Inverse Coprecipitation Directed Porous Core–Shell Mn–Co–O Catalyst for Efficient Low Temperature Propane Oxidation

Abstract

Mn–Co–O catalysts with different Mn/Co molar ratios were synthesized by means of a facile inverse coprecipitation strategy and applied for the oxidation of propane (C3H8). The XRD pattern of Co2Mn1Oδ (molar ratio of Mn:Co = 1:2) indicates a Co3O4 phase, and most Mn incorporates into Co3O4 lattice to form a solid solution. Minor distributed Mn species occur structure reforming, totally converting to a stable Co–Mn solid solution during oxidation process. Meanwhile, Co2Mn1Oδ features a porous core–shell morphology, the core and shell of which are made up of Co–Mn solid solution, giving rise to a high surface area. The optimized synergistic effect of manganese and cobalt improves low temperature reducibility and produces rich surface active Co3+ species and surface-absorbed oxygen over Co2Mn1Oδ. As a result, it exhibits a prominent excellent catalytic activity, and delivers good thermal stability in the presence of 5 vol % H2O and 5 vol % CO2. In situ DRIFTs analysis displays the reaction path of C3H8 over Co2Mn1Oδ, where dominate intermediate species formate are easily decomposed into CO2. The synthesized porous core–shell Mn–Co–O can be a promising candidate replacing non-noble catalysts toward C3H8 oxidation at low temperature.