Synthesis of Layered Double Hydroxides and TiO2 Supported Metal Nanoparticles for Electrocatalysis

Abstract

AbstractIn the present work, solution‐phase synthesis was employed to prepare two sets of catalysts with different transition metals as active sites. One set contained Au or Pd supported on TiO2 (Au−TiO2, Pd−TiO2), whereas the other set contained layered double hydroxides (NiFe‐LDH and CuFe‐LDH). The electrocatalytic performance of these composite materials was investigated by cyclic voltammetry (CV) using a model compound 4‐nitrophenol (4‐NP). Composite materials were characterized by various analytical techniques to gain insight into the catalysts active sites. The morphology and structure of the prepared samples were investigated by X‐ray diffraction, attenuated total reflectance Fourier transform infrared, X‐ray photoelectron spectroscopy, transmission scanning electron microscope, and field emission scanning electron microscope. Metal nanoparticles loading on TiO2 was measured by inductively coupled plasma – optical emission spectrometry. CV measurements were performed in acetonitrile solution containing 0.1 m tetrabutylammonium hexafluorophosphate (TBAPF6) and 1 mm 4‐NP. Among all dioxides (Au−TiO2, Pd−TiO2) and hydroxides (NiFe‐LDH and CuFe‐LDH) studied, Pd−TiO2 shows the lowest onset potential (−0.32 V vs. Ag/AgCl) for the electrocatalytic reduction of 4‐NP. This is the first comparative study of such materials for 4‐NP electrocatalysis in aprotic solvent, thus demonstrating the suitability of dioxide and hydroxide based materials as electrocatalysts.