Thermal behaviour, surface properties and vibrational spectroscopic studies of the synthesized Co3xNi3−3x(PO4)2·8H2O (0 ≤ x ≤ 1)

•The simple synthetic route of Co3xNi3−3x(PO4)2·8H2O; x = 1, 0.8, 0.6, 0.4, 0.2 and 0 at low temperature was reported.•Co3xNi3−3x(PO4)2, x = 0.8 exhibited highest surface area among the studied hydrates and anhydrous compounds.•Thermal properties and detailed vibrational spectroscopic data of the title compounds are reported for the first time.

Co3xNi3−3x(PO4)2·8H2O (x = 1, 0.8, 0.6, 0.4, 0.2, and 0) were synthesized via simple wet chemical reaction and energy saving route method. The final decomposition products of hydrates are corresponding anhydrous tri(cobalt nickel) diphosphates. The metal and water contents of the synthesized hydrates were confirmed by AAS and TG/DTG/DTA techniques, respectively. The observed metal and water contents agree well with the formula of the title compounds. The crystal structures and lattice parameters as well as crystallite sizes of the studied compounds were determined using XRD data. The results from XRD and TG/DTG/DTA techniques confirmed that Co3xNi3−3x(PO4)2·8H2O at all ratios were the single phase. The FTIR spectra of studied compounds were recorded and assigned. The thermal behaviours of single and binary tri(cobalt nickel) diphosphate octahydrates were studied for the first time. The morphologies of the studied compounds were investigated by using the SEM technique. The micrographs of all studied compounds exhibited the thin plated morphology. The surface area and the pore size data of anhydrous forms were measured by N2 adsorption at −190 °C according to the BET method. The anhydrous forms of binary metal phosphate at x = 0.8, Co2.4Ni0.6(PO4)2, exhibits the highest surface area and expects to improve the catalytic activity.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide