Ru/CeO2 catalyst derived from Ce-based MOF for highly efficient catalytic CO2 methanation integrated with renewable hydrogen

Abstract

A series of highly ordered microporous Ce-based metal-organic frameworks (MOFs) were synthesized as the precursors for catalyst construction. The corresponding Ru catalysts were prepared by Ru impregnation on the derived CeO2 by pyrolysis of Ce-MOF, and investigated for the CH4 synthesis via CO2 hydrogenation. Among the catalysts, Ru catalyst supported on the CeO2-B derived from Ce-BDC exhibited a highly competitive efficiency for CO2 methanation, giving a CH4 selectivity of 100% with a CO2 conversion of 62% at 275 °C and 0.1 MPa, and the CH4 productivity reached 0.49 mol/(molRu·h). Characterization results revealed that more oxygen vacancies and corresponding surface oxygen species formed on the surface of CeO2-B derived from Ce-BDC caused to the stronger interaction between Ru and CeO2-B, which promoted the CO2 adsorption and hydrogenation capacity of the catalyst, resulting in its better catalytic property. In situ diffuse reflectance infrared Fourier transform (DRIFT) studies further revealed that the route of HCOO* into CH4 is a more competitive way of CO2 hydrogenation to CH4.