Catalysis Research Center and Chemistry Department, Technische Universität München, Lichtenbergstrasse 4, 85748 Garching bei München (Germany).
Angew Chem Int Ed Engl. 2014 Jul 1;53(27):7043-7. doi: 10.1002/anie.201400575. Epub 2014 May 21.
Different surface sites of solid catalysts are usually quantified by dedicated chemisorption techniques from the adsorption capacity of probe molecules, assuming they specifically react with unique sites. In case of methanol synthesis catalysts, the Cu surface area is one of the crucial parameters in catalyst design and was for over 25 years commonly determined using diluted N2O. To disentangle the influence of the catalyst components, different model catalysts were prepared and characterized using N2O, temperature programmed desorption of H2, and kinetic experiments. The presence of ZnO dramatically influences the N2O measurements. This effect can be explained by the presence of oxygen defect sites that are generated at the Cu-ZnO interface and can be used to easily quantify the intensity of Cu-Zn interaction. N2O in fact probes the Cu surface plus the oxygen vacancies, whereas the exposed Cu surface area can be accurately determined by H2.
不同的固体催化剂表面位点通常通过专用的化学吸附技术从探针分子的吸附容量来定量，假设它们专门与独特的位点反应。在甲醇合成催化剂的情况下，Cu 表面积是催化剂设计中的关键参数之一，25 多年来一直使用稀释的 N2O 来确定。为了分离催化剂成分的影响，使用 N2O、H2 的程序升温脱附以及动力学实验制备和表征了不同的模型催化剂。ZnO 的存在显著影响 N2O 的测量。这种影响可以通过在 Cu-ZnO 界面处生成的氧缺陷位来解释，并且可以用于容易地定量 Cu-Zn 相互作用的强度。N2O 实际上探测 Cu 表面加氧空位，而暴露的 Cu 表面积可以通过 H2 准确确定。
