Dreyer Maik, Cruz Daniel, Hagemann Ulrich, Zeller Patrick, Heidelmann Markus, Salamon Soma, Landers Joachim, Rabe Anna, Ortega Klaus Friedel, Najafishirtari Sharif, Wende Heiko, Hartmann Nils, Knop-Gericke Axel, Schlögl Robert, Behrens Malte
Faculty for Chemistry and Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Universitätsstr. 7, 45141, Essen, Germany.
Department of Inorganic Chemistry, Fritz-Haber-Institut der Max-Planck Gesellschaft, Faradayweg 4-6, 14195, Berlin, Germany.
Chemistry. 2021 Dec 6;27(68):17127-17144. doi: 10.1002/chem.202102791. Epub 2021 Nov 8.
Perovskites are interesting oxidation catalysts due to their chemical flexibility enabling the tuning of several properties. In this work, we synthesized LaFe Co O catalysts by co-precipitation and thermal decomposition, characterized them thoroughly and studied their 2-propanol oxidation activity under dry and wet conditions to bridge the knowledge gap between gas and liquid phase reactions. Transient tests showed a highly active, unstable low-temperature (LT) reaction channel in conversion profiles and a stable, less-active high-temperature (HT) channel. Cobalt incorporation had a positive effect on the activity. The effect of water was negative on the LT channel, whereas the HT channel activity was boosted for x>0.15. The boost may originate from a slower deactivation rate of the Co sites under wet conditions and a higher amount of hydroxide species on the surface comparing wet to dry feeds. Water addition resulted in a slower deactivation for Co-rich catalysts and higher activity in the HT channel state.
钙钛矿因其化学灵活性能够调节多种性质而成为有趣的氧化催化剂。在这项工作中，我们通过共沉淀和热分解合成了LaFeCoO催化剂，对其进行了全面表征，并研究了它们在干燥和潮湿条件下的2-丙醇氧化活性，以弥合气相和液相反应之间的知识差距。瞬态测试表明，在转化率曲线中存在一个高活性、不稳定的低温（LT）反应通道和一个稳定、活性较低的高温（HT）通道。钴的掺入对活性有积极影响。水对LT通道有负面影响，而当x>0.15时，HT通道活性增强。这种增强可能源于潮湿条件下钴位点失活速率较慢，以及与干燥进料相比，潮湿进料表面的氢氧化物物种数量更多。添加水导致富钴催化剂失活较慢，且在HT通道状态下活性更高。
