Constructing oxygen vacancy induced Fe-Mn-Cu mixed oxides for efficient catalytic combustion of ethylene

Developing oxygen vacancies in the structural network of nanomaterials is one of the productive methods to improve catalytic performance. A novel low-cost ternary iron-manganese-copper mixed oxide catalyst, rich in oxygen vacancies, was successfully synthesized through co-precipitation and pyrolysis. It exhibited excellent catalytic oxidation efficiency. For the first time, the metal valence transformation, the synergy structure of absorption atoms, and the role of oxygen vacancies in the as-prepared Fe3Mn1Cu1Ox were examined using X-ray absorption near edge structure spectroscopy (XANES), extended X-ray absorption fine structure (EXAFS), and X-ray photoelectron spectroscopy (XPS) analyses. XANES/EXAFS characterization results unveil that pyrolysis temperature and metal doping effect induce the establishment of Fe3Mn1Cu1Ox mixed network associated with abundant fractures, which maintain amorphous particles with plenty of oxygen vacancies and lattice oxygen. The Fe3Mn1Cu1Ox mixed network catalyst attributed to the synergistic interaction of metal oxides matrix in generating Mn4+-O2--Fe3+-O2--Cu2+ entities and led to excellent catalytic oxidation performance. Results confirmed that the structure of Fe3Mn1Cu1Ox catalyst remained stable and active after oxidizing ethylene, depicting its super durability. Thus, a redox cycle of catalytic mechanism was proposed. This work provides new insights into constructing high-performance and stable catalysts with abundant oxygen vacancies of metal mixed oxides for VOCs elimination.