Ambient pressure CO2 hydrogenation over a cobalt/manganese-oxide nanostructured interface: A combined in situ and ex situ study

作者：Gábor Varga, András Sápi, Tamás Róbert Varga, Kornélia Baán, Imre Szenti, Gyula Halasi, Róbert Mucsi, László Óvári, Janos T. Kiss, Zsolt Fogarassy, Bela Pecz, Ákos Kukovecz, Zoltán Kónya · 发表于：Journal of Catalysis · 年份：2020 · DOI：10.1016/j.jcat.2020.03.028 · 被引用次数：67 · 研究领域：Catalysts for Methane Reforming、Catalytic Processes in Materials Science、Carbon Dioxide Capture Technologies

We report on a cobalt/manganese-oxide interface catalyst with outstanding activity and selectivity towards methane even at high temperatures and ambient pressure in CO2 hydrogenation. The catalyst was formed from a MnCo2O4-based spinel structure during the oxidative-reductive pretreatment process just before the catalytic tests. Several Mn-, Fe- and Ni-containing cobaltite spinel and reverse spinel structures were tested to find the best overall performer. The reusable MnCo2O4-based structure featured a CO2 consumption rate of ~8500 nmol*g−1*s−1. Even though methane is not the thermodynamically favoured product, it was produced with ~80% and ~50% selectivity at ambient pressure at 673 K and 823 K, respectively. This unexpected finding is linked to the presence of a unique nanostructured Co/Mn(II)O catalyst with a surface composition of Mn3.3Co2.0O4.7 formed after the pretreatment activation step. Over this phase, the reduction of CO2 progresses through bridge bonded formate located at the Co/Mn2+ interface and this is mostly responsible for high temperature methane formation. This hypothesis is proven here by the reported combination of ex-situ XRD, TPR, HRTEM-ED, HAADF-EDX and in-situ NAP-XPS and DRIFTS techniques.