title: Copper-iron-molybdenum mixed oxides as efficient oxygen evolution electrocatalysts.
abstract: Ternary Cu, Fe and Mo mixed oxides having a nominal compositional formula, CuxFe2-x(MoO4)3 (0 ≤ x ≤ 1.5), have been prepared by a co-precipitation method at pH ≈ 2 and characterized by FT-IR, XRD, XPS, TEM and anodic polarization techniques for use as electrocatalysts for the oxygen evolution reaction (OER) in alkaline solutions. The crystallites of oxides with x ≤ 1 have the monoclinic crystal structure. The OER study shows that replacement of Fe in the Fe2(MoO4)3 matrix by 0.25-1.0 mol Cu increases the apparent electrocatalytic activity. However, 1.5 mol Cu-addition is detrimental to the OER activity. At E = 1.51 V (vs. RHE) in 1 M KOH, the catalytic activity of the oxide with x = 1 was approximately 50 times the activity of the base oxide (i.e. Fe2(MoO4)3). The Tafel slope of oxides with 0.25 ≤ x ≤ 1.5 ranged between 31 and 37 mV. The reaction order of OH(-) concentration was nearly unity for oxides with x = 0.25 and 1.5 and it was ∼2 for oxides with x = 0.5, 0.75, and 1.0. Suitable reaction mechanisms consistent with the electrode kinetic parameters have also been proposed.
authors.affiliation: Department of Chemistry, Centre of Advanced Study, Faculty of Science, Banaras Hindu University, Varanasi-221005, India. rnsbhu@rediffmail.com rnsbhu@gmail.com.
authors.forename: Venkata Kali Vara Prasad
authors.initials: VK
authors.lastname: Srirapu
authors.forename: Chandra Shekhar
authors.initials: CS
authors.lastname: Sharma
authors.forename: Rahul
authors.initials: R
authors.lastname: Awasthi
authors.forename: Ravindra Nath
authors.initials: RN
authors.lastname: Singh
authors.forename: Akhoury Sudhir Kumar
authors.initials: AS
authors.lastname: Sinha