The Cu─O─Co Asymmetric Bimetallic Sites Constructed by Ion‐Exchange for Efficient Oxygen Evolution Reaction
Congcong Liang, Haoqiang Ai, Lingtong Lin, Xingye Lu, L. Li, Honggang Zhang, Peng Wang, Zhaoke Zheng, Zeyan Wang, Hefeng Cheng, Ying Dai, Danning Xing, Baibiao Huang, Yuanyuan Liu
Abstract
Abstract Recently, constructing oxygen‐bridged asymmetric bimetallic sites has proven to be an effective strategy for enhancing electrocatalytic activity. The strong electronic interaction between the metals regulates the d‐band center, optimizing the adsorption and desorption of oxygen intermediates and lowering the oxygen evolution reaction (OER) energy barrier. However, examples of constructing such asymmetric sites in π‐d conductive metal‐organic frameworks (cMOFs) are still scarce. Here, the Co/Cu‐DBC (DBC = Dibenzo‐[g,p]chrysene‐2,3,6,7,10,11,14,15‐octaol) with high crystallinity and asymmetric Cu─O─Co bimetallic sites are prepared using an ion‐exchange method. By varying the reaction temperature and time, the metal content can be precisely controlled. The Co/Cu‐DBC shows excellent OER activity, with a small overpotential of 251 mV at 10 mA cm −2 . Both experimental and density functional theory (DFT) calculations indicate that the construction of asymmetric Cu─O─Co sites leads to strong electronic interactions between Cu and Co through the axial oxygen atom, which regulates the d‐band center energy (E d ) level and electronic structure to optimize the adsorption of intermediates and facilitate the formation of * O intermediates on the active Co sites toward fast OER kinetics. This work provides new insights for the synthesis and the design of efficient OER catalysts.