title: Cathodic electrodeposition of mixed molybdenum tungsten oxides from peroxo-polymolybdotungstate solutions.
abstract: Mixed molybdenum tungsten trioxide films of varying stoichiometry (MoxW1 - xO3, 0 < x < 1) were prepared by cathodic electrodeposition on indium tin oxide (ITO)-coated glass substrates from aqueous peroxo-polymolybdotungstate solutions. Electrochemical quartz crystal microbalance (EQCM), cyclic voltammetry, and chronocoulometry were used to gain insight into the electrodeposition mechanism. The compositional and structural properties were characterized for MoxW1 - xO3 films deposited at intermediate potentials (-0.35 V vs Ag/AgCl) and sintered at 250 degrees C using energy-dispersive spectroscopy, X-ray diffraction, and Raman spectroscopy. These studies reveal that films consist of homogeneously mixed MoxW1 - xO3, with an enriched Mo content ranging in composition from 0.4 < x < 0.7 depending upon the mol % Mo present in the deposition solution. Chronoamperometry and spectroelectrochemical measurements were conducted to estimate lithium ion diffusion coefficients and coloration efficiencies for the mixed metal oxide films in 1 M LiClO4/propylene carbonate. The subtle interplay between structural and compositional properties due to the uniform mixing of Mo and W oxide components shows that electrochromic and lithium ion transport properties are moderately enhanced relative to those of single-component WO3 and MoO3 and demonstrate improved structural stability over pure MoO3 polymorphs during electrochemical cycling.
authors.affiliation: Department of Chemistry and Biochemistry, Center for Nano- and Molecular Science and Technology, Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Lilia
authors.initials: L
authors.lastname: Kondrachova
authors.forename: Benjamin P
authors.initials: BP
authors.lastname: Hahn
authors.forename: Ganesh
authors.initials: G
authors.lastname: Vijayaraghavan
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Williams
authors.forename: Keith J
authors.initials: KJ
authors.lastname: Stevenson
mesh_terms: D002412:Cations / Q000737:chemistry; D003460:Crystallization; D004563:Electrochemistry; D004566:Electrodes; D008567:Membranes, Artificial; D008832:Microchemistry; D008982:Molybdenum / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D011791:Quartz / Q000737:chemistry; D012996:Solutions / Q000737:chemistry; D013499:Surface Properties; D017971:Tin Compounds / Q000737:chemistry; D014414:Tungsten / Q000737:chemistry*
chemical_list: D002412:Cations; D008567:Membranes, Artificial; D010087:Oxides; D012996:Solutions; D017971:Tin Compounds; D011791:Quartz; D008982:Molybdenum; C511604:tungsten oxide; C045358:stannic oxide; D014414:Tungsten