Preparation of CuxCo1-x/Al2O3/Cordierite Monolithic Catalysts and the Catalytic Combustion of Toluene

Abstract

A series of Cu x Co 1- x /Al 2 O 3 /cordierite ( x = 0–1) catalysts were prepared using cordierite as a support, a boehmite primer sol as the first washcoat layer and copper as well as cobalt oxides as the activity washcoat layer. The structure of the catalysts was characterized using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and temperature-programmed reduction. Toluene was chosen as a model compound to evaluate the catalytic activity in a conventional fixed-bed quartz reactor. The results indicate that Cu-Co-O was present when the Cu content was low. CuO diffraction peaks were observed when the Cu content was high. Both Co 2+ and Co 3+ exist on the surface of the obtained monolithic catalysts while Cu 2+ is the main Cu species. The addition of a certain amount of copper oxide improved the reducibility of the cobalt oxide, which enhanced the catalytic activity of the catalysts. All the obtained catalysts showed good activity for the catalytic combustion of toluene. The Cu 0.5 Co 0.5 /Al 2 O 3 /cordierite catalyst showed the best catalytic activity. Toluene was completely oxidized at 315 °C. 摘要：以堇青石蜂窝陶瓷为基底, Al 2 O 3 浆料为过渡胶体, Cu 和 Co 为催化活性组分, 制备了一系列 Cu x Co 1- x /Al 2 O 3 /堇青石 ( x = 0−1) 整体式催化剂. 采用 X 射线衍射、X 射线光电子能谱、扫描电镜和程序升温还原等手段对催化剂进行了表征. 以甲苯为模型化合物, 在微型固定床反应器上评价了催化剂的催化性能. 结果表明, 当 Cu 含量较低时, 在整体式催化剂上形成了Cu-Co-O 固溶体; 当 Cu 含量较高时, 可以检测到 CuO. 在催化剂表面, Co 以 Co 2+ 和 Co 3+ 形式存在, 而 Cu 主要以 Cu 2+ 形式存在. 适量 Cu 的加入可以改善催化剂中 Co 的氧化还原性能, 有利于催化剂活性的提高. 在所制备的催化剂中, Cu 0.5 Co 0.5 /Al 2 O 3 /堇青石整体式催化剂活性最高, 在315 o C 可以完全催化燃烧消除甲苯. Cu x Co 1- x /Al 2 O 3 /cordierite monolithic catalysts were prepared and their catalytic performance during toluene combustion was evaluated. The catalysts show good activity for the catalytic combustion of toluene.