Abstract：
The strong ligand effect in B-doped Pd-based (PdB) catalysts renders them a promising anode for constructing formic acid fuel cells (FAFCs) exhibiting high power density and outstanding stability. However, the enhancement of the oxidation barrier is unavoidable in this alloy system owing to the electron transfer (ET) from B to Pd. In this study, a hydrogen doping strategy is employed to open charge freedom in PdB compounds and boost their formic acid oxidation reaction (FAOR) activity by suppressing the ET process. The resulting hydrogen-doped PdB (PdBH) exhibits an ultrahigh mass activity of up to 1.2A mg-1 Pd, which is 3.23 times that of the PdB catalyst and 9.55 times that of Pd black. Detailed experimental and theoretical studies show that the interstitial hydrogen leads to enhanced orbital hybridization and reduced electron density around Pd. This optimized ligand effect weakens the carbon monoxide adsorption and increases the direct pathway preference of PdBH, resulting in its outstanding catalytic activity for the FAOR. The development of this high-performance hydrogen-doped PdB catalyst is an important step toward the construction of advanced light element co-doped metal catalysts.
摘要：
B掺杂的Pd基（PdB）催化剂中的强配体效应使其成为构建具有高功率密度和出色稳定性的甲酸燃料电池（FAFCs）的有希望的阳极。然而,由于从B到Pd的电子转移（ET），在该合金体系中氧化势垒的增强是不可避免的。在这项研究中,采用氢掺杂策略来打开PdB化合物中的电荷自由度，并通过抑制ET过程来提高其甲酸氧化反应（FAOR）活性。所得的氢掺杂PdB（PdBH）具有高达1.2Amg-1Pd的超高质量活性，是PdB催化剂的3.23倍和Pd黑的9.55倍。详细的实验和理论研究表明，间隙氢导致Pd周围的轨道杂化增强和电子密度降低。这种优化的配体效应削弱了一氧化碳的吸附并增加了PdBH的直接途径偏好，导致其对FAOR的出色催化活性。这种高性能氢掺杂PdB催化剂的开发是朝着构建先进的轻元素共掺杂金属催化剂迈出的重要一步。
