Porous hollow CoInOx nanocubes as a highly efficient catalyst for the catalytic combustion of toluene

Abstract

Porous hollow HC-CoInOx nanocubes were synthesized via a SiO₂ template strategy involving a cobalt-based metal–organic framework derived from a Prussian Blue analogue. As a heterogeneous catalytic material for the catalytic combustion of toluene, the hollow HC-CoInOx nanocubes displayed superior catalytic performance (T₉₀ = 178 °C) and greatly reduced the activation energy for toluene oxidation due to their large surface area, the formation of surface dangling bands and oxygen vacancies, and increased number of weak acid sites. In comparison, the C-CoInOx sample (without the introduction of a SiO₂ template) required a higher reaction temperature to achieve the same conversion of toluene (T₉₀ = 345 °C). Especially, the insertion and coating of SiO₂ in CoIn-PBA nanocubes greatly improves their thermal stability, and the nanocubic shape of the porous hollow HC-CoInOx sample can remain intact after roasting at 450 °C, while the nanocubic shape of the C-CoInOx sample without the introduction of SiO₂ is partially damaged and suffers from serious aggregation under the same firing conditions. Simultaneously, the porous hollow HC-CoInOx nanocubes also exhibited excellent cycling and thermal stability for the catalytic combustion of toluene to CO₂ and H₂O.