Edge-substituents and center metal optimization boosting oxygen electrocatalysis in porphyrin-based covalent organic polymers

作者：Hongyan Zhuo, Qiming Ye, Shaoze Wang, Yu Han, Tianle Yang, Binghan Jiang, Chuangyu Wei, Linlin Feng, Tenglong Jin, Xue Liu, Zhuang Shi, Hao Song, Zhen Fu, Wenmiao Chen, Yuexing Zhang, Yanli Chen · 发表于：Journal of Colloid and Interface Science · 年份：2024 · DOI：10.1016/j.jcis.2024.11.109 · 被引用次数：17 · 研究领域：Electrocatalysts for Energy Conversion、Fuel Cells and Related Materials、Advanced battery technologies research

The promising non-noble electrocatalyst with well-defined structure is significant for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) for the renewable energy devices like zinc-air batteries (ZABs). Herein, the four phenyl-linked cobaltporphyrin-based covalent organic polymers (COPs-1–4) with the different edge substituents (1 = − t Bu, 2 = −Me, 3 = −F, and 4 = −CF 3 ) are firstly designed and synthesized via a simple, efficient one-pot method. With the increase of electron donating capacity of the substituents, the highest occupied molecular orbital energy ( E HOMO ) gradually increases in the order of COP-4 < COP-3 < COP-2 < COP-1. Consequently, the optimal COP-1 with − t Bu edge groups exhibits the highest half-wave potential ( E 1/2 ) of 0.84 V (vs. RHE) among the four COPs, which is comparable with commercial Pt/C in alkaline media. The DFT calculations further reveal that with strong electron donating capacity, the Gibbs free energy decreases in the order of COP-4 > COP-3 > COP-2 > COP-1 by modulating the adsorption energy of OOH* at rate-determining step (RDS) to promote ORR activity. Furthermore, introducing Ni (II) and Co (II) into porphyrin centers afford the bimetallic CoNi-COP-1 with both Co-N 4 , Ni-N 4 active sites and edge substituted − t Bu. The synergistic effect of Co, Ni bimetallic active sites and strong electron-donating − t Bu substituents renders the CoNi-COP-1 the highest HOMO and smallest energy gap between the E LUMO and E F...