Carbonized Nickel-Incorporated Metal-Organic Frameworks for Methane Reforming: Post-Synthetic Modification vs Impregnation

Nickel is one of the most attractive catalytically activespeciesfor methane reforming-a crucial process for producing liquidfuels and methanol, and the use of nanoporous materials to supportnickel is usually necessary. Impregnation is the commonly used methodto incorporate nickel into a porous support. In this work, we incorporatecatalytically active nickel into a highly porous cerium(IV)-basedmetal-organic framework (MOF) by utilizing either the conventionalimpregnation or the self-limiting post-synthetic modification, andthe nanosized MOF-derived ceria-supported nickel is prepared by carbonizingthe nickel-incorporated Ce-based MOFs. The crystallinity, porosity,nanostructural morphology, and surface properties of each MOF andMOF-derived materials are characterized, and as a demonstration, theMOF-derived catalysts are used for the bi-reforming of methane (BRM).The catalytic activity at various temperatures is examined, and thelong-term stability of MOF-derived catalysts for BRM is investigatedat 600 degrees C. The presence of MOF-derived carbon is necessary toinitiate the BRM at a lower temperature, and compared to the conventionalimpregnation, the use of post-synthetic modification to install thespatially separated nickel sites in the parent MOF can effectivelyretard the agglomeration of nickel in the final MOF-derived catalystduring the long-term BRM. Findings here suggest that the use of post-syntheticmodification to install the catalytically active species in MOFs isbeneficial for designing the MOF-derived catalysts that are more resistiveto sintering.