Ultrasonic-assisted synthesis of Ni based-layered double hydroxide doped carbon nanotube and its highly efficient in water oxidation reaction

Abstract

Among the developed electrocatalysts, NiCr-layered double hydroxides (NiCr-LDH) are one of the most effective electrocatalytic materials for water oxidation. However, applications of such a kind of materials are practically limited due to their poor electric conductivity. In this work, the single-walled carbon nanotube (SWCNT) was doped to NiCr-LDH, and the LDH-based nanocomposites were synthesized using the one-step ultrasonic-assisted method. Physicochemical properties of the NiCr-LDH/SWCNT composites were characterized by means of X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), field emission−scanning electron microscopy (FE−SEM), and linear sweep voltammetry (LSV). The NiCr-LDH/SWCNT composites were used as effective nanomaterials for oxygen evolution reaction (OER) at a near neutral medium. The LSV results confirm that the overpotential of the NiCr-LDH/SWCNT-0.006 sample decreased to about 120 mV at pH = 9.5, as compared with that of the NiCr-LDH or NiCr-LDH-SWCNT-0.006 (prepared by the two-step method) sample. The high oxygen evolution activity of NiCr-LDH/SWCNT-0.006 was associated with the co-presence of the homogeneously dispersed NiCr-LDH, good electrochemical activity, and high electrical conductivity. In addition, the as-prepared optimized NiCr-LDH/SWCNT electrocatalyst was highly stable for the OER reaction.