Mutual Self-Regulation of d-Electrons of Single Atoms and Adjacent Nanoparticles for Bifunctional Oxygen Electrocatalysis and Rechargeable Zinc-Air Batteries

• DOI: 10.1007/s40820-023-01022-8
• Publication Date: 2023-02-11T12:11:39Z
• Authors: Sundaram Chandras...; Rong Hu; Lei Yao; Lijun Sui; Yongping Liu; Amor Abdelkader; Yongliang Li; Xiangzhong Ren; Libo Deng
• Keywords: Overpotential; Oxygen evolution

Rechargeable zinc-air batteries (ZABs) are a promising energy conversion device, which rely critically on electrocatalysts to accelerate their rate-determining reactions such as oxygen reduction (ORR) and evolution (OER). Herein, we fabricate range of bifunctional M-N-C (metal-nitrogen-carbon) catalysts containing M-Nx coordination sites M/MxC nanoparticles (M = Co, Fe, Cu) using new class γ-cyclodextrin (CD) based metal-organic framework the precursor. With two types active interacting with each other in catalysts, obtained Fe@C-FeNC Co@C-CoNC display superior alkaline ORR activity terms low half-wave (E1/2) potential (~ 0.917 0.906 V, respectively), higher than Cu@C-CuNC 0.829 V) commercial Pt/C 0.861 V). As electrocatalyst, exhibits best performance, showing ORR/OER overpotential (ΔE) ~ 0.732 is much lower that 0.831 1.411 V), well most robust reported date. Synchrotron X-ray absorption spectroscopy density functional theory simulations reveal strong electronic correlation between metallic Co atomic Co-N4 catalyst can increase d-electron near Fermi level thus effectively optimize adsorption/desorption intermediates ORR/OER, resulting an enhanced electrocatalytic performance. The Co@C-CoNC-based rechargeable ZAB exhibited maximum power 162.80 mW cm-2 at 270.30 mA cm-2, combination + RuO2 158.90 265.80 cm-2) catalysts. During galvanostatic discharge 10 delivered almost stable voltage 1.2 V for 140 h, signifying virtue excellent activity.