Bimetallic core-shell nanoparticles (BCSNPs) usually exhibit marvelous electronic, magnetic, and catalytic properties comparing with respective bulks. In this research, we systematically studied 13- 33- and 55-atoms Co-Ni core-shell nanoparticles. The basic physical properties such as structure stability, thermodynamic stability, electronic, magnetic, and the chemical catalytic activity of hydrogen evolution reaction (HER) were performed by DFT calculation. The results showed that Ni atoms in the surface-shell are more thermodynamically favorable than Co atoms Co-Ni BCSNPs. Interestingly, for 13- 33- and 55-atoms BCSNPs, three-shell BCSNPs are more stable than two-shell. The Ni surface-shell of the Co@Ni BCSNPs displayed a positive charge attributed to the charge transfer in the Co-Ni BCSNPs, resulting in that the d-band center of Co@Ni with the Ni surface-shell showed a more significant shift toward the Fermi level and higher chemical activity. We found that Co-Ni nanoparticles have adjustable magnetic moments which can be adjusted by changing the location of Co and Ni atoms in the Co-Ni clusters. In addition, an interesting trend was found in HER activity: The hydrogen adsorption free energy (ΔGH*) increases with the number of cluster atoms. All 13-atoms NPs and BCSNPs showed a negative ΔGH*, while 33 and 55-atoms NPs and BCSNPs showed a positive ΔGH*, indicating that the best configuration of the Co-Ni NPs and BCSNPs for hydrogen evolution reaction is 13~33 atoms. The results will help to provide a certain theoretical basis and guidance for its controllable synthesis of Co-Ni NPs, BCSNPs and the design of excellent HER cluster catalysts.

Computational Investigation of Co-Ni Core-shell Nanoparticles: A systematic study of geometry structure, electronic, magnetic, and catalytic properties

ACS Spring Meeting 2021

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