National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, Hefei, Anhui, 230029, China.
Hefei National Laboratory for Physical Sciences at the Microscale, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui, 230026, China.
Adv Mater. 2019 Feb;31(8):e1805127. doi: 10.1002/adma.201805127. Epub 2019 Jan 11.
Unravelling the intrinsic mechanism of electrocatalytic oxygen evolution reaction (OER) by use of heterogeneous catalysts is highly desirable to develop related energy conversion technologies. Albeit dynamic self-reconstruction of the catalysts during OER is extensively observed, it is still highly challenging to operando probe the reconstruction and precisely identify the true catalytically active components. Here, a new class of OER precatalyst, cobalt oxychloride (Co (OH) Cl) with unique features that allow a gradual phase reconstruction during OER due to the etching of lattice anion is demonstrated. The reconstruction continuously boosts OER activities. The reconstruction-derived component delivers remarkable performance in both alkaline and neutral electrolytes. Operando synchrotron radiation-based X-ray spectroscopic characterization together with density functional theory calculations discloses that the etching of lattice Cl serves as the key to trigger the reconstruction and the boosted catalytic performance roots in the atomic-level coordinatively unsaturated sites (CUS). This work establishes fundamental understanding on the OER mechanism associated with self-reconstruction of heterogeneous catalysts.
通过使用多相催化剂来揭示电催化氧气析出反应 (OER) 的内在机制，对于开发相关的能量转换技术是非常可取的。尽管在 OER 过程中催化剂的动态自重建得到了广泛的观察，但在原位探测重建并精确识别真正的催化活性组分仍然具有很大的挑战性。在这里，展示了一类新型的 OER 前催化剂，即具有独特性质的氧氯化钴 (Co(OH)Cl)，由于晶格阴离子的蚀刻，它在 OER 过程中可以逐渐进行相重建。这种重建不断促进 OER 活性。重建衍生的成分在碱性和中性电解质中都表现出了显著的性能。基于同步辐射的原位 X 射线光谱学表征以及密度泛函理论计算揭示了晶格 Cl 的蚀刻是触发重建的关键，而增强的催化性能则源于原子级配位不饱和位点 (CUS)。这项工作为与多相催化剂自重建相关的 OER 机制提供了基本的认识。
