Mesoporous NiCo2O4 Spinel: Influence of Calcination Temperature over Phase Purity and Thermal Stability

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• 作者：Moiss Cabo ; Eva Pellicer ; Emma Rossinyol ; Onofre Castell ; Santiago Suriach ; Maria Dolors Bar
• 刊名：Crystal Growth & Design
• 出版年：2009
• 出版时间：November 4, 2009
• 年：2009
• 卷：9
• 期：11
• 页码：4814-4821
• 全文大小：1208K
• 年卷期：v.9,no.11(November 4, 2009)
• ISSN：1528-7505

文摘

Mesoporous NiCo₂O₄ spinel has been synthesized by nanocasting, using SBA-15 and KIT-6 silica as hard templates. Two temperatures of calcination were applied for the conversion of the spinel precursors (metal nitrates) into NiCo₂O₄. At 375 °C the pure spinel was obtained, whereas at 550 °C NiO impurities were detected. The mesoporous powders obtained were characterized by transmission electron microscopy, X-ray diffraction, Brunauer−Emmett−Teller analysis, and magnetic measurements. In addition, their thermal stability was assessed by post heat-treating the materials at 550 °C: the mesostructure of the pure spinel (calcined at 375 °C) collapsed, leading to the disruption of the porous network, while the mesoporosity of the powders calcined at 550 °C was preserved. In all cases, the post-thermal treatment induced the segregation of NiO; the final NiO amount was found to be in the 7−10 wt % range.