Atomic Cobalt-Doped Palladium Metallene toward Efficient Oxygen Reduction Electrocatalysis

Designing a high-efficiency catalyst for the cathode oxygen reduction reaction (ORR) in fuel cells still faces enormous challenges due to the stringent requirements for high power density and long-term durability. Palladium (Pd) metallene, on account of its unique properties and high Pd utilization efficiency, is recognized as a prospective candidate for enhancing the ORR catalytic performance. Herein, we present atomic cobalt (Co)-doped Pd metallene (Co-Pdene), featuring an ultrathin and highly curved morphology, developed via a straightforward wet-chemical approach for efficient ORR electrocatalysis in alkaline media. Resulting from the metallene structure and transition metal Co doping, the Co-Pdene catalyst demonstrates exceptional electrocatalytic performance, achieving an electrochemical mass activity (MA) of 3.14 A per milligram palladium at 0.85 V while maintaining structural integrity over 30000 potential cycles. Theory simulations (DFT) manifest that the single-atom Co sites optimize the electronic structure of palladium in the Co-Pdene, thereby lowering the theoretical overpotential to 0.29 V. This work proposes an innovative design strategy of single-atom transition metal-doped Pd metallene as a highly efficient ORR electrocatalyst.