Corrosion and transformation of solution combustion synthesized Co, Ni and CoNi nanoparticles in synthetic freshwater with and without natural organic matter

Abstract

Pure metallic Co, Ni, and their bimetallic compositions of Co3Ni, CoNi, and CoNi3 nanomaterials were prepared by solution combustion synthesis. Microstructure, phase composition, and crystalline structure of these nanoparticles (NPs) were characterized along with studies of their corrosion and dissolution properties in synthetic freshwater with and without natural organic matter (NOM). The nanomaterials consisted of aggregates of fine NPs (3–30 nm) of almost pure metallic and bimetallic crystal phases with a thin surface oxide covered by a thin carbon shell. The nanomaterials were characterized by BET surface areas ranging from ~ 1 to 8 m2/g for the Ni and Co NPs, to 22.93 m2/g, 14.86 m2/g, and 10.53 m2/g for the Co3Ni, CoNi, CoNi3 NPs, respectively. More Co and Ni were released from the bimetallic NPs compared with the pure metals although their corrosion current densities were lower. In contrast to findings for the pure metal NPs, the presence of NOM increased the release of Co and Ni from the bimetallic NPs in freshwater compared to freshwater only even though its presence reduced the corrosion rate (current density). It was shown that the properties of the bimetallic nanomaterials were influenced by multiple factors such as their composition, including carbon shell, type of surface oxides, and the entropy of mixing.

Sponge-like CoNi Catalysts Synthesized by Combustion of Reactive Solutions: Stability and Performance for CO2 Hydrogenation

“…The XPS results showed that before the catalysis, the Co concentration on the outermost surface of the SGCS alloy catalysts was higher than that of Ni, even when the stoichiometric ratio of the constituents was kept in a larger volume. A similar trend has been observed in other studies [ 42 ]. However, after the catalysis, the amount of Ni on the surface increased ( Table S1 ).…”

“…Sol-gel combustion synthesis (SGCS) is a unique approach for tailoring the morphology of a material, and allows the fabrication of metallic foams with controlled pore-size distribution [ 42 , 43 , 44 , 45 ]. In this work, we studied the synergetic effect of Co-Ni bonds in bulk Co-Ni alloys on the CO 2 conversion reaction run on sponge-like structural metal catalysts fabricated by SGCS.…”

Insight into nanocrystal synthesis: from precursor decomposition to combustion

“…Nanotechnology-based nanomaterials (NMs) synthesis has attracted the attention of researchers in the modern scientific world compared to that of bulk materials. 1 Improvement in the synthesis approach, along with its crucial outlooks, is the current worldwide consideration, ordinarily, for industrially-scalable applications. Understanding the process from precursor decomposition to nanocrystal formation using advanced instruments allows for controlling the materials' size, morphology, and crystallinity.…”

Synergetic and charge transfer properties of a metal oxide heterojunction: Photocatalytic activities

“…The SG-SCS follows 1) colloidal/sol formations, 2) gel formation by evaporating the water molecules, 3) locally activated combustion reaction (Khort et al, 2021;Novitskaya et al, 2021), 4) propagation along the rest of the media, and 5) finally, the quenching of the reaction by the evolution of gases. Of course, the by-product may further react to the reducing gases/ atmosphere and result in a metal reduction.…”