Atomic-level correlation between the electrochemical performance of an oxygen-evolving catalyst and the effects of CeO2 functionalization
Yanyan Li, Wen Luo, Duojie Wu, Qi Wang, Jie Yin, Pinxian Xi, Yongquan Qu, Meng Gu, Xinyu Zhang, Zhouguang Lu, Zhiping Zheng
Abstract
Herein, we prepared a bimetallic layered double hydroxide (FeCo LDH) featuring a dandelion-like structure. Anchoring of CeO 2 onto FeCo LDH produced interfaces between the functionalizing CeO 2 and the parent LDH. Comparative electrochemical studies were carried out. Onset potential, overpotential, and Tafel slope point to the superior oxygen-evolving performance of CeO 2 -FeCo LDH with respect to FeCo LDH, therefore, demonstrating the merits of CeO 2 functionalization. The electronic structures of Fe, Co, and Ce were analyzed by X-ray photoelectron spectroscopy (XPS) and electron energy loss spectroscopy (EELS) from which the increase of Co 3+ and the concurrent lowering of Ce 4+ were established. With the use of CeO 2 -FeCo LDH, accelerated formation at a sizably reduced potential of Co-OOH, one of the key intermediates preceding the release of O 2 was observed by in situ Raman spectroscopy. We now have the atomic-level and location-specific evidence, the increase of the active Co 3+ across the interface to correlate the enhanced catalytic performance with CeO 2 functionalization.