Greluk Magdalena, Rotko Marek, Słowik Grzegorz, Turczyniak-Surdacka Sylwia, Grzybek Gabriela, Tyszczuk-Rotko Katarzyna
Department of Chemical Technology, Faculty of Chemistry, Maria Curie-Sklodowska University in Lublin, Maria Curie-Sklodowska Sq. 3, 20-031 Lublin, Poland.
Biological and Chemical Research Centre, University of Warsaw, 101 Żwirki i Wigury Street, 20-089 Warsaw, Poland.
Materials (Basel). 2023 Jul 31;16(15):5377. doi: 10.3390/ma16155377.
The promotional effect of potassium (~1.25 wt%) on a Co/MnO catalyst was studied for samples prepared by the impregnation method in the steam reforming of ethanol (SRE) process at 420 °C for a HO/EtOH molar ratio of 12/1. The catalysts were characterized using physicochemical methods to study their textural, structural, and redox properties. The XRD studies revealed that, during the treatment of both cobalt-based catalysts under a hydrogen atmosphere at 500 °C, Co and MnO phases were formed by the reduction in CoO and MnO/MnO phases, respectively. Potassium doping significantly improved stability and ability for the C-C bond cleavage of the Co/MnO catalyst. The enhancement of activity (at ~25%) and selectivity to hydrogen (at ca. 10%) and the C1 product, mainly carbon dioxide (at ~20%), of the Co/MnO catalyst upon potassium doping was clarified by the alkali promoter's impact on the reducibility of the cobalt and manganese oxides. The microscopic observations revealed that fibrous carbon deposits are present on the surface of Co/MnOx and KCo/MnOx catalysts after the SRE reaction and their formation is the main reason these catalysts deactivate under SRE conditions. However, carbon accumulation on the surface of the potassium-promoted catalyst was ca. 12% lower after 18 h of SRE reaction compared to the unpromoted sample.
研究了钾（约1.25 wt%）对通过浸渍法制备的Co/MnO催化剂的促进作用，该催化剂用于乙醇蒸汽重整（SRE）过程，反应温度为420℃，H₂O/EtOH摩尔比为12/1。采用物理化学方法对催化剂进行表征，以研究其织构、结构和氧化还原性能。XRD研究表明，在500℃氢气气氛下处理两种钴基催化剂时，CoO和MnO/MnO₂相分别还原形成Co和MnO相。钾掺杂显著提高了Co/MnO催化剂的稳定性和C-C键断裂能力。通过碱促进剂对钴和锰氧化物还原能力的影响，阐明了钾掺杂后Co/MnO催化剂活性（提高约25%）、对氢气的选择性（提高约10%）和对C1产物（主要是二氧化碳，提高约20%）的增强作用。微观观察表明，SRE反应后Co/MnOx和KCo/MnOx催化剂表面存在纤维状碳沉积物，其形成是这些催化剂在SRE条件下失活的主要原因。然而，与未促进的样品相比，SRE反应18小时后，钾促进催化剂表面的碳积累量降低了约12%。
