Preparation and electrochemical characterization of a new NiMoO4 catalyst for electrochemical O2 evolution

The NiMoO₄ 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 NiMoO₄ 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 m²/g, respectively. The oxygen evolution reaction follows the first-order kinetics with respect to OH^? concentration, the Tafel slope being ~70 mV.