Facile synthesis and novel electrocatalytic performance of nanostructured Ni–Al layered double hydroxide/carbon nanotube composites

Abstract

Nanostructured Ni–Al layered double hydroxide/carbon nanotube (LDH/CNT) composites, where LDH nanocrystallites could highly disperse on the surface of CNTs matrix through the interfacial electrostatic interaction between the positively-charged layers of LDH and the negatively-charged functional groups of modified CNTs, have been successfully synthesized by a simple one-pot coprecipitation method. The materials were characterized by powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), thermogravimetry and differential scanning calorimetry (TG-DSC), transmission electron microscopy (TEM), Raman spectra, UV-visible absorption spectra (UV-VIS) and X-ray photoelectron spectra (XPS). The results reveal that the surface coverage of LDH nanoparticles onto CNTs could be tuned easily by changing the mass ratios of CNTs to LDH. The strong electrostatic interaction between LDH and CNTs gave rise to both the weakened affinity between the layers and the interlayer species of LDH and the high positive shift of binding energy for metal and oxygen elements (around 1.8 eV) in LDH/CNT composites. Further, the electrode modified by LDH/CNT nanocomposites exhibits eight times higher electrocatalytic activity for glucose electrooxidation than those modified by either pristine LDH or CNTs, which is attributable to the cooperative effects of the unique hybrid nanostructure and the composition of the as-synthesized nanostructured LDH/CNT composites. The present work provides a simple and feasible approach for incorporating two types of functional CNT and LDH materials into nanocomposites, which can result in the enhanced performance to meet advanced applications.