LaXCoO3（X=Mg,Ca,Sr,Ce）催化剂的制备及其催化乙醇水蒸气重整制氢

以PEG 400为分散剂,采用一步柠檬酸络合法制备了LaXCoO3(X=Mg,Ca,Sr,Ce;La:X=3:2)复合催化剂.采用X射线衍射、红外光谱、扫描电镜、X射线光电子能谱、N2吸附-脱附和H2程序升温还原等技术对复合催化剂进行了表征,考察了不同元素A位取代对LaCoO3钙钛矿结构的影响,进而研究了其对乙醇水蒸气重整制氢的催化性能和稳定性.结果表明,在高含量取代时,只有Ce取代的样品能够保持单一的钙钛矿晶型;Ca或Sr取代的样品产生的Co3O4分离相有利于复合催化剂活性中心钴的还原;Sr或Ce取代的样品在反应中表现出较好的活性和稳定性,Sr取代的样品活性更高.

Preparation of LaXCoO3 (X=Mg,Ca, Sr,Ce) catalysts and their performance for steam reforming of ethanol to hydrogen

Perovskite nanocomposite catalysts LaXCoO₃ (X = Mg, Ca, Sr, or Ce; n(La):n(X) = 3:2) have been prepared by a citric acid-complexing method and used for steam reforming of ethanol (SRE), leading to hydrogen generation. The samples were characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, X-ray photoelectron spectroscopy, N₂ adsorption-desorption, and H₂ temperature-programmed reduction. The effects of elemental substitution in the LaCoO₃ perovskite were studied, and the catalytic performance and primary stability of the hydrogen production from SRE were investigated. In the highly substituted samples, only the Ce-doped sample was isolated as the pure perovskite phase. The presence of a Co₃O₄ phase in the Ca-doped or Sr-doped samples was beneficial for the reduction of the active Co component, while Sr-doped or Ce-doped samples showed good activity and stability. The sample incorporating Sr demonstrated better catalytic performance than those of other samples.