards H₂O₂. The outcomes of this study demonstrate the efficacy of Te nanosheets as a promising material for nonenzymatic H₂O₂ detection in urine samples. The simplicity and cost-effectiveness of the hydrothermal synthesis process, coupled with the notable electrochemical performance of the Te/GC electrode, highlight the potential of Te nanosheets in the development of a robust sensing platform. This research contributes to the ongoing efforts to enhance our capabilities in monitoring and detecting H₂O₂, fostering advancements in environmental, biomedical, and industrial applications. Full article

Telluriums (Te) with various nanostructures, including particles, wires, and sheets, are controllably synthesized by adjusting the content of polyvinylpyrrolidone (PVP) in a facile solvothermal reaction. Te nanostructures all have complete grain sizes with excellent crystallinity and mesopore structures. Further, the formation mechanisms of Te nanostructures are proposed to be that the primary nuclei of Te are released from the reduction of TeO₃²⁻ using N₂H₄·H₂O, and then grow into various nanostructures depending on the different content of PVP. These nanostructures of Te all exhibit the photocatalytic activities for the degradation of MB and H₂ production under visible light irradiation, especially Te nanosheets, which have the highest efficiencies of degradation (99.8%) and mineralization (65.5%) at 120 min. In addition, compared with pure Te nanosheets, the rate of H₂ production increases from 412 to 795 μmol∙h⁻¹∙g⁻¹ after the introduction of Pt, which increases the output by nearly two times. The above investigations indicate that Te with various nanostructures is a potential photocatalyst in the field of degradation of organic pollutants and H₂ fuel cells. Full article

Symmetry-deficient two-dimensional (2D) layered materials induce a highly anisotropic optical response due to the anisotropy in their crystal structure, facilitating their application in polarized nanodevices. Intercalation is a new way to tune the optoelectronic properties of materials by inserting guest atoms into layered host materials, and 2D layered structures stacked with van der Waals gaps are a prerequisite for this phase of the technique. In this paper, 2D tellurium nanosheets were synthesized with a hydrothermal method, and copper atoms were inserted with a wet chemical method. The widening of the crystal plane spacing proves the introduction of copper atoms, and polarization−related second-harmonic-generation (SHG) studies reveal the intrinsic anisotropic modes of the two samples, and birefringent properties are found with polarizing light microscopy. We further investigated the electrical properties of the samples, and the embedding of the copper atoms caused the samples to exhibit higher currents, but their devices lost the gate control effect. Full article

The cost-effective conversion of low-grade heat into electricity using thermoelectric devices requires developing alternative materials and material processing technologies able to reduce the currently high device manufacturing costs. In this direction, thermoelectric materials that do not rely on rare or toxic elements such as tellurium or lead need to be produced using high-throughput technologies not involving high temperatures and long processes. Bi₂Se₃ is an obvious possible Te-free alternative to Bi₂Te₃ for ambient temperature thermoelectric applications, but its performance is still low for practical applications, and additional efforts toward finding proper dopants are required. Here, we report a scalable method to produce Bi₂Se₃ nanosheets at low synthesis temperatures. We studied the influence of different dopants on the thermoelectric properties of this material. Among the elements tested, we demonstrated that Sn doping resulted in the best performance. Sn incorporation resulted in a significant improvement to the Bi₂Se₃ Seebeck coefficient and a reduction in the thermal conductivity in the direction of the hot-press axis, resulting in an overall 60% improvement in the thermoelectric figure of merit of Bi₂Se₃. Full article