RESUMEN
Herein, novel and efficient IF-supported NiCu (NiCu/IF) and NiMn (NiMn/IF) electrocatalysts are successfully deposited on iron foam (IF) via electrolysis of spent cupronickel (SCN), with outstanding performance for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) in an alkaline solution, respectively. The physical and electrochemical characterization results demonstrate that the catalysts possess a large active surface area, remarkable performance, and excellent durability.
RESUMEN
As a non-noble metal electrocatalyst for the oxygen evolution reaction (OER), the binary NiFe layer double hydroxide (LDH) is expected to replace Ru-based and Ir-based anode materials for water decomposition. To attain threshold current density, nevertheless, a somewhat significant overpotential is still needed. In this work, layered double hydroxides of NiFe LDH are doped with V to form the terpolymer NiFeV LDH, which greatly increases the intrinsic activity of NiFe LDH and improves OER performance. This process is a straightforward and quick one-step electrodeposition process. Notably, NiFeV/NF has a low overpotential (218 mV at 10 mA cm-2) and faster kinetics (Tafel slope of 31 mV dec-1) as well as excellent durability and stability in 1 M KOH solution. In addition, the OER performance of the catalyst prepared in this work is better than that of a non-valuable metal catalyst that was recently reported. The V-doped NiFe LDH layered double hydroxides and the investigation of electrodeposition electrocatalytic methods in this work offer a fresh opportunity for the advancement of electrochemical technology.
RESUMEN
In addition to complex preparation and low-yield syntheses, attaining high energy density while maintaining high power density remains a significant challenge for supercapacitor applications in the field of energy storage. Herein, two-dimensional (2D) nickel-based metal-organic framework (NiMOF) nanosheets are grown around carbon nanotubes (CNTs) to form NiMOF/CNTs composite, which is synthesized via a one-step solvothermal method at various temperatures. Thereinto, the NiMOF/CNTs composite synthesized at 180 °C (NiMOF/CNTs 180) exhibits enhanced electrical conductivity for ion and electron transport due to the addition of the CNTs, as well as the highest specific capacitance due to the unique 3D vine-like structure, which provides abundant active sites for electrochemical reactions. Specifically, the NiMOF/CNTs 180 composite demonstrates outstanding electrochemical performance with high specific capacitance (1855.0 F g-1 at 1 A g-1) and an excellent capacitance retention of 87.7% at 10 A g-1, indicating a favorable rate performance. The NiMOF/CNTs 180//AC asymmetric supercapacitors (ASCs) device assembled with NiMOF/CNTs 180 and activated carbon (AC) has a high specific capacitance of 320.0 F g-1 at 1 A g-1 and a maximum energy density of 113.8 W h kg-1 at 800.0 W kg-1. Therefore, the present work provides a handy and efficient synthesis strategy for supercapacitor devices with high energy density.