Macro- and Mesoporous Graphene-MXene Architectures Decorated with Rhodium Nanocrystals for Methanol Oxidation...

The development of advanced platinum-alternative anode catalysts with high catalytic activity and strong CO poison tolerance is of great significance to break through the technical bottleneck of the direct methanol fuel cell. Herein, we report the spatial construction of a rhodium-decorated three-dimensional macro- and mesoporous architecture built from holey graphene and holey Ti₃C₂T_x MXene (Rh/HG-HMX) through a combined oxidative-etching and solvothermal coassembly process. Such an exquisite structural design not only fully exposes the internal catalytically active sites as well as improves the mass transfer efficiency of reactants and products, but also affords strong interfacial interactions between metallic Rh and HG-HMX matrix to optimize their electronic structure, thus resulting in significant synergistic catalytic effects. Accordingly, the as-derived Rh/HG-HMX architecture exhibits excellent electrocatalytic methanol oxidation abilities in terms of a large electrochemically active surface area of 171.5 m²·g^-1, a high mass activity of 2082.0 mA·mg^-1, and dependable long-term durability, far exceeding those of traditional graphene and MXene-supported Rh catalysts as well as commercial Pt/C and Pd/C catalysts.