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Herein, we report nanostructures of NiTe and NiTe2 nanorods (NRs) with stoichiometric chemical compositions grown in an efficient one-pot hydrothermal approach. In the synthesis, hydrazine hydrate played multiple roles, such as a dissolving agent, reductant, and structure-directing agent. The samples were characterized using various analytical methods, such as X-ray diffraction, high-resolution transmission electron microscopy (HR-TEM), nitrogen adsorption/desorption measurements, energy-dispersive X-ray spectrometer (EDX), field-emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), and UV–Vis diffuse reflectance spectroscopy consequently. Adjustment of the Ni:Te (1:1, 1:2) precursors molar ratio reflected the results as desirable stoichiometric crystal structures of NiTe (hexagonal, P 6 3 / mmc ) and NiTe2 (trigonal, P 3 ¯ m 1 ); further, the FE-SEM images displayed the evolution of nanorod morphology with an intermediate of tellurium template by the influence of the Kirkendall effect. The TEM pictures are likely to show the formation of two distinguished nanorods with different particle sizes. Both NiTe NRs and NiTe2 NRs were developed along the hexagonal direction; however, NiTe NRs include relatively small particles, and NiTe2 NRs considerably larger ones. The high-resolution XPS spectra revealed the surface structure and chemical composition of the Ni–Te system under Ni 2p and Te 3d spectra with the characteristic peaks of Ni2+, Ni0, Te2−, and Te4+ assigned based on the influence of hydrazine reduction and surface oxidation, respectively. Therefore, the optical band gap value of the prepared NiTe and NiTe2 NRs phases was found to be 3.25 and 3.0 eV, showing the semiconductor properties and potential for a wide range of applications. [ABSTRACT FROM AUTHOR]

Summary: The rational strategy to design the well‐ordered morphology of the metal oxides with defective engineering and tailoring them into specific electrode fabrication can significantly improve their electrochemical properties for high‐performance energy storage systems. Herein, we adopted an effective strategy to introduce oxygen‐defect into the well‐ordered three‐dimensional flower‐like CoMoO4 nanoarchitecture. The Co‐Mo precursor leads to the introduction of oxygen‐defects into the CoMoO4 (rCMO) nanoarchitecture during the heat‐treatment under an oxygen‐controlled environment (argon). The oxygen‐defects in the material could facilitate abundant electroactive sites and intrinsically enhance the conductivity and supercapacitor performance. The oxygen‐defect CoMoO4 (rCMO) exhibits a specific capacity of 531 mAh g−1 at a current density of 1 A g−1 compared to the pristine CoMoO4 (CMO; ambient atmosphere) of 322 mAh g−1 under the same current density. Meanwhile, the fabricated hybrid supercapacitor (HSC) of rCMO//AC provides a maximum specific capacitance of 159 F g−1. Further, it distributes an energy density of 49.87 Wh kg−1 at the power density of 845.45 W kg−1 with an excellent cyclic life of ~91.03% over 10 000 cycles. [ABSTRACT FROM AUTHOR]