Hydride-forming metal nanoparticles sustaining localized surface plasmon resonance have emerged as prototypical material to study the fundamentals of hydrogen-induced phase transformations. They have also been proposed as signal transducers in next-generation hydrogen sensors. However, despite high current interest in hydrogen sorption by nanomaterials in general and such sensors in particular, the correlations between nanoparticle size, shape, and composition, the amount of hydrogen absorbed, and the obtained optical response have not been systematically experimentally studied. Focusing on hydrogenated Pd, PdAu- and PdCu-alloy nanoparticles, which are of particular interest in hysteresis-free plasmonic hydrogen sensing, we find that at practically important Au/Pd and Cu/Pd ratios the optical response to hydrogen concentration is linear and, more interestingly, can be described by a single universal linear trend if constructed as a function of the H/Pd ratio, independent of alloy composition. In addition to this correlation, we establish that the amplitude of optical signal change is defined solely by the spectral plasmon resonance position in the non-hydrogenated state for a specific nanoparticle composition. Thus, it can be maximized by red-shifting the LSPR into the NIR spectral range via tailoring the particle size and shape. These findings further establish plasmonic sensing as an effective tool for studying metal–hydrogen interactions in nanoparticles of complex chemical composition. They also represent universal design rules for metal-hydride-based plasmonic hydrogen sensors, and our theoretical analysis predicts that they are applicable not only to the H/Pd/Au or H/Pd/Cu system investigated here but also to other H/Pd/Metal combinations.

中文翻译：

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Pd和Pd合金纳米粒子中氢致光学性质的通用尺度和设计规则

维持局部表面等离子体激元共振的形成氢化物的金属纳米粒子已成为研究氢诱导相变基本原理的典型材料。它们也已被提议作为下一代氢传感器中的信号传感器。然而，尽管目前普遍对纳米材料尤其是这种传感器对氢的吸收感兴趣，但是尚未系统地实验研究纳米颗粒尺寸，形状和组成，所吸收的氢的量以及所获得的光学响应之间的相关性。着眼于氢化的Pd，PdAu和PdCu合金纳米颗粒，这些颗粒在无磁滞等离子体氢感测中特别重要，我们发现在非常重要的Au / Pd和Cu / Pd比率下，对氢浓度的光学响应是线性的，并且 更有趣的是，如果将其构造为H / Pd比的函数，则可以由单个通用线性趋势来描述，而与合金成分无关。除了这种相关性之外，我们确定光信号变化的幅度仅由特定纳米粒子组成的非氢化状态下的光谱等离振子共振位置定义。因此，可以通过调整颗粒大小和形状将LSPR红移到NIR光谱范围内，从而将其最大化。这些发现进一步将等离激元传感确立为研究复杂化学组成的纳米粒子中金属与氢相互作用的有效工具。它们还代表了基于金属氢化物的等离子体氢传感器的通用设计规则，