摘要
Cu-based mixed oxides (Cu<sub>xsub>Mg<sub>3鈭?/sub><sub>xsub>AlO-800s, x = 0, 0.5, 1.0, 1.5, 2.0 and 3.0) were prepared by calcinations of corresponding Cu<sub>xsub>Mg<sub>3鈭?/sub><sub>xsub>Al ternary hydrotalcites (Cu<sub>xsub>Mg<sub>3鈭?/sub><sub>xsub>Al-HTLCs) at 800 掳C and used for catalytic combustion of propane. The Cu<sub>xsub>Mg<sub>3鈭?/sub><sub>xsub>Al ternary hydrotalcites and derived combustion catalysts were well characterized to investigate the dependence of the performance of propane catalytic combustion with their structure and components. The results showed that Cu can replace Mg in a wide range of Cu/Mg ratios to form Cu<sub>xsub>Mg<sub>3鈭?/sub><sub>xsub>Al-HTLCs with the unique layered structure of hydrotalcite, though the Cu substitution significantly deteriorates the thermal stability of the Cu<sub>xsub>Mg<sub>3鈭?/sub><sub>xsub>Al-HTLCs. It was found that calcinations at 800 掳C completely transformed the Cu<sub>xsub>Mg<sub>3鈭?/sub><sub>xsub>Al-HTLCs to Cu<sub>xsub>Mg<sub>3鈭?/sub><sub>xsub>AlO-800 mixed oxides, containing spinel, periclase and tenorite oxide phases. The TPR results revealed those catalysts derived from hydrotalcites were easier to be reduced than the simply mixed oxides, this was due to the strong interactions among the components existing in the Cu<sub>xsub>Mg<sub>3鈭?/sub><sub>xsub>AlO-800 materials. The Cu<sub>xsub>Mg<sub>3鈭?/sub><sub>xsub>AlO-800 catalysts exhibit superior catalytic activity in propane combustion to Pd/Al<sub>2sub>O<sub>3sub> and the mechanically mixed oxides. The excellent activities of the Cu<sub>xsub>Mg<sub>3鈭?/sub><sub>xsub>AlO-800 were attributed to the strong interaction among the component oxides as observed by the XRD, TG-DSC and TPR characterizations.