Ce–Mn coordination polymer derived hierarchical/porous structured CeO2–MnOx for enhanced catalytic properties

Abstract

Catalytic performance is largely dependent on how the structures/compositions of materials are designed. Herein, CeO₂–MnO_x binary oxide catalysts with a hierarchical/porous structure are prepared by a facile and efficient method, which involves the preparation of the hierarchical Ce–Mn coordination polymer (CPs) precursor, followed by a thermal treatment step. The obtained CeO₂–MnO_x catalysts not only well inherit the hierarchical structure of Ce–Mn CPs, but also possess porous and hollow features due to the removal of organic ligands and heterogeneous contraction during the calcination process. In addition, the effect of the Mn/Ce ratio is also studied to optimize catalytic performance. Specifically, the as-prepared CeO₂–MnO_x (5 : 5) catalyst exhibits excellent catalytic performance toward CO oxidation and selective catalytic reduction (SCR) of NO with NH₃ at low temperatures. Based on the characterization results, we propose that the special hierarchical structure, high surface area, strong synergistic interaction between CeO₂ and MnO_x, and high content of active Ce³⁺, Mn⁴⁺ and O_surf are collectively responsible for its remarkable catalytic performance.