LaAl12O19 hexaaluminate was prepared by reverse microemulsion method in the water/TritonX-100/n-butoanol/cyclohexane. LaMAl11O19 were prepared using transition-metal M(M=Fe,Co) to substitute Al in the hexaaluminate la...LaAl12O19 hexaaluminate was prepared by reverse microemulsion method in the water/TritonX-100/n-butoanol/cyclohexane. LaMAl11O19 were prepared using transition-metal M(M=Fe,Co) to substitute Al in the hexaaluminate lattice with same method. The LaAl12O19 hexaaluminate and effects of M on phase composition, specific surface area and activities evaluation for methane combustions were investigated by means of XRD, BET, H2-TPR and eatalytic reaction of methane combustion. Reverse microemulsion method is beneficial to maintain high surface area. The specific surface areas of prepared catalysts have about 11.6～16.3 m2·g-1. XRD spectrum analysis of Co-doping and no-doping catalyst indicated that hexaaluminate phase catalysts were dominated and companied with few perovskite phase when calcined at 1 400 ℃ for 3 hours. H2-TPR profiles of the Fe-doping and Co-doping catalysts showed that the reduction peaks appeared in the range of 400 ℃ and 800 ℃, instead of that there weren’t any reduction peaks of no-doping catalyst. Compared with no-doping catalyst, not only the high-temperature activity of Fe-doping and Co-doping catalysts increased obviously, but also was methane half conversion temperature below 700 ℃ and was methane complete conversion temperature at 800 ℃. However, the high-temperature activity of Fe-doping catalyst is better than Co-doping catalyst within 700 ℃, and theirs the high-temperature activity are almost same over 700 ℃. Fe-doping catalyst formed single phase of hexaaluminate LaFeAl11O19.展开更多
文摘LaAl12O19 hexaaluminate was prepared by reverse microemulsion method in the water/TritonX-100/n-butoanol/cyclohexane. LaMAl11O19 were prepared using transition-metal M(M=Fe,Co) to substitute Al in the hexaaluminate lattice with same method. The LaAl12O19 hexaaluminate and effects of M on phase composition, specific surface area and activities evaluation for methane combustions were investigated by means of XRD, BET, H2-TPR and eatalytic reaction of methane combustion. Reverse microemulsion method is beneficial to maintain high surface area. The specific surface areas of prepared catalysts have about 11.6～16.3 m2·g-1. XRD spectrum analysis of Co-doping and no-doping catalyst indicated that hexaaluminate phase catalysts were dominated and companied with few perovskite phase when calcined at 1 400 ℃ for 3 hours. H2-TPR profiles of the Fe-doping and Co-doping catalysts showed that the reduction peaks appeared in the range of 400 ℃ and 800 ℃, instead of that there weren’t any reduction peaks of no-doping catalyst. Compared with no-doping catalyst, not only the high-temperature activity of Fe-doping and Co-doping catalysts increased obviously, but also was methane half conversion temperature below 700 ℃ and was methane complete conversion temperature at 800 ℃. However, the high-temperature activity of Fe-doping catalyst is better than Co-doping catalyst within 700 ℃, and theirs the high-temperature activity are almost same over 700 ℃. Fe-doping catalyst formed single phase of hexaaluminate LaFeAl11O19.
