High-Density Cobalt Single-Atom Catalysts for Enhanced Oxygen Evolution Reaction
Pawan Kumar, Karthick Kannimuthu, Ali Shayesteh Zeraati, Soumyabrata Roy, Xiao Wang, Xiyang Wang, Subhajyoti Samanta, Kristen A. Miller, María Molina, Dhwanil Trivedi, Jehad Abed, M. Astrid Campos Mata, Hasan Al‐Mahayni, Jonas Baltrušaitis, George K. H. Shimizu, Yimin A. Wu, Ali Seifitokaldani, Edward H. Sargent, Pulickel M. Ajayan, Jinguang Hu, Md Golam Kibria
Abstract
Single atom catalysts (SACs) possess unique catalytic properties due to low-coordination and unsaturated active sites. However, the demonstrated performance of SACs is limited by low SAC loading, poor metal–support interactions, and nonstable performance. Herein, we report a macromolecule-assisted SAC synthesis approach that enabled us to demonstrate high-density Co single atoms (10.6 wt % Co SAC) in a pyridinic N-rich graphenic network. The highly porous carbon network (surface area of ∼186 m 2 g –1 ) with increased conjugation and vicinal Co site decoration in Co SACs significantly enhanced the electrocatalytic oxygen evolution reaction (OER) in 1 M KOH (η 10 at 351 mV; mass activity of 2209 mA mg Co –1 at 1.65 V) with more than 300 h stability. Operando X-ray absorption near-edge structure demonstrates the formation of electron-deficient Co-O coordination intermediates, accelerating OER kinetics. Density functional theory (DFT) calculations reveal the facile electron transfer from cobalt to oxygen species-accelerated OER.