Effect of the Preparation Method of LaSrCoFeOx Perovskites on the Activity of N2O Decomposition
Nia Richards, Luke A. Parker, James Carter, Samuel Pattisson, David Morgan, Nicholas F. Dummer, Stanislaw E. Golunski, Graham J. Hutchings
Abstract
Abstract N 2 O remains a major greenhouse gas and contributor to global warming, therefore developing a catalyst that can decompose N 2 O at low temperatures is of global importance. We have investigated the use of LaSrCoFeO x perovskites for N 2 O decomposition and the effect of surface area, A and B site elements, Co–O bond strength, redox capabilities and oxygen mobility have been studied. It was found that by using a citric acid preparation method, perovskites with strong redox capabilities and weak Co–O bonds can be formed at relatively low calcination temperatures (550 °C) resulting in highly active catalysts. The enhanced activity is related to the presence of highly mobile oxygen species. Oxygen recombination on the catalyst surface is understood to be a prominent rate limiting step for N 2 O decomposition. Here the reduced strength of Co–O bonds and mobile lattice oxygen species suggest that the surface oxygen species have enhanced mobility, aiding recombination, and subsequent regeneration of the active sites. La 0.75 Sr 0.25 Co 0.81 Fe 0.19 O x prepared by citric acid method converted 50% of the N 2 O in the feed (T 50 ) at 448 °C. Graphic Abstract