Heterobimetallic Iridium-Niobia Catalyst for Efficient and Selective Methane Ammonia Reforming

High Resolution Image Download MS PowerPoint Slide A Surface OrganoMetallic Chemistry (SOMC) approach, leveraging a molecularly defined heterobimetallic niobium–iridium complex, was used to prepare a mesoporous SBA-15 silica-supported Ir-NbO x catalyst. The resulting Ir-NbO x /SiO 2 catalyst exhibited excellent catalytic performance in selective methane/ammonia reforming. Specifically, the Ir-NbO x /SiO 2 catalyst showed significantly higher activity (turnover frequency 8.5 s –1 ), selectivity (75%), and stability than the Ir/SiO 2 analog, whereas the NbO x /SiO 2 counterpart was almost inactive. This contrasts with ethane/ammonia reforming via C–C cleavage, for which the bimetallic Ir-NbO x /SiO 2 was less active than Ir/SiO 2, demonstrating tuned selectivity toward C–H activation rather than C–C cleavage due to the Ir/NbO x synergy. Importantly, an Ir-NbO x /SiO 2 reference catalyst, prepared by conventional impregnation/calcination/reduction steps, was found to be inactive, highlighting the value of the SOMC catalyst preparation approach using well-defined heterobimetallic precursors. These results represent a significant advance over existing catalysts due to the atomic-scale synergy between Ir and NbO x sites, enabling access to activity and selectivity regimes inaccessible to monometallic analogs.