Publications by authors named "Chong-Chi Chi"

High-entropy-alloy (HEA) nanocrystals hold immense potential for catalysis, offering virtually unlimited alloy combinations through the inclusion of at least five constituent elements in varying ratios. However, general and effective strategies for synthesizing libraries of HEA nanocrystals with controlled surface atomic structures remain scarce. In this study, a transferable strategy for developing a library of facet-controlled seed@HEA nanocrystals through seed-mediated growth is presented.

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Rechargeable zinc-air batteries (ZABs) are viewed as a promising solution for electric vehicles due to their potential to provide a clean, cost-effective, and sustainable energy storage system for the next generation. Nevertheless, sluggish kinetics of the oxygen evolution reaction (OER), the oxygen reduction reaction (ORR) at the air electrode, and low power density are significant challenges that hinder the practical application of ZABs. The key to resolving the development of ZABs is developing an affordable, efficient, and stable catalyst with bifunctional catalytic.

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We report a catalyst family of high-entropy alloy (HEA) atomic layers having three elements from iron-group metals (IGMs) and two elements from platinum-group metals (PGMs). Ten distinct quinary compositions of IGM-PGM-HEA with precisely controlled square atomic arrangements are used to explore their impact on hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR). The PtRuFeCoNi atomic layers perform enhanced catalytic activity and durability toward HER and HOR when benchmarked against the other IGM-PGM-HEA and commercial Pt/C catalysts.

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High-entropy alloy (HEA) nanocrystals have attracted extensive attention in catalysis. However, there are no effective strategies for synthesizing them in a controllable and predictable manner. With quinary HEA nanocrystals made of platinum-group metals as an example, we demonstrate that their structures with spatial compositions can be predicted by quantitatively knowing the reduction kinetics of metal precursors and entropy of mixing in the nanocrystals under dropwise addition of the mixing five-metal precursor solution.

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In this study, the high-density SiC/SiO core-shell nanowires were synthesized on the nickel coated SiO (100 nm)/Si substrate by chemical vapor deposition (CVD) method with ferrocene precursor at temperature 1000 °C compared to previous studies (1300-1600 °C). The present work provides an efficient strategy for the production of SiC/SiO nanowires with uniform morphology and good optical properties, where the Ni layer plays important roles for this fabrication at low temperature which reduces the decomposition temperature of hydrocarbon gases and improves the growth quality of SiC nanowires. The as-synthesized SiC/SiO nanowires consist of single crystal 3C structures as well as 3C structures with defects along [111] direction.

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Article Synopsis
  • Nanoelectronics using two-dimensional (2D) materials face challenges due to contact issues with semiconducting monolayers, particularly in creating p-type transistors with low Schottky barriers.
  • Tungsten selenides (WSe) have shown promise for p-type transistors but require high growth temperatures, which can lead to inconsistencies.
  • This study demonstrates a method to grow WSe at a reduced temperature of 800°C using a seeding promoter and low-pressure chemical vapor deposition, resulting in high-quality interfaces with graphene, characterized by transmission electron microscopy (TEM).
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The multilayer 1T-TaSe is successfully synthesized by annealing a Se-implanted Ta thin film on the SiO/Si substrate. Material analyses confirm the 1T (octahedral) structure and the quasi-2D nature of the prepared TaSe. Temperature-dependent resistivity reveals that the multilayer 1T-TaSe obtained by our method undergoes a commensurate charge-density wave (CCDW) transition at around 500 K.

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