Nucleation and Growth of Magnetic Ni−Co (Core−Shell) Nanoparticles in a One-Pot Reaction under Microwave Irradiation

Abstract

SI-1. InstrumentsUV-vis spectra were obtained using a V-570 spectrometer (JASCO CO.). 1 H NMR spectra were recorded using a Joel jnm-GSX400 (400 MHz). The measurement was taken in CDCl 3 using tetramethylsilane (TMS) as an internal standard. SI-2. Yield of Ni 50 Co 50Yield of Ni 50 Co 50 was calculated from the weight of the obtained powder. Ni 2+ (12.5 mmol) and Co 2+ (12.5 mmol) were used for the synthesis of Ni-Co nanoparticles. The composition in the obtained powder was confirmed as Ni 50 Co 50 from the ICP results. The weight of the obtained powder was 1.56 g. The weight percent of the surface modifying agents in the powder was 6.0 wt%, determined by TGA. Therefore, the yield of Ni 50 Co 50 -the amounts of Ni and Co atoms-was 99.5

Synthesis and Structural Evolution of Nickel-Cobalt Nanoparticles Under H2and CO2

“…This second step used a Co(0) precursor, thus avoiding any galvanic reaction that would release metal cations into the solution. In contrast with other synthetic routes such as the one developed by Yamauchi et al, our protocol did not require the reduction of the cobalt precursor because it was already at the zero oxidation state. Upon addition to the Ni(0) NPs solution, Co 2 (CO) 8 dissolves and produced a bubbling of gas.…”

Thermal Stability of Core–Shell Nanoparticles: A Combined in Situ Study by XPS and TEM

“…The high cost of noble metals has renewed interest in utilizing inexpensive first-row transition metals (Fe, Co, Ni, etc. ), even though NPs preparation with these metals presents a challenge due to their greater negative redox potential 11 .…”

“…Besides, transition metal core-shell NPs have revealed novel physical properties approaching those of noble metals [11][12][13] . Because of this, the potential for greater catalytic activity and selectivity from core-shell NPs compared to monometallic NPs is a strong motivation for studying core-shell configurations of bimetallic NPs.…”

Unusual Effect of Trace Water on the Structure and Activity of NixCo1−x Electrocatalysts for the Methanol Oxidation Reaction

“…Various synthetic methods have been proposed, such as the microemulsion method, microwave radiation synthesis, polyol reduction, and electrodeposition, which are effective for the preparation of nickel‐based catalysts with various morphologies and anisotropy, for example, Ni–Co nanoflowers, nanoneedles, self‐assembled Ni–Co nanoparticles, dendrite‐like Ni–Cu alloy, and Ni–Co–Sn alloy nanoparticles . Cu/NiCu nanowires synthesized by the microemulsion method showed much higher activities than nickel nanoparticles in oxidizing methanol .…”