Trace Iridium As ''Adhesive'' In Ptcuir Aerogels For Robust Methanol Electrooxidation

PtCu-based alloy nanomaterials have shown great potential in methanol oxidation reaction (MOR) owing to the lower cost and good anti-poisoning ability. However, the dissolution of non-precious metal makes them suffer from severe stability issues, greatly impeding the practical application of direct methanol fuel cells. Herein, PtCuIr aerogels are successfully fabricated through a one-step NaBH4 reduction strategy to anchor trace Ir on PtCu aerogels based on compositional engineering, which serves as advanced electrocatalysts to achieve enhanced electrocatalytic performance toward MOR. Particularly, the optimized PtCuIr aerogels show extraordinary stability and the mass activity maintains 71.2% of the initial value after 20,000 s chronoamperometric measurements. Density functional theory calculations certify that the doping of trace Ir considerably lowers the adsorption energy of CO-containing substances and thus enhances the MOR activity. By employing the vacancy formation energy of the surface Pt as the descriptor, it is revealed that the robust stability of PtCuIr aerogels originates mainly from the stronger bond between Ir and Pt/Cu atoms, where Ir acts as an.adhesive. to prevent the dissolution and leaching of atoms. The breakthrough of the highly stable MOR catalyst could open an avenue for affordable and durable fuel cells.