13494-80-9 Usage
Uses
Used in Metallurgy:
Tellurium is used as an additive to improve the machinability, strength, and hardness of stainless steel, copper, and lead-based alloys, steel, and cast iron. It enhances the properties of these metals and protects lead from the corrosive action of sulfuric acid.
Used in Rubber Manufacturing:
Tellurium is used as a curing agent for natural and synthetic rubber, improving the mechanical properties of the rubber and imparting resistance to heat and abrasion.
Used in Electronics Industry:
Tellurium is used in small amounts for lasers and photoreceptors in the electronics industry. It is also used in semiconductor research, with tellurides of lead and bismuth used in thermoelectric devices for power generation and refrigeration.
Used in Glass, Ceramics, and Enamels:
Tellurium is used as a coloring agent in glass, ceramics, and enamels, providing a unique color to these materials.
Used in Catalysts:
Traces of tellurium incorporated into platinum catalysts make the catalytic hydrogenation of nitric oxide favorable to forming hydroxylamine.
Used in Special Alloys:
Tellurium is used in the manufacture of special alloys with marked electrical resistance.
Used in Storage Batteries and Depilatories:
Tellurium is used in vulcanizing rubber, in storage batteries, and as a depilatory, which removes hair from skin.
Used in Semiconductors:
Many tellurium salts find application in semiconductors, and it is used as a p-type semiconductor, although more efficient elements can perform better in this role.
Used in Chinaware, Porcelains, and Enamels:
Tellurium is used as a coloring agent in chinaware, porcelains, and enamels, as well as in producing a black finish on silverware.
Used in Thermoelectrical Devices:
Tellurium is used in thermoelectric devices, along with lithium, to make special batteries for spacecraft and infrared lamps.
Used in Vulcanizing Rubber and Ceramics:
Tellurium is used in vulcanizing rubber, in storage batteries, and as a coloring agent in ceramics.
Used in Semiconductor Research:
Tellurium is widely used in semiconductor research, with many of its salts finding applications in this field.
History
The element was discovered by Muller von Reichenstein in 1782 while investigating a bluish-white ore of gold. The element was isolated from this ore by Klaproth in 1798, who suggested the name “tellurium” after the Latin word tellus, meaning earth. Tellurium occurs in nature only in minute quantities. It is found in small amounts in many sulfide deposits. One of the more common tellurium minerals is calaverite, AuTe2 , in which the metal is combined with gold. Some other tellurium minerals are altaite, PbTe; sylvanite, (Ag,Au)Te2; rickardite, Cu4Te3; tetradymite, Bi2Te2S; petzite, Ag3AuTe2 and coloradoite, HgTe. The metal is found in the native state and also in the form of its dioxide, tellurite, TeO2. The abundance of tellurium in the earth’s crust is estimated to be about 1 μg/kg.
History
Discovered by Muller von Reichenstein in 1782; named
by Klaproth, who isolated it in 1798. Tellurium is occasionally
found native, but is more often found as the telluride of
gold (calaverite), and combined with other metals. It is recovered
commercially from the anode muds produced during
the electrolytic refining of blister copper. The U.S., Canada,
Peru, and Japan are the largest producers of the element.
Crystalline tellurium has a silvery-white appearance, and
when pure exhibits a metallic luster. It is brittle and easily pulverized.
Amorphous tellurium is formed by precipitating tellurium
from a solution of telluric or tellurous acid. Whether
this form is truly amorphous, or made of minute crystals, is
open to question. Tellurium is a p-type semiconductor, and
shows greater conductivity in certain directions, depending
on alignment of the atoms. Its conductivity increases slightly
with exposure to light. It can be doped with silver, copper,
gold, tin, or other elements. In air, tellurium burns with a
greenish-blue flame, forming the dioxide. Molten tellurium
corrodes iron, copper, and stainless steel. Tellurium and its
compounds are probably toxic and should be handled with
care. Workmen exposed to as little as 0.01 mg/m3 of air, or
less, develop “tellurium breath,” which has a garlic-like odor.
Forty-two isotopes and isomers of tellurium are known, with
atomic masses ranging from 106 to 138. Natural tellurium
consists of eight isotopes, two of which are radioactive with
very long half-lives. Tellurium improves the machinability of
copper and stainless steel, and its addition to lead decreases
the corrosive action of sulfuric acid on lead and improves its
strength and hardness. Tellurium catalysts are used in the oxidation
of organic compounds and are used in hydrogenation
and halogenation reactions. Tellurium is also used in electronic
and semiconductor devices. It is also used as a basic
ingredient in blasting caps, and is added to cast iron for chill
control. Tellurium is used in ceramics. Bismuth telluride has
been used in thermoelectric devices. Tellurium costs about
50￠/g, with a purity of about 99.5%. The metal with a purity
of 99.9999% costs about $5/g.
Production Methods
Tellurium is recovered from the anode slimes produced in electrolytic refining of copper. Other metals present in these slimes are gold, silver, and selenium, which are all recovered as by-products in the extraction of tellurium. Tellurium is leached with caustic soda solution and the leachate upon neutralization precipitates tellurium dioxide, TeO2, in crude and impure form. A part of tellurium remaining in the slimes can be recovered during extraction of gold and silver. In this gold and silver recovery process, tellurium incorporates into the soda slag obtained from roasting the slimes in a furnace. Soda slag is produced when leached with a solution of caustic soda. The liquor is neutralized to form a crude precipitate of tellurium dioxide.
Crude tellurium dioxide is dissolved in a strong solution of caustic soda to form sodium tellurite. Electrolysis of sodium tellurite solution deposits tellurium metal on the stainless steel cathode.
Also, the tellurium metal can be prepared by thermal reduction of dioxide. However, prior to reduction crude dioxide is refined by successive caustic leaching and neutralization steps mentioned above.
Refined tellurium contains traces of lead, copper, iron, selenium, and other impurities. Highly pure tellurium can be obtained either by distilling refined tellurium in vacuum or by the zone melting process. The last traces of selenium can be removed as hydride by treating molten tellurium with hydrogen.
Production Methods
Elemental tellurium (Te) has some metallic properties,
although it is classed as a nonmetal or metalloid. The
name is derived from the Latin word for earth, tellus.
Tellurium is occasionally found naturally, more often as
telluride of gold, calaverite. The elemental form has a bright
luster, is brittle, readily powders, and burns slowly in air.
Tellurium exists in two allotropic forms, in the form of
powder and hexagonal crystalline (isomorphous) with gray
selenium. The concentration in the earth’s crust is about
0.002 ppm. It is recovered from anode muds during the
refining of blister copper. It is also found in various sulfide
ores along with selenium and is produced as a by-product of
metal refineries. The United States, Canada, Peru, and Japan
are the largest producers.
Tellurium’s industrial applications include its use as a
metallurgical additive to improve the characteristics of alloys
of copper, steel, lead, and bronze. Increased ductility results
from its use in steel and copper alloys. Addition of tellurium
to cast iron is used for chill control, and it is a basic part of
blasting caps. It is used in some chemical processes as a
catalyst for synthetic fiber production, and as a vulcanizing
agent and accelerator in the processing of rubber.
Isotopes
There are a total of 48 isotopes of tellurium. Eight of these are consideredstable. Three of the stable ones are actually radioactive but have such long half-livesthat they still contribute to the natural abundance of tellurium in the crust of the Earth.The isotope Te-123 (half-life of 6×10+14 years) contributes 0.89% of the total telluriumfound on Earth, Te-128 (half-life of 7.7×10+24 years) contributes 31.74% to the naturalabundance, and Te-130 (half-life of 0.79×10+21 years) contributes 34.08% to the telluriumin the Earth’s crust. The other five stable isotopes and the percentage of theirnatural abundance are as follows: Te-120 = 0.09%, Te-122 = 2.55%, Te-124 = 4.74%,Te-125 = 7.07%, and Te-126 = 18.84%. The other 40 isotopes are all radioactive withshort half-lives.
Origin of Name
The name “tellurium” is derived from the Latin word for Earth, tellus.
Characteristics
The pure form of tellurium burns with a blue flame and forms tellurium dioxide (TeO2).It is brittle and is a poor conductor of electricity. It reacts with the halogens of group 17, butnot with many metals. When it reacts with gold, it forms gold telluride. Tellurium is insolublein water but readily reacts with nitric acid to produce tellurous acid. If inhaled, it produces agarlic-like odor on one’s breath.
Reactivity Profile
Tellurium is attacked by chlorine fluoride with incandescence. When Tellurium and potassium are warmed in an atmosphere of hydrogen, combination occurs with incandescence [Mellor 11:40. 1946-47]. Burning Tellurium produces toxic Tellurium oxide gas. Avoid solid sodium, halogens, interhalogens, metals, hexalithium disilicide. Reacts with nitric acid; reacts with concentrated sulfuric acid forming a red solution. Dissolves in potassium hydroxide in the presence of air with formation of deep red solution; combines with halogens. Avoid antimony and chlorine trifluoride; chlorine trifluoride reacts vigorously with Tellurium producing flame. Fluorine and Tellurium react with incandescence. Lithium silicide attacks Tellurium with incandescence. Reaction with zinc is accompanied by incandescence (same potential with cadmium, only hazard is less). A vigorous reaction results when liquid Tellurium is poured over solid sodium [EPA, 1998].
Hazard
All forms of tellurium are toxic in gas form. The vapors of all the compounds of the dustand powder forms of the element should not be inhaled or ingested. When a person is poisonedwith tellurium, even in small amounts, the breath will smell like garlic.
Health Hazard
Although tellurium in elemental form haslow toxicity, ingestion can produce nausea,vomiting, tremors, convulsions, and centralnervous system depression. In addition,exposure to the metal or to its compoundscan generate garlic-like odor in breath, sweat,and urine. Such odor is imparted by dimethyltelluride that is formed in the body. Oralintake of large doses of the metal or itscompounds can be lethal. Clinical symptomsare similar for most tellurium salts,which include headache, drowsiness, lossof appetite, nausea, tremors, and convulsions.High exposure can produce metallictaste, dry throat, chill and other symptoms.Inhalation of dust or fume of the metalcan cause irritation of the respiratory tract.Chronic exposure can produce bronchitis andpneumonia.
Fire Hazard
A finely divided suspension of elemental Tellurium in air will explode. Insoluble in water. Burning Tellurium produces toxic Tellurium oxide gas. Avoid solid sodium, halogens, interhalogens, metals, hexalithium disilicide. Reacts with nitric acid; reacts with concentrated sulfuric acid forming a red solution. Dissolves in potassium hydroxide in the presence of air with formation of deep red solution; combines with halogens. Avoid antimony and chlorine trifluoride; chlorine trifluoride reacts vigorously with Tellurium producing flame. Fluorine and Tellurium react with incandescence. Lithium silicide attacks Tellurium with incandescence. Reaction with zinc is accompanied by incandescence (same potential with cadmium, only hazard is less). A vigorous reaction results when liquid Tellurium is poured over solid sodium.
Flammability and Explosibility
Nonflammable
Safety Profile
Poison by ingestion and intratracheal routes. An experimental teratogen. Exposure causes nausea, vomiting, tremors, convulsions, respiratory arrest, central nervous system depression, and garlic odor to breath. Aerosols of tellurium, tellurium dioxide, and hydrogen telluride cause irritation of the respiratory system and may lead to the development of bronchitis and pneumonia. Experimental reproductive effects. Under the proper conditions it undergoes hazardous reactions with halogens (e.g., chlorine, fluorine), interhalogens (e.g., bromine pentafluoride, chlorine fluoride, chlorine trifluoride), metals (e.g., cadmium, potassium, sodium, platinum, tin, zinc), hexalithium disilicide, silver bromate, silver iodate. When heated to decomposition it emits toxic fumes of Te. See also TELLURIUM COMPOUNDS.
Potential Exposure
The primary use of tellurium is in the vulcanization of rubber and as an additive in ferritic steel production. It is also used as a carbide stabilizer in cast iron, a chemical catalyst; a coloring agent in glazes and glass; a thermocoupling material in refrigerating equipment; as an additive to selenium rectifiers; in alloys of lead, copper, steel, and tin for increased resistance to corrosion and stress, workability, machinability, and creep strength; and in certain culture media in bacteriology. Since tellurium is present in silver, copper, lead, and bismuth ores, exposure may occur during purification of these ores.
Environmental Fate
Metals are recalcitrant to degradation; therefore, no biodegradation studies have been performed on tellurium. No aquatic bioaccumulation data exist for tellurium; however, based on its density and low water solubility, it is unlikely to present a concern for bioaccumulation in the water column. No environmental monitoring data are available on the levels of tellurium in sediment or sediment-dwelling organisms. Therefore, it is unclear whether tellurium has the potential to bioaccumulate in this compartment. In humans, tellurium accumulates in the bones. Based on this, it may be assumed that tellurium has the potential to bioaccumulate in vertebrates.
Purification Methods
Purify it by zone refining and repeated sublimation to an impurity of less than 1 part in 108 (except for surface contamination by TeO2). [Machol & Westrum J Am Chem Soc 80 2950 1958.] Tellurium is volatile at 500o/0.2mm. It has also been purified by electrode deposition [Mathers & Turner Trans Amer Electrochem Soc 54 293 1928].
Toxicity evaluation
Tellurium has a low toxicity in its elemental form, but dimethyltelluride
is formed in the body. Tellurium caused a highly
synchronous primary demyelination of peripheral nerves,
related to the inhibition of squalene epoxidase, which blocks
cholesterol synthesis. The sequence of metabolic events in
sciatic nerve following tellurium treatment initially involves
inhibition of the conversion of squalene to 2,3-epoxysqualene,
and this block in the cholesterol biosynthesis pathway results,
either directly or indirectly, in the inhibition of the synthesis of
myelin components and the breakdown of myelin. The efficacy
of garlic as a lipid-lowering agent has been recognized, but the
biochemical mechanisms underlying this action are currently
unknown. It is possible that organic tellurium compounds,
which are found in high concentration in fresh garlic buds, may
contribute to this action by inhibiting squalene epoxidase, the
penultimate enzyme in the synthetic pathway of cholesterol.
Weanling rats fed a diet rich in tellurium develop a demyelinating
polyneuropathy because of inhibition of this enzyme in
peripheral nerves. Chronic exposure to small amounts of
tellurium found in garlic might reduce endogenous cholesterol production through inhibition of hepatic squalene epoxidase
and so reduce cholesterol levels. Tellurium may also contribute
to the characteristic odor of garlic.
Incompatibilities
Finely divided powder or dust may be flammable and explosive. Violent reaction with halogens, interhalogens, zinc and lithium silicide; with incandescence. Incompatible with oxidizers, cadmium; strong bases; chemically active metals; silver bromate; nitric acid.
Check Digit Verification of cas no
The CAS Registry Mumber 13494-80-9 includes 8 digits separated into 3 groups by hyphens. The first part of the number,starting from the left, has 5 digits, 1,3,4,9 and 4 respectively; the second part has 2 digits, 8 and 0 respectively.
Calculate Digit Verification of CAS Registry Number 13494-80:
(7*1)+(6*3)+(5*4)+(4*9)+(3*4)+(2*8)+(1*0)=109
109 % 10 = 9
So 13494-80-9 is a valid CAS Registry Number.
InChI:InChI=1/Te
13494-80-9Relevant articles and documents
Efficient quenching of TGA-capped CdTe quantum dot emission by a surface-coordinated europium(III) cyclen complex
Gallagher, Shane A.,Comby, Steve,Wojdyla, Michal,Gunnlaugsson, Thorfinnur,Kelly, John M.,Gun'Ko, Yurii K.,Clark, Ian P.,Greetham, Gregory M.,Towrie, Michael,Quinn, Susan J.
, p. 4133 - 4135 (2013)
Extremely efficient quenching of the excited state of aqueous CdTe quantum dots (QDs) by photoinduced electron transfer to a europium cyclen complex is facilitated by surface coordination to the thioglycolic acid capping ligand. The quenching dynamics are elucidated using steady-state emission and picosecond transient absorption.
X-ray luminescence of CdTe quantum dots in LaF3:Ce/CdTe nanocomposites
Hossu, Marius,Liu, Zhongxin,Yao, Mingzhen,Ma, Lun,Chen, Wei
, (2012)
CdTe quantum dots have intense photoluminescence but exhibit almost no x-ray luminescence. However, intense x-ray luminescence from CdTe quantum dots is observed in LaF3:Ce/CdTe nanocomposites. This enhancement in the x-ray luminescence of CdTe quantum dots is attributed to the energy transfer from LaF3:Ce to CdTe quantum dots in the nanocomposites. The combination of LaF3:Ce nanoparticles and CdTe quantum dots makes LaF3:Ce/CdTe nanocomposites promising scintillators for radiation detection.
Electron energy loss spectroscopy (EELS) of H2O, H2S, H2Se and H2Te
Pradeep, T.,Hegde, M. S.
, p. 883 - 888 (1988)
Electronic excitation in H2O, H2S, H2Se and H2Te molecules has been studied by the EELS technique.Spectra of H2S and H2Se are remarkably similar with the 1b1-nd transition most intense.The intensity of the first transition 1b1-nsa1 decreases through H2O to H2Se and this transition is absent in H2Te.Transitions observed by EELS have been compared with optical absorption studies.A correlation diagram of the occupied and the excited states has been provided for these four molecules by making use of UVPES and EELS.
Upconversion luminescence of CdTe nanoparticles
Joly, Alan G.,Chen, Wei,McCready, David E.,Malm, Jan-Olle,Bovin, Jan-Olov
, (2005)
Efficient upconversion luminescence is observed from CdTe nanoparticles in solution and precipitated as solids. In the solids, the upconversion luminescence spectrum is significantly red shifted relative to the photoluminescence spectrum, whereas in solution, there is very little spectral shift. The upconversion luminescence exhibits a near-quadratic laser power dependence, both at room temperature and at 10 K. Both the upconversion and photoluminescence show similar decay dynamics with the solid samples showing shorter lifetimes compared to the solutions. This lifetime shortening is attributed to surface-state quenching. These results indicate that two-photon excitation is the likely upconversion excitation mechanism in these particles and that phonon-populated trap states do not contribute to the upconversion.
Synthesis and structures of new ternary aluminum chalcogenides: LiAlSe2, α-LiAlTe2, and β-LiAlTe2
Kim, Joonyeong,Hughbanks, Timothy
, p. 3092 - 3097 (2000)
The synthesis and crystal structures of new ternary aluminum chalcogenides, LiAlSe2, α-LiAlTe2, and β-LiAlTe2, are reported. These compounds are synthesized by solid-state reaction at 800 °C. The single-crystal X-ray structures of these compounds have been determined. LiAlSe2: a = 6.8228(9) A, b = 8.266(1) A, c = 6.5236(7) A, Pna21 (No. 33, Z = 4). α-LiAlTe2: a = 6.5317(4) A, c = 11.6904(9) A, I42d (No. 122, Z = 4). β-LiAlTe2: a = 4.4810(6) A, c = 7.096(1) A, P3m1 (No. 156, Z = 1). These ternary compounds are formed by fusion of AlQ4 (Q = Se, Te) tetrahedra. LiAlSe2 shows β-NaFeO2 structure type, which can be viewed as a wurtzite superstructure. α-LiAlTe2 adopts chalcopyrite structure type. In LiAlSe2 and α-LiAlTe2, AlQ4 (Q = Se, Te) tetrahedra share four corners to build three-dimensional structures and Li atoms are located in the tetrahedral sites between the chalcogen layers. β-LiAlTe2 has polar layers formed by three-corner shared AlTe4 tetrahedra, and Li cations are in the distorted antiprisms between the layers. 7Li MAS NMR studies show that chemical shifts of Li in these ternary chalcogenides are nearly identical regardless of different chemical environments.
The photophysical studies of a mixture of CdTe quantum dots and negatively charged zinc phthalocyanines
Moeno, Sharon,Nyokong, Tebello
, p. 1953 - 1958 (2008)
Fluorescence resonance energy transfer (FRET) studies were carried out with quantum dots capped with thioglycolic acid (TGA) and 2-mercaptoethanol (2-ME) and negatively charged phthalocyanines {Zn tetracarboxy (ZnTCPc), Zn octacarboxy (ZnOCPc) and Zn tetrasulfo (ZnTSPc) phthalocyinines} in a 0.1 NaOH:EtOH (50:50) solvent mixture. The best overlap between emission spectra of the donor (QDs) and the absorption spectra of the acceptor (ZnPc derivatives) was observed for TGA capped QDs, very little overlap was obtained for 2-ME QDs. ZnTSPc gave the highest FRET efficiency (0.3), with ZnOCPc and ZnTCPc giving a FRET efficiency of 0.2. The ΦT values of the MPcs generally decreased in the presence of the QD whereas the triplet lifetimes (τT) of the ZnPc derivatives were higher in the presence of QDs.
Spectroscopic behavior of cationic metallophthalocyanines in the presence of anionic quantum dots
Idowu, Mopelola,Nyokong, Tebello
, p. 411 - 416 (2010)
The interactions and spectroscopic properties between cationic zinc phthalocyanine derivatives (peripherally and non-peripherally tetrasubstituted and peripherally octa substituted with 2-diethylmethylaminoethylsulfanyl (βTZnPc, αTZnPc and βOZnPc)) and CdTe core quantum dots (QDs) capped with mercaptopropionic acid or thioglycolic acid (represented as CdTe@MPA and CdTe@TGA, respectively) have been studied in methanol:water mixture. Strong coupling of MPcs was deduced from the interaction since the UV-vis spectroscopic studies of the ground state complex formed on mixing both components showed loss of the phthalocyanine monomeric band with the formation of a dimeric band (spectrum of aggregated species). The dimerization constants were of the order of 104 M-1.
Synthesis of highly stable CdTe/CdS quantum dots with biocompatibility
Liu, Ying-Fan,Xie, Bing,Yin, Zhi-Gang,Fang, Shao-Ming,Zhao, Jian-Bo
, p. 1501 - 1506 (2010)
Thioglycolic acid (TGA) is a popular coating material for the preparation of aqueous quantum dots (QDs), yet dihydrolipoic acid (DHLA) has not been studied much. Here we present a detailed study on the aqueous synthesis of CdTe/CdS quantum dots with a DHLA coating. The outer CdS shell and DHLA stabilizer provide efficient confinement of electron and hole wave functions inside the nanocrystal as well as high photochemical stability. At the optimum ratios and reaction conditions, the results indicate that the DHLA-capped CdTe/CdS QDs exhibit high fluorescence quantum yields (QYs) of about 48% over a spectral range of 551-571 nm, and the best QY is 87%. These DHLA-capped core-shell QDs are highly biocompatible and monodisperse. In particular, they have exhibited excellent colloidal and photostability over one year of study. The synthesis of QDs by using DHLA as stabilizer is simple and environmentally friendly, and it can easily be extended to the large-scale, aqueous-phase production of QDs. At a QD dose of 120μg/mL, TGA-stabilized CdTe QDs induce 9.5% hemolysis, whereas DHLA-stabilized CdTe/CdS QDs induce only 3% hemolysis. Hemolytic results indicate that DHLA-slabilized QDs are more biocompatible than TGA-cappod CdTo QDs, which is especially important, for QDs as biomarkers in biological detection and diagnosis.
Matrix isolation study of D2Te and H2Te molecules in solid argon
Montano, P. A.,Nagarathna, H. M.,Newlin, D.,Stewart, G. W.
, p. 5558 - 5560 (1981)
A careful synthesis of H2Te and D2Te and their isolation in solid argon are reported.Rare gas metrix isolated molecules of H2Te and D2Te were studied using Moessbauer spectroscopy.The gaseous species were identified using mass spectrometry.Moessbauer parameters were analyzed using extended Hueckel calculations.A good agreement between the experimental and the calculated value of the quadrupole splitting requires a smaller quadrupole moment for the excited state of 125Te then that reported in the literature.A 10percent increase in the QS for D2Te is explained as due to the enhancement of 3> caused by a slight contraction of the D-Te bond.
NiTe2 Nanowire Outperforms Pt/C in High-Rate Hydrogen Evolution at Extreme pH Conditions
Anantharaj, Sengeni,Karthick, Kannimuthu,Kundu, Subrata
, p. 3082 - 3096 (2018)
Better hydrogen generation with nonprecious electrocatalysts over Pt is highly anticipated in water splitting. Such an outperforming nonprecious electrocatalyst, nickel telluride (NiTe2), has been fabricated on Ni foam for electrocatalytic hydrogen evolution in extreme pH conditions, viz., 0 and 14. The morphological outcome of the fabricated NiTe2 was directed by the choice of the Te precursor. Nanoflakes (NFs) were obtained when NaHTe was used, and nanowires (NWs) were obtained when Te metal powder with hydrazine hydrate was used. Both NiTe2 NWs and NiTe2 NFs were comparatively screened for hydrogen evolution reaction (HER) in extreme pH conditions, viz., 0 and 14. NiTe2 NWs delivered current densities of 10, 100, and 500 mA cm-2 at the overpotentials of 125 ± 10, 195 ± 4, and 275 ± 7 mV in 0.5 M H2SO4. Similarly, in 1 M KOH, overpotentials of 113 ± 5, 247 ± 5, and 436 ± 8 mV were required for the same current densities, respectively. On the other hand, NiTe2 NFs showed relatively poorer HER activity than NiTe2 NWs, which required overpotentials of 193 ± 7, 289 ± 5, and 494 ± 8 mV in 0.5 M H2SO4 for the current densities of 10 and 100 mA cm-2 and 157 ± 5 and 335 ± 6 mV in 1 M KOH for the current densities of 10 and 100 mA cm-2, respectively. Notably, NiTe2 NWs outperformed the state-of-the-art Pt/C 20 wt % loaded Ni foam electrode of comparable mass loading. The Pt/C 20 wt % loaded Ni foam electrode reached 500 mA cm-2 at 332 ± 5 mV, whereas NiTe2 NWs drove the same current density with 57 mV less. These encouraging findings emphasize that a NiTe2 NW could be an alternative to noble and expensive Pt as a nonprecious and high-performance HER electrode for proton-exchange membrane and alkaline water electrolyzers.
