Modulating the electronic structure and O-intermediates' chemisorption behavior of Pd metallene with boosted oxygen reduction reaction (ORR) performance is critical to advance proton exchange membrane fuel cells (PEMFCs). Herein, Hf doping Pd metallene (Hf-Pd metallene) is developed for efficient ORR electrocatalysis. Multiple characterizations and theoretical simulations disclose that the Hf dopant located in the inner atomic layers of Hf-Pd metallene could modulate the electronic configuration of Pd, lower the binding energies of the Pd d-band centers toward O-related intermediates, deliver a much reduced overpotential during O* hydrogenation into OH*, and thus enhance the catalytic activity. Consequently, the Hf-Pd metallene delivers superior ORR electrocatalytic activity together with excellent stability, surpassing commercial Pt/C and various advanced Pd-based catalysts. Encouragingly, when utilized as the cathode in a PEMFC, the Hf-Pd metallene achieved the higher maximum power density (722.75 mW cm−2) as compared to Pt/C-based batteries, elucidating the practical application of Hf-Pd metallene in PEMFCs.

中文翻译：

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通过阳离子掺杂优化 O 中间体对金属钯的化学吸附行为，可在 PEMFC 中实现高效的氧还原


通过提高氧还原反应 （ORR） 性能来调节 Pd 金属烯的电子结构和 O 中间体的化学吸附行为，对于推进质子交换膜燃料电池 （PEMFC） 至关重要。在此，Hf 掺杂金属钯 （Hf-Pd metallene） 是为高效的 ORR 电催化而开发的。多重表征和理论模拟表明，位于 Hf-Pd 金属内原子层的 Hf 掺杂剂可以调节 Pd 的电子构型，降低 Pd d 波段中心对 O 相关中间体的结合能，在 O* 氢化成 OH* 过程中提供大大降低的过电位，从而提高催化活性。因此，Hf-Pd 金属烯具有卓越的 ORR 电催化活性和出色的稳定性，超越了市售 Pt/C 和各种先进的 Pd 基催化剂。令人鼓舞的是，当用作 PEMFC 中的阴极时，与 Pt/C 基电池相比，Hf-Pd 金属金属实现了更高的最大功率密度 （722.75 mW cm-2），阐明了 Hf-Pd 金属金属在 PEMFC 中的实际应用。