Core-shell Ru@Pd/SBA-15 catalysts with various atomic layer numbers of Pd were prepared by changing the Pd/Ru ratio and Pd coating temperature. The results of characterizations show that the compressive strain of Pd atoms and electron transfer from Ru to Pd result in a downward shift in the d-band center of core–shell catalysts. Density functional theory calculations further reveal that the reduced d-band center of Pd via strain and electronic effects weakens the adsorption ability of Pd. A roughly volcano-shaped correlation between the d-band center and 2-ethyl-anthraquinone (EAQ) hydrogenation activity is experimentally observed. The catalyst with Pd shell of 2 atomic layers provides medium adsorption strength for EAQ and hydrogenated product, thereby exhibiting the highest activity of 0.37 molH2·gMet−1·min−1, with a selectivity of 97.3%. This work provides a facile strategy for optimizing hydrogenation performance by modulating the strain and electron effects between the Ru core and Pd shell through regulating the number of shell layers.

中文翻译：

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通过调节 d 波段中心提高核壳结构 Ru@Pd/SBA-15 在 2-乙基-蒽醌加氢反应中的催化性能


通过改变 Pd/Ru 比和 Pd 包覆温度，制备了具有不同原子层数 Pd 的核壳 Ru@Pd/SBA-15 催化剂。表征结果表明，Pd 原子的压缩应变和从 Ru 到 Pd 的电子转移导致核壳催化剂的 d 带中心向下移动。密度泛函理论计算进一步表明，应变和电子效应导致 Pd 的 d 波段中心减小，削弱了 Pd 的吸附能力。实验观察到 d 波段中心和 2-乙基-蒽醌 （EAQ） 氢化活性之间大致呈火山状的相关性。具有 2 个原子层 Pd 壳层的催化剂为 EAQ 和氢化产物提供了中等吸附强度，因此表现出 0.37 molH2·gMet−1·min-1 的最高活性，选择性为 97.3%。这项工作通过调节壳层数来调节 Ru 核和 Pd 壳层之间的应变和电子效应，为优化氢化性能提供了一种简单的策略。