Effect of Gd-doping in Ni/NiO core/shell magnetic nanoparticles (MNPs) on structural, magnetic, and hydrogen evolution reaction.
J Chem Phys
; 156(6): 064705, 2022 Feb 14.
Article
en En
| MEDLINE
| ID: mdl-35168345
In this study, Gdx-doped Ni/NiO MNPs (x: 0.0%, 2.5%, 5.0%, and 10.0%) with a protective polyvinylpyrrolidone (PVP) layer have been synthesized via a polyol reduction process. The x-ray diffraction patterns revealed that samples have a cubic structure with Fm3Ìm space group and no change in the crystallite structure was observed with doping Gd3+ ions. The crystallite size (Dc) decreases from 2.70 to 1.27 nm when Gd is doped into Ni/NiO MNPs. Transmission electron microscopy analysis revealed that the Ni/NiO MNPs with Gd(5%) concentration are formed as spherical multicore-like shape core/shell MNPs with a protective PVP layer. The magnetic hysteresis measurements taken at 10 and 300 K show that the saturation magnetization (Ms) decreases with increasing Gd3+ ions in the structure. The highest effective magnetic moment (µeff) was obtained as 10.34 µB in the NG-2 sample. We ascribe that the high µeff value in this sample is due to the increase in d-f exchange interaction between Ni(3d7) and Gd(4f7) and the contribution of the dipole moment of PVP molecules. The electrochemical measurements showed that the current density values were 0.294 and 0.319 mA/cm2 at-1.3 V in the absence of Gd (NG-0) and Gd(5%) doped (NG-2) samples, respectively. ßc was 159 and 132 mV/dec for NG-0 and NG-2 samples, respectively. The diminishing of ßc and the charge resistance (Rct) proved that the Gd doped catalyst enhanced the hydrogen evolution activity and the Gd(5%) doped sample exhibited the highest catalyst performance.
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Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
J Chem Phys
Año:
2022
Tipo del documento:
Article
País de afiliación:
Turquía
Pais de publicación:
Estados Unidos