Integration of Phosphorus in PdCr Metallene for Enhanced CO-Tolerant Alcohol Electrooxidation

Pd-based alloys are among the most attractive catalysts for direct alcohol fuel cells. However, their widespread use is limited by the high cost of Pd and their susceptibility to deactivation by surface-adsorbed reaction intermediates, particularly CO. In this study, we engineered an ultrathin 2D PdCr metallene to minimize Pd usage and doped it with phosphorus to enhance its CO tolerance. The resulting P-PdCr metallene demonstrated significantly higher activity, stability, and CO tolerance for the electrooxidation of various alcohols compared to PdCr metallene and commercial Pd/C catalysts. Particularly, for the methanol oxidation reaction (MOR), the P-PdCr catalyst achieved a mass activity of 2.64 A mg^-1_Pd and a specific activity of 5.81 mA cm^-2, maintaining remarkable stability over a duration of 27 h. Density functional theory calculations revealed that the enhanced performance is attributed to the incorporation of Cr and P atoms into the Pd metallene structure. This incorporation significantly reduces the energy barriers of the potential-determining step in the MOR process, mitigates CO adsorption on the catalyst surface, and accelerates the conversion of reaction intermediates. The strategic doping of phosphorus into the metallene structure introduces a novel approach for developing Pd-based catalysts with enhanced CO tolerance in alcohol electrooxidation.