The bimessite and cryptomelane types of manganese oxide were prepared by the sol-gel method using KMnO_4 and glucose. The rnoptimum conditions were investigated by varying different process variables such as c(glucose)/c(KMnO_4) ratio, calcination temperature, reaction time, and gel treatment methods. The results of X-ray diffraction and atomic absorption spectroscopy indicated that the crystal phases of manganese oxide were controllable with different gel treatment methods. Under the conditions of c(glucose)/c(KMnO_4) = 0.74, t=20 s and by different gel treatment methods, the bimessite and cryptomelane with high purity and high crystallinity were synthesized. The catalytic performance of both types of manganese oxide for the combustion of dimethyl ether was excellent, but the cryptomelane showed much higher catalytic activity than the birnessite.%以葡萄糖和高锰酸钾为原料,采用溶胶-凝胶法合成了birnessite(K_(1.35)MnO_2,简写为Bir)和cryptomelane(K_(0.27)MnO_2,简写为Cry)型氧化锰;采用X射线衍射、原子吸收光谱等考察了凝胶处理方法、反应物浓度比、焙烧温度和反应时间等对氧化锰晶型的影响.结果表明,采用不同方法处理凝胶可实现对Bir和Cry型氧化锰的可控合成.以不同的处理方法,葡萄糖和高锰酸钾的浓度比为O.74,反应20s制成凝胶,并在400℃焙烧2h,可分别制取高结晶度和高纯度的Bir和Cry型氧化锰.Bir和Cry型氧化锰在二甲醚燃烧反应中表现出优异的催化性能,且Cry型氧化锰的催化活性更高.
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