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Mg Doped Perovskite LaNiO <sub/>3</sub> Nanofibers as an Efficient Bifunctional Catalyst for Rechargeable Zinc–Air Batteries
摘要： Rational design of efficient and durable bifunctional catalysts toward oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is important for rechargeable zinc-air batteries. Herein, Mg doped perovskite LaNiO3 (LNO) nanofibers (LNMO NFs) were prepared by a facile electrospinning method combined with subsequent calcination. LNMO NFs show a more positive half-wave potential of 0.69V and a lower overpotential of 0.45 V at a current density of 10 mA cm-2 than those of the pristine LNO NFs. As an air electrode for zinc-air battery, the cell with LaNi0.85Mg0.15O3 NFs catalyst is able to deliver a high specific capacity of 809.9 mAh g-1 at a current density of 5 mA cm-2. It also shows an excellent cycling stability over 110 h at a current density of 10 mA cm?2. DFT calculation results demonstrate that the LNMO surface binds oxygen stronger than LNO, which contributes to enhanced OER activity as observed in our experiments. The results indicate that LNMO NFs is an efficient and durable bifunctional catalyst for zinc-air batteries.
关键词： bi-functional catalyst,Mg doped LaNiO3 nanofibers,electrospinning,density functional theory calculation,zinc-air batteries
更新于2025-11-14 17:04:02
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Ultrathin nanowire based on icosahedral W@Au12 and application as NO gas sensor
摘要： In this study, we used first-principles calculations to investigate the structural and electronic properties of an ultrathin nanowire formed by assembling icosahedral W@Au12 clusters and its application as a NO gas sensor. An ultrathin nanowire with a diameter of about 5.52 ? was produced via the coalescence of icosahedral W@Au12 clusters. The W@Au12-based nanowire exhibited semiconducting properties with a direct band gap. Frequency analysis and molecular dynamics simulations indicated that the nanowire was particularly stable at T = 300 K. The nanowire chemisorbed a NO molecule with moderate adsorption energy, and the N atom in NO bonding with the Au atom was the most stable bond. Analysis of the Boltzmann distribution and transition state demonstrated that the most stable configuration was particularly likely to form. The electronic properties of the W@Au12-based nanowire were changed dramatically by NO adsorption, with a transition from semiconducting to conducting behavior after NO adsorption. However, the adsorption of CO2, CH4, O2, H2, N2, or H2O molecules had little effect on the conductance of the nanowire. Our results indicated that the W@Au12-based nanowire sensor was highly sensitive and selective. The recovery time for the nanowire-based NO sensor was about 12 s at T = 300 K. Therefore, due to its moderate adsorption energy, significant change in the electric conductivity, and very rapid recovery time, we conclude that the W@Au12-based nanowire is a promising gas sensor with high performance at NO detection.
关键词： Icosahedral W@Au12,Assembly,Density functional theory calculation,NO gas sensor,Nanowire
更新于2025-09-19 17:15:36
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Structural, vibrational and optical properties of an organic-inorganic hybrid crystal of benzyl 4-aminopyridinium tetrabromocadmate(II) based on DFT calculations
摘要： An organic-inorganic hybrid crystal, [Bz-4-NH2Py]2[CdBr4](1) (Bz-4-NH2Py = 1-benzyl-4'-aminopyridinium), was grown successfully by slow evaporation solution growth method at room temperature and characterized. In tetrachlorocadmate(II) dianion, the CdII ion is coordinated by four Br atoms in a close to tetrahedral geometry. The crystal packing is stabilized by C-H···Br hydrogen bonds between [Bz-4-NH2Py]+ cations and [CdBr4]2- anion forming a three-dimensional network. Powder XRD diffraction study confirms the crystalline nature of the title compound. Thermal stability and the gaseous products of decomposition at 362 oC were examined by TG-DTA-MS technique. The Fourier transform infrared (FT-IR) and Raman spectra were recorded and analyzed with the aid of DFT calculations in order to make a suitable assignment of the observed bands. UV-vis spectral analysis was used to determine the band gap energy, and the nonlinear optical (NLO) effect of the compound was predicted using DFT. Further, the title compound exhibits strong fluorescence emission at 394, 329 and 467 nm in the solid at room temperature.
关键词： Nonlinear optical properties,Tetrabromocadmate(II) dianion,Benzyl 4-aminopyridinium,Density functional theory calculation,Crystal structure
更新于2025-09-10 09:29:36