Performance of an aliovalent-substituted CoCeOx catalyst from bimetallic MOF for VOC oxidation in air

Abstract

The aliovalent-substitution of cobalt into ceria lattice was demonstrated using a bimetallic CoCeBDC MOF to achieve a high degree of atomic level mixing in the CoCeOx catalyst. Spectroscopic analyses including X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and time-of-flight secondary ion mass spectrometry (ToF-SIMS) confirmed the successful insertion of cobalt atom with a concomitant increase in defects (i.e., Raman ID/IF2g = 0.25) and oxygen vacancies (i.e., XPS Oβ/(Oα+Oβ) = 0.33) that correlates well with catalytic activity for the oxidations of methanol, acetone, toluene, and o-xylene. The as-prepared CoCeOx performed a 50% conversion (T50) and 90% conversion (T90) in toluene oxidation at 212 °C and 227 °C that are significantly lower than the reference Co3O4/CeO2 nanocube catalyst that had T50 of 261 °C and T90 of 308 °C, indicating its better catalytic activity. Moreover, CoCeOx catalyst completely oxidizes organic compounds to carbon dioxide and water, while reaction over Co3O4/CeO2 nanocube catalyst produces significant carbon monoxide.