Operando assessment of electronic properties near the Fermi level is essential to gain new insights into the mechanisms of electrochemical reactions as well as for the development of more efficient electrocatalysts. However, the high vacuum ambient needed for X-ray absorption measurements at low energies has made studies under electrochemical conditions quite challenging. Here, we describe an out-of-chamber setup with a new electrochemical cell that allowed us to performed operando X-ray absorption studies at the low energy of the Pd L3 edge. Using the new electrochemical cell, we were able to probe, for the first time, the changes in electronic properties of carbon-supported Pd nanoparticles induced by the electrochemical oxidation of the Pd surface. Our results demonstrate that the oxidation process produces an increase in the Pd 4d band vacancy, which indicates that charge is transferred from the metal to the adsorbed oxygenated species.

对费米能级附近的电子性质进行Operando评估对于获得对电化学反应机理的新见解以及开发更有效的电催化剂至关重要。然而，在低能量下进行X射线吸收测量所需的高真空环境使得在电化学条件下的研究颇具挑战性。在这里，我们描述了一个带有新电化学电池的室外设备，该设备使我们能够在Pd L3边缘的低能量下进行操作X射线吸收研究。使用新的电化学电池，我们首次能够探测到由Pd表面的电化学氧化引起的碳载Pd纳米粒子的电子性能变化。我们的结果表明，氧化过程会增加Pd 4d带空位，