Details

Autor(en) / Beteiligte

• Hu, Hao
• Zhang, Peng
• Xiao, Bei-Bei
• Mi, Jian-Li

Titel

Substrate Strain Engineering of Single-Atomic Sn‑N4 Sites Embedded in Various Carbon Matrixes for Bifunctional Oxygen Electrocatalysis

Ist Teil von

• ACS applied materials & interfaces, 2023-05, Vol.15 (19), p.23170-23184

Ort / Verlag

American Chemical Society

Erscheinungsjahr

2023

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• It is still a great challenge to design and synthesize high-efficiency and low-cost single-atom catalysts (SACs) as promising bifunctional electrocatalysts for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Herein, theoretical insights into Sn-N4 embedded carbon nanotubes, graphene quantum dots, and graphene nanosheets (denoted as Sn-N4-CNTs, Sn-N4-GQDs, and Sn-N4-Gra, respectively) for the ORR/OER are systematically provided. These results show that the protruding Sn atom creates a Sn-N4 pyramid and induces varied strain transfer between Sn-N4 and different carbon substrates prior to adsorption of O intermediates, resulting in the opposite response of the adsorption strengths of O intermediates to the substrate curvature of Sn-N4-CNTs and Sn-N4-GQDs. The torsional strain induced by OH* and OOH* on the Sn atom of Sn-N4-CNTs breaks the scaling relations between the adsorption strengths of O intermediates. Consequently, Sn-N4-CNTs with suitable curvature achieve outstanding ORR performance with very low overpotentials (0.28 V). Furthermore, the increase of curvature boosts the OER activity of Sn-N4-CNTs. For Sn-N4-GQDs, high curvature contributes to promoted OER activity but reduced ORR activity. The electronic interactions reveal the electron transfer from the s/p-bands of Sn to the half-filled β states of the frontier orbitals of O intermediates.