Te Nanorods Research Articles

Electrochemical hydrogen evolution reaction boosted by constructing Ru nanoparticles assembled as a shell over semimetal Te nanorod surfaces in acid electrolyte.

Ru is a promising candidate for replacing Pt as a cost-effective and stable catalyst for hydrogen evolution when performing water electrolysis techniques. Its catalytic activity and efficiency for the hydrogen evolution reaction were found to be greatly boosted by carrying out a facile construction of Ru nanoparticles assembled as a shell over semimetal Te nanorod surfaces in an acid electrolyte. The high catalytic activity and efficiency of this product make its use promising in proton exchange membrane water electrolysis technology.

Shashlik-like Te–Bi2Te3hetero-nanostructures: one-pot synthesis, growth mechanism and their thermoelectric properties

Shashlik-like Te–Bi2Te3nanocomposites (consisting of Te nanorods and Bi2Te3nanoplates) were successfully synthesizedviaa solvothermal method.

Crystallographically textured SnSe nanomaterials produced from the liquid phase sintering of nanocrystals.

We report the thermoelectric performance of p-type nanocrystalline SnSe obtained from the liquid phase sintering of blends of SnSe nanocrystals and Te nanorods. A cycled hot press procedure at a temperature above the Te melting point promoted the formation of crystallographically textured SnSe nanomaterials with relative densities up to 93%. After consolidation, part of this Te was found within the SnSe lattice and part remained as elemental Te between the SnSe grains. The presence of Te during the SnSe consolidation resulted in SnSe nanomaterials with higher electrical conductivities and lower Seebeck coefficients and thermal conductivities. By adjusting the amount of Te, thermoelectric figures of merit (ZT) up to 1.4 at 790 K were measured in the direction of the uniaxial pressure, coinciding with the preferential a crystallographic axis. While this value matches the highest ZT value reported at this temperature for SnSe in the [100] crystal direction, the ZT values of the consolidated SnSe along the bc plane were relatively lower due to moderately low thermal conductivities in this plane.

Anchoring NiTe domains with unusual composition on Pb0.95Ni0.05Te nanorod as superior lithium-ion battery anodes and oxygen evolution catalysts

NiTe domains on the Pb0.95Ni0.05Te nanorod (defined as NiTe-PbNiTe, Ni = 0.3 g, atomic ratio INi:Pb = 1.5:1, 1.0 g, INi:Pb = 4.8:1) by Te self-scrifical template chemical conversion route has been designed. Thorough morphological characterizations revealed that significant variation of the morphology of products originated from varying the amount of Pb/Ni precursors injection. Thermodynamic calculation and experimental results indicated that Pb more active than Ni towards Te template at 298 K. Serving as lithium ion battery (LIB) anode material, the discharge capacities of the NiTe-PbNiTe (Ni = 0.3 g, atomic ratio INi:Pb = 1.5:1) electrode for the 1st and 200th cycles are 493.5 and 208.4 mA h g−1 at the current density of 0.5 A g−1, and NiTe-PbNiTe (Ni = 1.0 g, INi:Pb = 4.8:1) catalysts show electrocatalytic performance toward the oxygen evolution reaction (OER) with an overpotential of 387 mV at 10 mA cm−2 and a low Tafel slope of 96 mV dec−1 in 1 M KOH solution, which are superior to the pristine PbTe, NiTe and their powder mixtures (NiTe + PbTe) and other different Ni addition amount samples under the identify condition. This behaviour indicates that a suitable substitution of Pb with Ni and heterostructure nanorod do have profound synergistic effects on the electrochemical performance.

Facile fabrication of one-dimensional Te/Cu2Te nanorod composites with improved thermoelectric power factor and low thermal conductivity

In this study, Te/Cu2Te nanorod composites were synthesized using various properties of Cu2Te, and their thermoelectric properties were investigated. The nanorods were synthesized through a solution phase mixing process, using polyvinylpyrrolidone (PVP). With increasing Cu2Te content, the composites exhibited a reduced Seebeck coefficient and enhanced electrical conductivity. These characteristic changes were due to the high electrical conductivity and low Seebeck coefficient of Cu2Te. The composite containing 30 wt.% of Cu2Te nanorods showed the maximum power factor (524.6 μV/K at room temperature). The two types of nanorods were assembled into a 1D nanostructure, and with this structure, thermal conductivity decreased owing to the strong phonon scattering effect. This nanorod composite had a dramatically improved ZT value of 0.3, which was ~545 times larger than that of pristine Te nanorods.

Preparation and Characterization of Te/Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate)/Cu7Te4 Ternary Composite Films for Flexible Thermoelectric Power Generator.

In this work, Te/poly(3,4-ethylenedioxythiophene) (PEDOT):poly(styrenesulfonate) (PSS)/Cu7Te4 ternary thermoelectric (TE) nanocomposite films were successfully fabricated by physical mixing and then drop casting. An optimum power factor of 65.3 μW/mK2 was acquired from a composite film containing 95 wt % PEDOT:PSS-coated Te (PC/Te) nanorods at 300 K, which was about 5 times as large as that of the PC/Cu7Te4 nanorod film and about 3 times as large as that of the PC/Te nanorod film. The power factor reached 112.3 μW/mK2 when the temperature was 380 K. Scanning transmission electron microscopy (STEM) and high-resolution STEM were used to observe the detailed internal microstructure of the composite film, revealing that the Te nanorods were single crystalline and the Cu7Te4 rods polycrystalline. The composite film was in fact a three-dimensional network interconnected with the PC/Te and PC/Cu7Te4 nanorods. The enhancement of the TE properties was ascribed to the synergetic effect of the two kinds of nanorods and the double-carrier filtering effect at the two heterointerfaces of Te/PEDOT:PSS and Cu7Te4/PEDOT:PSS. An eight single-leg flexible TE device consisting of the optimized composite film was fabricated, which produced a voltage of 31.2 mV and a maximum output power of 94.7 nW at a temperature gradient of 39 K.

Preparation and thermoelectric properties of SWCNT/PEDOT:PSS coated tellurium nanorod composite films

In this work, single-walled carbon nanotube (SWCNT)/PEDOT:PSS coated Te nanorod (PC-Te) composite films were prepared by a simple vacuum assisted filtration method, and H2SO4 treatment was employed to improve the thermoelectric performance of the composite films. The addition of SWCNTs apparently improved the electrical conductivity while reduced the Seebeck coefficient of the composite films, resulting in a reduction of the power factor. After treated with H2SO4, the electrical conductivity of the composite films was further improved, and the Seebeck coefficient decreased slightly. As a consequence, an optimized power factor of 104 μW/mK2 (corresponding to the electrical conductivity of 332 S/cm and Seebeck coefficient of 56 μV/K, respectively) was obtained for the sample containing 70 wt% SWCNTs at 300 K. A flexible thermoelectric generator prototype was fabricated to demonstrate the output properties. The open circuit voltage and maximum output power delivered from the prototype were 5.6 mV and 53.6 nW, respectively, at a temperature difference of 44 K.

Preparation and thermoelectric properties of PEDOT:PSS coated Te nanorod/PEDOT:PSS composite films

Abstract PEDOT:PSS coated Te (PC Te) nanorod/PEDOT:PSS composite films were prepared by a drop-casting technique. H2SO4 treatment was employed to enhance thermoelectric (TE) properties of the composite films. The addition of PC Te nanorods increased both the electrical conductivity and the Seebeck coefficient of the composite films. An optimized power factor of 141.9 μW/mK2 was obtained for the film containing 90 wt% PC Te nanorods treated with 12 M H2SO4 at room temperature, which was 2.75 times as high as that of the untreated composite film, corresponding to the electrical conductivity and Seebeck coefficient of 204.6 S/cm and 83.27 μV/K, respectively. XPS and GIWAXS analysis revealed the removal of insulating PSS units and the rearrangement of PEDOT chains after the H2SO4 treatment. Finally, a 9-leg TE generator prototype was fabricated using the optimized composite film. The maximum output power and area output power density produced from the prototype were 47.7 nW and 57.2 μW/cm2, respectively, at the temperature difference of 40 K.

Blue Te Nanoneedles with Strong NIR Photothermal and Laser-Enhanced Anticancer Effects as "All-in-One" Nanoagents for Synergistic Thermo-Chemotherapy of Tumors.

The conventional blue Te nanostructures exhibit strong photoabsorption in the near-infrared (NIR) region but have ultralong lengths (tenths of micrometers), while purple Te nanostructures with short lengths (such as nanodots and nanorods) show extremely low intensity of the NIR band. These Te nanostructures cannot achieve simultaneously both the suitable size and high NIR absorption, undoubtedly hindering their bioapplication. Herein, blue Te nanoneedles are prepared through a facile one-pot reduction route for the first time, and they have strong NIR absorbance while maintaining the shortened length (<500 nm). Compared to purple Te nanorods, blue Te nanoneedles have higher photothermal conversion efficiency using a 915 nm laser and exhibit laser-enhanced antioxidative activity toward scavenging of free radicals. These blue nanoneedles show significant discrimination in cytotoxicity toward different cell-lines, and demonstrate anticancer activity induced by mitochondrial dysfunction. Furthermore, when blue Te nanoneedles are injected in tumors of mice, tumors can be detected by thermal/photoacoustic imaging, and satisfactory therapeutic effects are achieved through the synergistic thermo-chemotherapy in contrast to the limited therapeutic effect of Te-alone treatment. Therefore, these blue Te nanoneedles can be served as a novel theranostic nanoagent for simultaneous multimodal imaging and synergistic thermo-chemotherapy for tumors.

Cytotoxicity investigations of biogenic tellurium nanorods towards PC12 cell line.

The authors evaluated the cytotoxicity underlying mechanisms of biogenic tellurium (Te) nanorods (NRs) produced by the Pseudomonas pseudoalcaligenes strain Te on the PC12 cell line. The half-maximal inhibitory concentration (IC50) value was estimated at 5.05 ± 0.07 ng/ml for biogenic Te NRs and 2.44 ± 0.38 ng/ml for K2TeO3, respectively. The viability of PC12 was inhibited concentration dependent at doses of 1, 2.5, 5, 10, and 20 ng/ml. Te NRs principally induced late apoptosis or necrosis at IC50 concentration, without effect on caspase-3 activities. Furthermore, Te NRs reduced glutathione and enhanced malondialdehyde levels, and also reduced superoxide dismutase and catalase activities. These findings revealed that biogenic Te NRs were less toxic than K2TeO3. Additionally, they induced cytotoxity towards the PC12 cell line through the activation of late apoptosis independent of the caspase pathway, and may also enhance oxidative stress in the nervous system.

Hierarchical Bi2 Te3 Nanostrings: Green Synthesis and Their Thermoelectric Properties.

Bi2 Te3 hierarchical nanostrings have been synthesized through a solvothermal approach with the assistance of sucrose. The hierarchical Bi2 Te3 was supposed to be fabricated through a self-assembly process. Te nanorods first emerge with the reduction of TeO32- followed by heterogeneous nucleation of Bi2 Te3 nanoplates on the surface and tips of Te nanorods. Te nanorods further transform into Bi2 Te3 nanorods simultaneously with the nanoplates' growth leading to a hierarchical structure. By controlling the reaction kinetics by adding different amount of ethylene glycol, the length of nanorods and the number of nanoplates could be tailored. The use of sucrose is vital to the formation of hierarchical structure because it not only serves as a template for the well-defined growth of Te nanorods but also promotes the heterogeneous nucleation of Bi2 Te3 in the self-assembly process. The Bi2 Te3 nanomaterial shows a moderate thermoelectric performance because of its hierarchical structure. This study shows a promising way to synthesize Bi2 Te3 -based nanostructures through environmental friendly approach.

Morphology-tunable tellurium nanomaterials produced by the tellurite-reducing bacterium Lysinibacillus sp. ZYM-1.

Although tellurite is highly toxic to organisms, elemental tellurium nanomaterials (TeNMs) have many uses. The microbe-mediated reduction of tellurite to Te(0) has been shown to be a green and cost-effective approach for turning waste into wealth. However, it is difficult to tune the morphology of biogenic nanomaterials. In this study, a series of experiments was conducted to investigate the factors influencing tellurite reduction by the tellurite-reducing bacterium Lysinibacillus sp. ZYM-1, including pH, tellurite concentration, temperature, and heavy metal ions. The optimal removal efficiency of tellurite was respectively achieved at pH8, 0.5mM tellurite, and 40°C. All of the tested metal ions retarded the reduction of tellurite, especially Cd2+ and Co2+, which completely inhibited its reduction. Further characterization of the biogenic TeNMs indicated that their morphology could be tuned by the tellurite concentration, pH, temperature, and organic solvents used. Regular Te nanosheets were produced using 5mM tellurite. The TeNMs were primarily synthesized in the cell membrane. Hexagonal Te nanoplates, nanorods, nanoflowers, and nanobranches were synthesized when combining membrane fractions with tellurite and NADH. The diverse morphologies are assumed to be induced by the synergy between the reduction kinetics and the protein structure. Therefore, this study confirmed that the bacterium can tune the morphology of TeNMs, broadening the potential application of biogenic TeNMs.

Preparation and thermoelectric properties of two types of nanostructured tellurium with multi-walled carbon nanotubes

Two types of MWCNT/Te nanostructure composites with two different types of Te particles (powder and nanorods) and various MWCNT contents were synthesized and their thermoelectric properties were analyzed. Te powder was prepared by ball-milling Te beads and Te nanorods were synthesized by PVP-assisted solution-phase mixing. The highest power factor was achieved with 2 wt% of MWCNTs in both types of MWCNT/Te composites, attributed to the extremely high electrical conductivity of the MWCNTs. Above 2 wt%, the low Seebeck coefficient of the MWCNTs caused a decrease in the power factor. Additionally, the introduction of the MWCNTs into the Te matrix reduced the thermal conductivity of the composite by generating numerous boundaries. The maximum thermoelectric figure of merit (ZT) (0.0037 at room temperature) is achieved with 2 wt% of MWCNTs in the MWCNT/Te nanorod composites; this value is larger than the ZT values of pure Te and the MWCNT/Te powder composite.

Individual Adjustment of Electrical Conductivity and Thermopower Enabled by Multiple Interfaces in Polyaniline‐Based Ternary Hybrid Nanomaterials for High Thermoelectric Performances

AbstractRecent developed conducting polymer based hybrid thermoelectric (TE) materials provide a promising alternative route for energy conversion on a large scale. However, high thermopower largely relies on high content of low‐abundance elements, such as tellurium, which impedes the mass production of these materials. To optimize the compositions of the hybrids and further improve the TE properties, interfacial engineering is therefore employed to modulate the carrier transport properties in rationally designed multiwalled carbon nanotubes (MWCNTs)‐Te nanorod/polyaniline (PANI) ternary hybrid nanomaterials considering the similar π–π conjugated interactions among these constituents. The effects of MWCNTs and Te nanorods, especially the multiple interfaces formed between the constituents, on the TE performances and carrier transport behavior are studied in depth. Due to simultaneous increase in both electrical conductivity and thermopower, an optimal power factor of 54.4 µW m−1 K−2 is obtained in 52%Te‐16% MWCNT/PANI film, which is almost twice the value of binary Te/PANI film at the same Te content and comparable to that of 60% Te/PANI film. Moreover, the ternary hybrid film shows good mechanical stability. This study demonstrates an effective strategy to improve TE performances of conducting polymer based hybrids and has great potential for cost‐effective flexible energy conversion devices.

A p-type multi-wall carbon nanotube/Te nanorod composite with enhanced thermoelectric performance.

In this study, multi-walled carbon nanotube (MWCNT)/tellurium (Te) nanorod composites with various MWCNT contents are prepared and their thermoelectric properties are investigated. The composite samples are prepared by mixing Te nanorods with surface-treated MWCNTs. Te nanorods are synthesized by solution phase mixing using polyvinylpyrrolidone (PVP). The MWCNTs used in this study are surface-treated with a solution consisting of H2SO4 and HNO3. With increasing MWCNT content, the composite samples exhibit a reduction in the Seebeck coefficient and enhanced electrical conductivity. The maximum power factor of 5.53 μW m K−2 is observed at 2% MWCNT at room temperature. The thermal conductivity of the composite reduced after the introduction of MWCNTs into the Te nanorod matrix; this is attributed to the generation of heterostructured interfaces between MWCNTs and the Te nanorods. At room temperature, the composites containing 2% MWCNTs exhibited the maximum thermoelectric figure of merit (ZT), which is ∼3.91 times larger than that of pure Te nanorods.

Ultrafast synthesis of Te nanorods as cathode materials for lithium-tellurium batteries

Recently, tellurium has been regarded as a promising cathode material for rechargeable lithium-ion batteries due to its high theoretical volumetric capacity. However, a plethora of research are focusing on impregnating the tellurium into porous carbon materials by the thermal-diffusion method, which would consume large amounts of energy and take prolonged time. Herein, a carbon and binder-free cathode with 100% Te is fabricated by a facile galvanic replacement method on a nickle foam. Driven by the large electrochemical potential difference between Ni and Te, desirable amounts of Te can be obtained in just 10 min with no need of energy input. Li-Te batteries constructed by the as-obtained cathode show relatively good performance in DMSO solvent. To further elevate the performance of this battery especially at low current density, commercial carbon cloth is added between the separator and Te electrode as an interlayer. The cell with interlayer delivers a gravimetric capacity of 116.2 mAh g−1 after 70 cycles at the current density of 100 mA g−1, which is 2.8 times as high as that of a cell without interlayer (40.4 mAh g−1).

Facile Synthesis of CdTe Nanorods from the Growth of Te Nanorods

Facile Synthesis of CdTe Nanorods from the Growth of Te Nanorods

High‐Yield Synthesis of Multifunctional Tellurium Nanorods to Achieve Simultaneous Chemo‐Photothermal Combination Cancer Therapy

Tellurium (Te) is an important semiconductor material with low band‐gap energy, which has attracted considerable attention in recent years, due to its special chemical and physical properties and wide potential in electrochemistry, optoelectronics, and biological fields. This study demonstrates a facile and high‐yield synthesis strategy of Te nanorods (PTW‐TeNRs) decorated by polysaccharide–protein complex, which can achieve simultaneous chemo‐photothermal combination therapy against cancers. PTW‐TeNRs alone possess high stability under physiological conditions, potent anticancer activities through induction of reactive oxygen species overproduction, and high selectivity among tumor and normal cells. More importantly, they exhibit strong near‐infrared (NIR) absorbance and good photothermal conversion ability from NIR light to heat energy. Furthermore, in combination with NIR laser irradiation, PTW‐TeNRs exhibit excellent chemo‐photothermal efficiency and low toxicity as evidenced by highly efficient tumor ablation ability, but show no obvious histological damage to the major organs. Taken together, this study provides a valid tactic for facile synthesis of multifunctional tellurium nanorods for efficient and combinational cancer therapy.

Enhanced thermoelectric power factor and low thermal conductivity in one-dimensional Te/Ag2Te composites

Abstract We reports the synthesis and characterization of Te/Ag 2 Te nanorod composites with various Ag 2 Te contents. The composite samples were prepared by mixing Te and Ag 2 Te nanorods synthesized by polyvinylpyrrolidone (PVP)-assisted solution-phase mixing. The thermoelectric properties of the prepared composites vary according to the Ag 2 Te content. Furthermore, the samples exhibit an enhancement in electrical conductivity and a reduction in the Seebeck coefficient with increasing Ag 2 Te content. The maximum power factor (350.71 µV/K at room temperature) is observed for the sample containing 30% Ag 2 Te. The samples were assembled as 1D nanostructures, which led to a decrease in thermal conductivity owing to the strong phonon scattering effect. The maximum thermoelectric figure of merit (ZT) at room temperature, 0.34 was obtained for the sample with 30% Ag 2 Te content. This value is 480% larger than that obtained for the pristine Te nanorod samples.

Preparation and properties of PEDOT:PSS/Te nanorod composite films for flexible thermoelectric power generator

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) functionalized Te (PF-Te) nanorods were in situ synthesized. A simple and efficient vacuum-assisted filtration method was employed to integrate the PF-Te nanorods with PEDOT:PSS to form PEDOT:PSS/PF-Te composite films. By varying the content of PF-Te nanorods, the Seebeck coefficient of the composites increases from 15.6 to 51.6 μV/K, while the electrical conductivity decreases from 1262 to 122.4 S/cm. A maximum power factor of 51.4 μW/mK2 is obtained from a sample containing 70 wt% PF-Te nanorods at room temperature. An 8 single-leg flexible thermoelectric generator prototype was fabricated using the as-prepared PEDOT:PSS/PF-Te composite film containing 70 wt% PF-Te on a polyimide substrate with Ag electrodes. The prototype produced an output voltage of 2.5 mV at a 13.4 K temperature difference between human body and the environment.