Browsing by Author "Lin, HJ"
Now showing 1 - 4 of 4
Results Per Page
Sort Options
- ItemBulk and surface properties regulation of single/double perovskites to realize enhanced oxygen evolution reactivity(John Wiley & Sons, Inc, 2020-04-06) Sun, HS; Hu, B; Guan, DQ; Hu, ZW; Fei, LS; Li, MR; Peterson, VK; Lin, HJ; Chen, CT; Ran, R; Zhou, W; Shao, ZPPerovskite-based oxides have emerged as promising oxygen evolution reaction (OER) electrocatalysts. The performance is closely related to the lattice, electronic, and defect structure of the oxides, which determine surface and bulk properties and consequent catalytic activity and durability. Further, interfacial interactions between phases in a nanocomposite may affect bulk transportation and surface adsorption properties in a similar manner to phase doping except without solubility limits. Herein, we report the development of a single/double perovskite nanohybrid with limited surface self-reconstruction capability as an OER electrocatalyst. Such superior performance arises from a structure that maintains high crystallinity post OER catalysis, in addition to forming an amorphous layer following the self-reconstruction of a single perovskite structure during the OER process. In situ X-ray absorption near edge structure spectroscopy and high-resolution synchrotron-based X-ray diffraction reveal an amorphization process in the hybrid single/double perovskite oxide system that is limited in comparison to single perovskite amorphization, ensuring high catalytic activity. © 2020 Wiley-VCH Verlag GmbH & Co
- ItemDetermination of hole distribution in Sr14-xCaxCu24O41 using soft x-ray absorption spectroscopy at the Cu L3 edge.(American Physical Society, 2013-07-22) Huang, MJ; Deng, G; Chin, YY; Hu, ZW; Cheng, JG; Chou, FC; Conder, K; Zhou, JS; Pi, TW; Goodenough, JB; Lin, HJ; Chen, CTThe physical properties of Sr14-xCaxCu24O41 are determined by the hole distribution between the edge-shared CuO2 chain and the corner-shared Cu2O3 two-leg ladder, but inconsistent results on the hole distribution were obtained in various experimental works in recent decades. In this work we reinvestigate the hole distribution by soft x-ray absorption spectroscopy at the Cu L-3 edge. By comparing with the pure ladder and the pure chain systems, we can unambiguously distinguish between the hole distributions in the chain and the ladder. We have found that there are 5.3 holes in the edge-shared chain and 0.7 holes in the corner-shared ladder on average for Sr14Cu24O41. Upon Ca substitution, the holes gradually transfer from the edge-shared chain to the corner-shared ladder, and there are up to 1.21 holes in the corner-shared ladder for Sr1.8Ca12.2Cu24O41. © 2013, American Physical Society.
- ItemDirect evidence of Ni magnetic moment in TbNi2Mn—X-ray magnetic circular dichroism(Elsevier, 2014-12-01) Yu, DH; Huang, MJ; Su, HC; Lin, HJ; Chen, CT; Campbell, SJ; Wang, JLWe have investigated the individual magnetic moments of Ni, Mn and Tb atoms in the intermetallic compound TbNi2Mn in the Laves phase (magnetic phase transition temperature TC ~131 K) by X-ray magnetic circular dichroism (XMCD) studies at 300 K, 80 K and 20 K. Analyses of the experimental results reveal that Ni atoms at 20 K in an applied magnetic field of 1 T carry an intrinsic magnetic moment of spin and orbital magnetic moment contributions 0.53±0.01 μB and 0.05±0.01 μB, respectively. These moment values are similar to those of the maximum saturated moment of Ni element. A very small magnetic moment of order <0.1 μB has been measured for Mn. This suggests that Mn is antiferromagnetically ordered across the two nearly equally occupied sites of 16d and 8a. A magnetic moment of up to ~0.3 μB has been observed for the Tb atoms. Identification of a magnetic moment on the Ni atoms has provided further evidence for the mechanism of enhancement of the magnetic phase transition temperature in TbNi2Mn compared with TbNi2 (TC~37.5 K) and TbMn2 (TC~54 K) due to rare earth–transition metal (R–T) and transition metal–transition metal (T–T) interactions. The behaviour of the X-ray magnetic circular dichroism spectra of TbNi2Mn at 300 K, 80 K and 20 K – above and below the magnetic ordering temperature TC ~131 K – is discussed. © 2014 Elsevier
- ItemInvestigation of field-induced ferromagnetism in Pd-Ni-Fe-P metallic glass by x-ray magnetic circular dichroism(American Institute of Physics, 2009-01-12) Yu, DH; Duriavig, J; Loh, NA; Woodward, RC; Lin, HJ; Chang, FH; Kilcoyne, SH; Stampfl, APJ; Robinson, RAWe have applied x-ray magnetic circular dichroism to investigate the field-induced ferromagnetism in Pd40Ni22.5Fe17.5P20 alloy. The experiment revealed that both Ni and Fe were in a divalent state and that the magnetic properties of the material were determined by the localized 3d electrons of the transition metals. No clear evidence of Ruderman–Kittel–Kasuya–Yosida-type interaction among magnetic clusters was observed. It is believed that the detailed balance of fundamental spin-orbit and exchange interactions as a function of temperature and applied magnetic field determine the different magnetic properties of the alloy. © 2009, American Institute of Physics