Direct formic acid fuel cells (DFAFCs) are considered promising sustainable power sources due to their high energy density, nonflammability, and low fuel crossover. However, serious CO poisoning and activity attenuation of the anodic formic acid oxidation reaction (FAOR) greatly restrict the output and durability of DFAFCs. Inspired by the specific relationship between the composition, type, and property of alloys, in this work, we synthesize a series of hybrid substitutional/interstitial quaternary alloys P-PdAuAg by means of a novel polyphosphide route to address these issues. Due to the simultaneous interstitial P-doping and metal (Au, Ag, Pd) co-reduction, the P-PdAuAg quaternary alloy obtained is only 3 nm in diameter with abundant defects. It not only achieves a new high mass activity of 8.08 A mg_Pd^–1 (6.78 A mg_catalyst^–1) but also maintains high stability in the high potential range and harsh reaction conditions. Both the activity and anti-poisoning ability are far exceeding those of the currently reported FAOR catalysts. Detailed density functional theory (DFT) calculations reveal that the superb electrochemical performances originate from the shift of the d-band center of Pd as a result of the synergistic electronic/ligand effects between Pd, Au, Ag, and P. The introduction of interstitial P inhibits the occurrence of an indirect reaction pathway on Pd, while Au and Ag suppress the adsorption of CO and optimize the sequential dehydrogenation steps, leading to boosted reaction kinetics and CO tolerance. This work pioneered a facile way for the synthesis of Pd-based substitutional/interstitial hybrid alloys, providing a promising means of further improving the performance of alloying catalysts.

中文翻译：

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通过 P-PdAuAg 四元合金提高电催化甲酸氧化活性

直接甲酸燃料电池 (DFAFC) 被认为是有前途的可持续能源，因为它们具有高能量密度、不可燃性和低燃料交叉。然而，严重的CO中毒和阳极甲酸氧化反应（FAOR）的活性衰减极大地限制了DFAFCs的产量和耐久性。受合金的成分、类型和性能之间的特定关系的启发，在这项工作中，我们通过一种新的多磷化途径合成了一系列混合替代/间隙四元合金 P-PdAuAg 来解决这些问题。由于同时间隙P掺杂和金属（Au、Ag、Pd）共还原，所获得的P-PdAuAg四元合金直径仅为3 nm，缺陷丰富。_{它不仅实现了 8.08 A mg Pd} ^–1的新高质量活性(6.78 A 毫克_催化剂^–1)，而且在高电位范围和苛刻的反应条件下也能保持高稳定性。无论是活性还是抗中毒能力都远超目前报道的FAOR催化剂。详细的密度泛函理论 (DFT) 计算表明，由于 Pd、Au、Ag 和 P 之间的协同电子/配体效应，Pd 的 d 带中心发生了偏移，从而产生了出色的电化学性能。 P 抑制 Pd 上间接反应途径的发生，而 Au 和 Ag 抑制 CO 的吸附并优化顺序脱氢步骤，从而提高反应动力学和 CO 耐受性。这项工作开创了一种合成 Pd 基替代/间隙杂化合金的简便方法，