Efficient synthesis of Co2+–Co3+ hydrotalcite-like compounds via NaOH precipitation in methanol–water under mild alkaline conditions

Divalent/trivalent cobalt hydrotalcite-like compounds (Co2+–Co3+ HTlc) were synthesized via precipitation under mild alkaline conditions by using NaOH as precipitant and methanol–water as solvent. The influences of synthetic parameters including CH3OH:H2O volume ratio, precipitation pH, and hydrothe...

Full description

Saved in:
Bibliographic Details
Published in:Applied clay science 2023-02, Vol.232, p.106807, Article 106807
Main Authors: Wan, Chunsheng, Xie, Guanbao, Zhang, Meng, Huang, Hongyang, Li, Dalin, Jiang, Lilong
Format: Article
Language:English
Subjects:
Cobalt
Hydrotalcite-like compounds
Methanol–water
Oxidative intercalation
Precipitation
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Divalent/trivalent cobalt hydrotalcite-like compounds (Co2+–Co3+ HTlc) were synthesized via precipitation under mild alkaline conditions by using NaOH as precipitant and methanol–water as solvent. The influences of synthetic parameters including CH3OH:H2O volume ratio, precipitation pH, and hydrothermal treatment on the HTlc formation were investigated. The crystalline phase, morphology, and chemical composition of the synthesized samples were characterized by XRD, FTIR, SEM, TG–MS, and iodometric titration. The formation of Co2+–Co3+ HTlc was strongly affected by the methanol content and a single Co2+–Co3+ HTlc phase was obtained by raising the CH3OH:H2O ratio to 4:1–8:1. It was suggested that the presence of methanol increased the concentration of dissolved oxygen and promoted the oxidation of Co2+ into Co3+, leading to complete transformation of α-Co(OH)2 into Co2+–Co3+ HTlc. Moreover, single-phased Co2+–Co3+ HTlc was available at pH between 10 and 12, and they were hydrothermally stable by treatment at 60 °C for 24 h. Under the synthetic conditions, complete precipitation of cobalt ions was achieved. This highlights that the developed synthesis process is an efficiency way for quantitative synthesis of cobalt HTlc. [Display omitted] •Co2+–Co3+ HTlcs are synthesized by NaOH precipitation in methanol–water.•A single Co2+–Co3+ HTlc phase is formed at CH3OH:H2O ratio of 4:1–8:1.•Single-phased Co2+–Co3+ HTlc are available at pH = 10–12.•Complete precipitation of Co2+ is achieved under the synthesis conditions.
ISSN:0169-1317
1872-9053
DOI:10.1016/j.clay.2022.106807