Oxygen vacancy mediated CuyCo3-yFe1Ox mixed oxide as highly active and stable toluene oxidation catalyst by multiple phase interfaces formation and metal doping effect

Abstract

For the transition metal oxide based VOCs oxidation catalysts, both the activity and thermal stability have to be further improved. In this work, we report the synthesis of oxygen vacancy mediated CuyCo3-yFe1Ox mixed oxide from LDH precursors as highly active and stable toluene oxidation catalyst. The effects of calcination temperature and molar ratio of Cu/Co on the redox, catalytic, texture and structural properties were investigated systematically. The obtained Cu1Co2Fe1Ox catalyst possessed a complete toluene conversion at 241 °C, which was much lower than that of Co3Fe1Ox (289 °C) and Cu3Fe1Ox (304 °C) catalysts. HR-TEM and DFT calculations confirmed that Cu1Co2Fe1Ox possesses abundant multi-phase interfaces and metal doping effect, which can induce the rich oxygen vacancies on the surface of catalysts. XPS, Raman and ESR analyses demonstrated that Cu1Co2Fe1Ox has much more oxygen vacancies than all other control catalysts. Kinetic studies indicated that Cu1Co2Fe1Ox catalyst possesses the lowest Ea value. In addition, Cu1Co2Fe1Ox catalyst also exhibited excellent durability during 30 h and good H2O resistance to 5% water steam. Thanks for the high activity and stability, fast reaction kinetics and H2O resistance, Cu1Co2Fe1Ox catalyst has shown great potential for practical applications.