Reversible Redox Transition and Pseudocapacitance of Molybdenum/Surface Molybdenum Oxides

Redox transitions and superior pseudocapacitance are two typical characteristics in the electrochemical behavior of metallic Mo (with surface Mo oxides) and bulk Mo oxides; both of which were attributed to the participation of H+/cations. The effects of different electrolyte anions (Cl-, SO42- and ClO4-) on redox transition and pseudocapacitance of thin-film 'Mo/Mo oxides' electrodes were assessed in this work through DC and AC electrochemical experiments. Voltammetric peak potentials and currents and potential-dependent pseudocapacitance were strongly dependent on the electrolyte's anion. The variations were tested at different electrolyte pH levels and using different electrolyte cations (Li+, Na+ and K+). The results were correlated with those obtained using a Se4+ based electrolyte. The findings reported here are expected to aid the applicability of Mo and its oxides in electrocatalysis, electrodeposition, supercapacitor, display, corrosion control and solar cells. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.047301jes] All rights reserved.