Fabrication of Ni Nanoparticle-Embedded Porous Carbon Nanofibers Through Selective Etching of Selectively Oxidized MgO

The design of the material synthesis process is important because this process can be applied to a variety of materials and used in different applications. Herein, we selectively oxidized two types of metals in a carbon nanofiber (CNF) support and then left only one type of metal on a porous support using selective etching. Ni and MgO were formed in the CNFs through annealing, and then MgO was etched with an HCl etchant. In the selective oxidation process, two types of metal were selected by considering the oxidation tendency between the metal and C. Ni was selected as an oxidant of C, and Mg was selected as a reductant of C. The two metals with significantly different oxidation tendencies were predicted to have different reactivity with the etchant, making them suitable for selective etching. The effectiveness of selective etching was verified by energy-dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). In EDS, the atomic concentration of Mg was selectively reduced. In TEM, the formation of a porous structure was confirmed. Graphical Abstract: [Figure not available: see fulltext.].