Nanoconfinement of Ultrafine Rh within RuO2-Modified Hollow Carbon Spheres for Efficient Methanol Electrooxidation

Direct methanol fuel cells have attracted extensive research interest, yet their practical advancement remains constrained by the inadequate activity and durability of conventional platinum-based anode catalysts. In response to these limitations, here we develop a non-platinum catalyst consisting of ultrafine rhodium nanocrystals confined within a ruthenium dioxide-modified hollow carbon sphere (Rh/RuO2−HCS) through a stepwise stereoconstruction approach. The hollow carbon sphere framework with plentiful mesoporous channels facilitates the transport of both electrons and ions, while RuO2 acts as a co-catalyst that supplies abundant hydroxyl species to oxidize CO intermediates, both of which are conducive to fully realizing the catalytic functions of Rh component. Benefiting from this synergistic design, the optimized Rh/RuO2−HCS catalyst exhibits outstanding methanol electrooxidation performance with large electrochemical surface area, high mass activity, and reliable durability, significantly superior to unmodified HCS and conventional carbon black-supported Rh catalysts.