RESUMEN
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 Fe5Ni4S8 (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.
RESUMEN
Exploring highly efficient, robust, and stable catalysts for urea electrolysis is intensively desirable for hydrogen production but remains a challenging task. In this work, novel, well-aligned, self-supported NiS/Ni3S4 heteronanorod arrays deposited on graphitized carbonized wood (GCW) are designed (denoted as NiS/Ni3S4/GCW) and synthesized by a facile hydrothermal sulfidation strategy. Benefitting from the optimized surface hydrophilicity/aerophobicity, enhanced electrical conductivity, and 3D hierarchical directional porous architectures, the NiS/Ni3S4/GCW show excellent activity toward the urea oxidation reaction and hydrogen evolution reaction in alkaline electrolytes. The arrays achieved a low potential of 1.33 V (vs. RHE) and 91 mV (overpotential) at 10 mA cm-2 as well as robust stability for 100 h. Significantly, when employed as anode and cathode simultaneously, the urea electrolyzer constructed by NiS/Ni3S4/GCW catalysts merely requires a low voltage of 1.44 V to drive 10 mA cm-2 with superior stability for 50 h. This work not only demonstrates the application of heterogeneous sulfide for urea-assisted hydrogen production but also provides an effective guideline for using renewable wood for designing efficient catalysts in an economical way.
