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

Pd-based\nalloys are among the most attractive catalysts for direct\nalcohol fuel cells. However, their widespread use is limited by the\nhigh cost of Pd and their susceptibility to deactivation by surface-adsorbed\nreaction intermediates, particularly CO. In this study, we engineered\nan ultrathin 2D PdCr metallene to minimize Pd usage and doped it with\nphosphorus to enhance its CO tolerance. The resulting P-PdCr metallene\ndemonstrated significantly higher activity, stability, and CO tolerance\nfor the electrooxidation of various alcohols compared to PdCr metallene\nand commercial Pd/C catalysts. Particularly, for the methanol oxidation\nreaction (MOR), the P-PdCr catalyst achieved a mass activity of 2.64\nA mg<sup>–1</sup><sub>Pd</sub> and a specific activity of 5.81\nmA cm<sup>–2</sup>, maintaining remarkable stability over a\nduration of 27 h. Density functional theory calculations revealed\nthat the enhanced performance is attributed to the incorporation of\nCr and P atoms into the Pd metallene structure. This incorporation\nsignificantly reduces the energy barriers of the potential-determining\nstep in the MOR process, mitigates CO adsorption on the catalyst surface,\nand accelerates the conversion of reaction intermediates. The strategic\ndoping of phosphorus into the metallene structure introduces a novel\napproach for developing Pd-based catalysts with enhanced CO tolerance\nin alcohol electrooxidation.