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用 IR光谱研究了 SO2 -4 / Fe2 O3- Al2 O3纳米固体酸在不同焙烧温度下表面结构与酸性的变化 ,结果表明 ,当焙烧温度在 4 5 0— 5 0 0℃时 ,双齿螯合配位结构特征谱带齐全 ,酸性强 ,小于 4 5 0℃时 ,双齿螯合配位特征谱带不齐全 ,酸性不强 ,而大于 5 0 0℃时 ,随着温度的升高 ,特征谱带区域宽化 ,特征峰消失 ,酸性变弱。此外 ,从 Fe- O纳米颗粒的特征振动带显示可得知 ,样品的粒径小于 30 nm。
The changes of surface structure and acidity of SO2-4 / Fe2O3-Al2O3 nanosolid acid at different calcination temperatures were investigated by IR spectra. The results showed that when the calcination temperature was between 450 and 500 ℃, bidentate chelation The coordination band has the characteristic bands of complete structure and strong acidity. When the temperature is below 450 ℃, the chelate coordination characteristic bands of the bidentate are not complete and the acidity is not strong. When the temperature is above 500 ℃, the characteristic Broadening of the band region, the disappearance of the characteristic peak, weakening of the acidity. In addition, the characteristic vibrational band of Fe-O nanoparticles shows that the particle size of the sample is less than 30 nm.