While the primary role of supports in catalysis has been to anchor metal particles to prevent sintering, supports can also activate catalytic processes. We report computational and experimental results that provide a fundamental understanding of how a graphene support may activate both oxidative and reductive reaction steps in the catalytic cycle of Suzuki-Miyaura palladium-catalyzed cross-coupling reactions. Theoretical investigations reveal that the high catalytic activity is linked to the ability of a graphene support to act as both an efficient charge donor and acceptor in oxidation and reduction reaction steps. We compare the activation energy and turn over frequency for a series of supported and homogeneous catalysts and find that exposing palladium-graphene to defect inducing microwave radiation results in dramatically lower activation energies and higher turnover frequencies. These results explain why a defected graphene support may catalyze reaction steps that require both charge donation, and charge acceptance.

尽管载体在催化中的主要作用是固定金属颗粒以防止烧结，但载体也可以激活催化过程。我们报告了计算和实验结果，这些结果提供了对石墨烯载体如何激活Suzuki-Miyaura钯催化的交叉偶联反应的催化循环中的氧化和还原反应步骤的基本了解。理论研究表明，高催化活性与石墨烯载体在氧化和还原反应步骤中同时充当有效电荷供体和受体的能力有关。我们比较了一系列负载型催化剂和均相催化剂的活化能和转换频率，发现将钯-石墨烯暴露于缺陷诱导微波辐射会大大降低活化能和提高转换频率。这些结果解释了为什么有缺陷的石墨烯载体可能催化需要电荷捐赠和电荷接受的反应步骤。