Preparation and electrochemical characterization of a new NiMoO 4 catalyst for electrochemical O 2 evolution

Abstract

The NiMoO 4 catalyst has been obtained by a precipitation method under a controlled pH condition and characterized ex situ by infrared, X-ray diffraction, Brunauer-Emmett-Teller (BET), and particle size, and in situ by cyclic voltammetry, impedance and steady-state anodic Tafel polarization techniques. Results show that NiMoO 4 has pure crystalline monoclinic phase with the crystallite size ~50 nm and the lattice constants, a∈=∈9.597 Å, b∈=∈8.765 Å, c∈=∈7.667 Å, and β∈=∈114.22°. Values of the average particle size and BET surface area of the oxide powders are found to be 730 nm and 11.75 m 2/g, respectively. The oxygen evolution reaction follows the first-order kinetics with respect to OH - concentration, the Tafel slope being ~70 mV. © 2008 Springer-Verlag.