Catalytic performance of MoO3/FAU zeolite catalysts modified by Cu for reverse water gas shift reaction

The reverse water gas shift (rWGS) reaction using a supported zeolite catalyst containing molybdenum (Mo) was investigated. The Mo-based catalyst is expected to be effective for selective conversion of CO2 into CO. The focus of this work was on the performance of the Mo-based catalyst and the effect of adding copper (Cu) to the catalyst. The Mo catalyst exhibited high CO selectivity (99 %) with CO2 conversion of 14.3 % at 773 K. The activity of the catalyst containing Cu as an additive depended on the Mo/Cu ratio. For a series of Mo(x)Cu(1-x)/Faujasite (FAU) catalysts (x: metal content, mmol/g), the Mo(0.8)Cu(0.2)/FAU catalyst exhibited the best performance. X-ray diffraction, X-ray photoelectron spectroscopy and temperature-programmed reduction with hydrogen analysis of the Mo(x)Cu(1-x)/FAU catalysts revealed that the presence of Cu as an additive influenced the reduction step of MoO3 to MoO2, with MoO3 being the active species. Transmission electron microscopy verified morphology of MoO3 and Cu particles on the support. The excellent performance of the prepared Mo(0.8)Cu(0.2)/FAU catalyst was due to facilitation of the reduction process involving the Mo species.