Exploitation of MOF Decomposition Mechanisms to Tailor the MOF-Derived Carbon Structure in Mono- and Multimetallic PCN-250

Metal–organic framework (MOF)-templated materials, such as MOF-derived carbons (MOFdCs), are attractive materials for applications such as electrocatalysis and energy storage. Unfortunately, the black-box nature of their synthesis remains a barrier to their implementation, as it is difficult to target specific structural features or properties in the final material. In this work, we use the well-established decomposition mechanism of the iron-MOF PCN-250 to design a two-step MOF calcination procedure that selectively generates two features that cannot be simultaneously obtained in a single-step calcination, namely, high porosity and a single iron(II,II) oxide phase. The resulting MOFdC exhibits the highest porosity reported in a PCN-250-derived carbon to date (>300 m²/g), and iron(II,III) oxide is the only metal phase present. We further apply this procedure to bimetallic PCN-250 to form mixed-metal oxides with an iron(II,III) oxide-type structure in a highly porous carbon matrix. Calcination of cobalt- and manganese-doped PCN-250 using the two-step procedure successfully produced porous carbons containing a single metal oxide phase; however, calcination of nickel-doped PCN-250 produced a mixture of metal species and a carbon matrix with low porosity due to the increased resistance of the iron–nickel alloy intermediate to oxidation.

Calcination of cobalt- and manganese-doped PCN-250 using the two-step procedure successfully produced porous carbons containing a single metal oxide phase; however, calcination of nickel-doped PCN-250 produced a mixture of metal species and a carbon matrix with low porosity due to the increased resistance of the iron−nickel alloy intermediate to oxidation.