Morphology dependence on anions in hydrothermal synthesis of Co3O4

Abstract

One-dimensional (1D) nanostructures of Co 3 O 4 were synthesized via a mild hydrothermal route. The results of XRD, IR, and TEM revealed a phase transformation was accompanied by the replacement of NO 3 − with CO 3 2− throughout the hydrothermal process. The symmetric types and amount of NO 3 − and CO 3 2− intercalated between the brucite layers played an important role in the formation of nanowires from the hydrothermal system. The amount of CO 3 2− increased as the hydrothermal reaction proceeded. The substitution of CO 3 2− for NO 3 − led to a variation of interlayer forces thus resulted in the instability of intralayer interactions. Therefore, a shape transformation from sheets to wires occurred. Upon calcination, the shapes of precursors were preserved, and 1D nanostructures of Co 3 O 4 resulted.

Kinetic study of the hydrogenation of a monoterpene over spent FCC catalyst‐supported nickel

“…The broad absorption peak at 3150–3520 cm −1 is the stretched vibration of physically adsorbed water, while the bending vibration of physically adsorbed water appears at 1630 cm −1 . The spectrum of Ni/SFCCC absorption peaks at 1390 and 823 cm −1 indicate the presence of NO 3 ‐ and the absorption band for the Si–H stretching vibration is observed at 2350 cm −1 . Additionally, there are no changes in the structure of SFCCC and Ni/SFCCC.…”

A Ni-based catalyst with polyvinyl pyrrolidone as a dispersant supported in a pretreated fluid catalytic cracking catalyst residue for C9 petroleum resin (C9 PR) hydrogenation

“…The bands at 3756 cm −1 , 3652 cm −1 and 1640 cm −1 were assigned to asymmetric stretching, symmetrical stretching and bending vibrations of physically absorbed water. The vibration peaks of NO 3 − at 1382 cm −1 and 823 cm −1 [ 33 ] were not observed, which suggested that the nitrates on the catalyst were completely decomposed after calcination.

Figure 7.

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Effect of anions on the morphology of Co3O4 nanostructures grown by hydrothermal method and their pH sensing application

“…Co3O4 nanocrystals have also been synthesized via a facile combustion method by Feng et al [29]. Beside these several other methods have also been used for the synthesis of spinel Co3O4 nanocrystals such as sol-gel method, polyol process, solvothermal synthesis, polymer assisted synthesis, thermal decompositions, reflux/microwave assisted methods and hydrothermal synthesis for Co3O4 nanorods [30,23,[31][32][33][34][35][36]. All these methods produce high quality nanostructure with different morphologies, but the requirement of high temperature limits the compatibility of growth e.g.…”