High-Density Cobalt Single-Atom Catalysts for Enhanced Oxygen Evolution Reaction

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 m2 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 (η10 at 351 mV; mass activity of 2209 mA mgCo –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.

Atomically dispersed Ni activates adjacent Ce sites for enhanced electrocatalytic oxygen evolution activity

“…4C). The excellent OER activity and kinetics enable a-Ni/CeO 2 @NC to be one of the most promising noble metal-free SACs for OER in the alkaline medium (table S3) (37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52).…”

Tip effect assisted high active sites for oxygen evolution reaction tuned using transition metals (Cr, Fe and Mo) doped with CoP

“…The optimized d-band centre balanced the adsorption and desorption of the reaction intermediates for improved OER catalytic activity. 24 The 3D and 2D differential charge density diagrams of Cr-CoP, Fe-CoP, Mo-CoP, and CoP are shown in Fig. 3c and d.…”

2D layered materials: structures, synthesis, and electrocatalytic applications

“…Two types of G-SACs are prevalent: one is loaded with noble metals, including Pd, 142,143 Pt, 144–146 Au, and Ru. 147 The other is single atoms of non-precious metals, such as alkaline earth metals 148 and transition metals, including Fe, 149 Co, 150 Ni, 151,152 Cu, 153 and W 154 among others. Qiu et al used a template-assisted approach to anchor iron single atoms onto highly stable hollow graphene nanospheres, resulting in catalysts with exceptional ORR performance due to the combination of atomically dispersed Fe active centers and the stable substrate.…”