Is BN an appropriate support for metal oxide catalysts
Is BN an appropriate support for metal oxide catalysts
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DOI：
10.1016/j.apcata.2007.03.025
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发表时间：
2007-06
影响因子：
5.5
通讯作者：
G. Postole;G. Postole;A. Gervasini;M. Cǎldǎraru;B. Bonnetot;A. Auroux
中科院分区：
文献类型：
--
作者：
G. Postole;G. Postole;A. Gervasini;M. Cǎldǎraru;B. Bonnetot;A. Auroux
采用溶胶-凝胶法制备了氮化硼负载型金属氧化物(In_2O_3、Ga_2O_3和SnO_2)催化剂。沉积在BN载体上的金属氧化物(15-22wt.%)接近理论单层。采用X-射线衍射仪、X-射线光电子能谱、热重分析、红外光谱、扫描电子显微镜、程序升温还原和吸附微量热法对载体和催化剂进行了表征。对氧化物相与载体表面界面结合的研究表明，在In_2O_3中，氮化硼与客体氧化物之间的结合最强。用NH3和SO2作为碱性和酸性探针对样品进行了吸附微量热实验，结果表明，样品表面以酸中心为主，没有发现真正的碱性。当使用乙酰丙酮金属前驱体时，表面的平均酸强度的顺序为：13In/BN>；17Sn/BN>；19Ga/BN>；BN。选择在高氧气氛中用C2H4选择性还原NO的实验反应，比较了我们的BN负载的氧化物样品和传统陶瓷载体上的相同的氧化物样品。结果表明，活性客体氧化物的沉积改变了BN的力学和化学性能。此外，还证明了BN是一种过于惰性的载体材料，可以帮助这些氧化物很容易地完成NOx还原反应机理。
Boron nitride supported metal oxide (In2O3, Ga2O3and SnO2) catalysts were prepared using a sol–gel method. The amounts of metal oxides (15–22wt.%) deposed on the BN support were close to the theoretical monolayer. The support and the catalysts were characterized by XRD, XPS, TG, IR, SEM, TPR and adsorption microcalorimetry measurements. A study of the interfacial bonding between the oxide phases and the support surface revealed that the bonding between BN and the guest oxide is the strongest for In2O3. The results of adsorption microcalorimetry experiments performed on the samples using NH3and SO2as basic and acidic probes show that acid sites are predominant on their surface, while no real basicity could be evidenced. The mean acid strengths of the surfaces were found to vary in the order: 13In/BN>17Sn/BN>19Ga/BN>BN when using acetylacetonate metallic precursors. The test reaction of selective reduction of NO by C2H4in high oxygen atmosphere was chosen to compare our BN-supported oxide samples with the same oxides supported on conventional ceramic supports. The results showed that the mechanical and chemical properties of BN were altered by the deposition of the active guest oxide. Moreover, it was demonstrated that BN is a too inert support material for assisting these oxides to complete easily a NOxreduction reaction mechanism.