Engineering a CoMnOx nanocube core catalyst through epitaxial growth of CoAlOx hydrotalcite shell nanosheets for efficient elimination of propane

Abstract

In this work, we successfully designed a core–shell structured CoMnO_x@Co_xAl₁ catalyst for the catalytic combustion of propane (C₃H₈). Novelly, Al ions were introduced to form CoAl layered double hydroxides (CoAl-LDH) shells at the CoMnO_x interface through a hydrothermal in situ growth domain-limiting mechanism. We observed that the nanocubic core of CoMnO_x derived from the CoMn-PBA precursor and the multilayer hierarchical structure of hydrotalcite CoAlO_x nanosheets were successfully constructed. Considering the effect of the Co/Al molar ratio on the structure of the hydrotalcite shell, we modulated the Co content. Consequently, the activity of the catalyst gradually increased and then decreased with an increase in the Co content. The CoMnO_x@Co_xAl₁ catalysts showed higher activity, stability and water resistance than CoMnO_x. The TOF_(Co+Mn) of CoMnO_x@Co_xAl₁ was much higher than that of CoMnO_x at 220 °C. Strong interactions at the core–shell interface significantly increased the oxygen activation capacity and oxygen mobility, which accelerated the cleavage of the C–H bond and significantly improved the catalytic performance. DFT calculations reveal that CoMnAlO₄ with (100) planes possesses outstanding adsorption and activation capabilities for C₃H₈. TPSR confirmed the distribution of the reaction products, identifying the final products as CO₂ and H₂O. This efficient and stable catalytic system offers valuable insights for designing high-performance catalysts aimed at the complete decomposition of C₃H₈.