Highly Dispersed Molybdenum Oxycarbide Clusters Supported on Multilayer Graphene for the Selective Reduction of Carbon Dioxide

Abstract Molybdenum oxycarbide clusters are novel nanomaterials that exhibit attractive catalytic activity; however, the methods for their production are currently very restrictive. This work represents a new strategy for the creation of near‐subnanometer size molybdenum oxycarbide clusters on multilayer graphene. To adsorb Mo‐based polyoxometalates of the type [PMo₁₂O₄₀]³⁻ as a precursor for Mo oxycarbide clusters, the novel tripodal‐phenyl cation N,N,N‐tri(4‐phenylbutyl)‐N‐methylammonium ([TPBMA]⁺) is synthesized. [TPBMA]⁺ exhibits superior adsorption on multilayer graphene compared to commercially available cations such as tetrabutylammonium ([nBu₄N]⁺) and tetraphenylphosphonium ([PPh₄]⁺). Using [TPBMA]⁺ as an anchor, highly dispersed precursor clusters (diameter: 1.0 ± 0.2 nm) supported on multilayer graphene are obtained, as confirmed by high‐resolution scanning transmission electron microscopy. Remarkably, this new material achieves the catalytic reduction of CO₂ to selectively produce CO (≈99.9%) via the reverse water‐gas‐shift reaction, by applying carbothermal hydrogen reduction to generate Mo oxycarbide clusters in situ.