Modulation of Electronic Synergy to Enhance the Intrinsic Activity of Fe5 Ni4 S8 Nanosheets in Restricted Space Carbonized Wood Frameworks for Efficient Oxygen Evolution Reaction

Small. 2023 Dec 14:e2308928. doi: 10.1002/smll.202308928. Online ahead of print.

Abstract

Modulation of electronic structure and composition is widely recognized as an effective strategy to improve electrocatalyst performance. Herein, using a simple simultaneous carbonization and sulfidation strategy, NiFe double hydroxide-derived Fe5 Ni4 S8 (FNS) nanosheets immobilized on S-doped carbonized wood (SCW) framework by taking benefit of the orientation-constrained cavity and hierarchical porous structure of wood is proposed. Benefiting from the synergistic relationships between bimetal ions, the spatial confinement offered by the wood cavity, and the enhanced structural effects of the nanosheets array, the FNS/SCW exhibit enhanced intrinsic activity, increased accessibility of catalytically active sites, and convection-facilitated mass transport, resulting in an excellent oxygen evolution reaction (OER) activity and durability. Specifically, it takes a low overpotential of 230 mV at 50 mA cm-2 and potential increase is negligible (3.8%) at 50 mA cm-2 for 80 hours. Density functional theory (DFT) calculations further reveal that the synergistic effect of bimetal can optimize the electronic structure and lower the reaction energy barrier. The FNS/SCW used as the cathode of zinc-air battery shows higher power density and excellent durability relative to commercial RuO2 , exhibiting a good application prospect. Overall, this research offers proposals for designing and producing effective OER electrocatalysts using sustainable resources.

Keywords: electrocatalyst; hierarchical porous structure; oxygen evolution reaction; synergistic effect; wood.