| Abstract
| - Low-temperature synthesis of spinels MgxCo1-xCo2O4 (x = 0.0−0.9) has been investigatedwith two important synthetic parameters and XRD/FTIR/DSC/BET/ICP/CHN methods. Itis found that with an increase in hydrothermal treatment temperature, precursor compoundschange from the hydrotalcite-like to brucite-like and then to cubic spinel phase when theinitial metal concentration ratio [Mg2+]:[Co2+] ≥ 1, while from the turbostratic to hydrotalcite-like and then to cubic spinel phase when the [Mg2+]:[Co2+] < 1. The MgxCo1-xCo2O4 (x ≤ 1/3)spinels were formed at temperatures as low as 50−100 °C. In the postsynthesis thermaltreatment, various thermal events have been observed, and in all cases the spinel phasecan be prepared at temperatures below 300 °C. On the basis of FTIR results, a topotacticmechanism for the formation of the spinel phase has been confirmed. Specific surface areaas high as 210 m2/g has been attained in 400 °C calcined MgxCo1-xCo2O4 with x = 0.9. Causesfor the formation of the spinel phase at low temperatures have been addressed. Excellentcatalytic activity for N2O decomposition (30.6−38.9 mmol (N2O)/g·h at GHSV = 21200 h-1and 380−400 °C; N2O = 10 mol % balanced with He) has been observed and discussed forthese Mg−Co spinels.
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