RESUMEN
Multinary metal sulfides (MMSs) are highly suitable candidates for the application of electrocatalysis as they offer numerous parameters for optimizing the electronic structure and catalytic sites. Herein, a stable nanoarchitecture consisting of MMSs ((NiCoCrMnFe)Sx) nanoparticles embedded in S, N-codoped carbon (SNC) layers derived from metal organic framework (MOF) and supported on carbonized wood fibers (CWF) was fabricated by directly carbonization. Benefiting from this carbon-coated configuration, along with the synergistic effects within multinary metal systems, (NiCoCrMnFe)Sx@SNC/CWF delivers an exceptionally low overpotential of 260 mV at a high current density of 1000 mA cm-2, a small Tafel slope of 48.5 mV dec-1, and robust electrocatalytic stability. Furthermore, the (NiCoCrMnFe)Sx@SNC/CWF used as the cathode of rechargeable Zn-air batteries demonstrates higher power density and remarkable durability, surpassing that of commercial RuO2. Thus, we showcase the feasibility and advantages of employing highly efficient and durable MMSs materials for low-cost and sustainable energy conversion.
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
Bimetallic phosphides exhibit superior electrocatalytic activities and synergistic effects that make them ideal electrocatalysts for the urea oxidation reaction (UOR). Herein, P, N-codoped carbon-encapsulated cobalt/nickel phosphides derived from NiCo-MOF-74 (NiCoP@PNC) and anchored on P-doped carbonized wood fiber (PCWF) for UOR were prepared through synchronous carbonization and phosphorization. By benefiting from the synergistic effect of structural and electronic modulation, NiCoP@PNC/PCWF exhibits excellent UOR electrocatalytic performance under alkaline conditions, achieving a current density of 50 mA cm-2 with a potential of only 1.34 V (vs reversible hydrogen electrode, RHE) and continuous operation for more than 72 h. In addition, for the overall urea splitting, an electrolyzer using UOR replaced OER, which required only 1.50 V to achieve a current density of 50 mA cm-2 with excellent stability, 230 mV less than that required for the HER||OER system. In-depth theoretical analysis further proves that the strong synergistic effect between Co and Ni optimizes electronic structures, yielding excellent UOR properties. The synergistic strategy of structural and electrical modulation provides broad prospects for the design and synthesis of excellent UOR electrocatalysts for energy-saving hydrogen production by using renewable resources.