Hydrothermal synthesis of β-Co(OH)2 nanoplatelets: A novel catalyst for CO oxidation.

A facile, cost-effective, template-free chemical method was developed for the synthesis of β -Co(OH) 2 nanoplatelets under the different preparation conditions. The morphology and microstructure of as-synthesized samples were examined by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectrum (XPS), respectively. The observations revealed the formation of a single phase of the hexagonal brucite-like β -Co(OH) 2 , which had an irregular hexagonal disk with angles of adjacent edges of 120°, edge lengths ranging from 200 to 300 nm, and thicknesses of 20–40 nm. When investigated as catalyst for CO oxidation, the β -Co(OH) 2 nanoplatelets exhibited good catalytic activity for CO. Among β -Co(OH) 2 nanoplatelets, the sample prepared at 100 °C for 8 h performed the best, giving the T 100% (the temperature required for achieving a CO of 100%) of 120 °C for the oxidation of CO. There are good correlations of Co 3+ /Co 2+ , the absorbed O x − ions and surface OH group with catalytic activity of the samples for CO oxidation. [ABSTRACT FROM AUTHOR]