137 ISSN 1995-0780, Nanotechnologies in Russia, 2016, Vol. 11, Nos. 3–4, pp. 137–143. © Pleiades Publishing, Ltd., 2016. Original Russian Text © L.I. Kuklo, S.I. Belyaninova, S.S. Ermakov, V.P. Tolstoy, 2016, published in Rossiiskie Nanotekhnologii, 2016, Vol. 11, Nos. 3–4. Fe 0.5 MnO x · nH 2 O Nanolayers Synthesized via Successive Ionic Layer Deposition and Their Use in Voltammetric Nonenzymatic Determination of Hydrogen Peroxide L. I. Kuklo, S. I. Belyaninova, S. S. Ermakov, and V. P. Tolstoy Institute of Chemistry, St. Petersburg State University, Universitetskii pr. 26, Petrodvorets, St. Petersburg, 198504 Russia e-mail: lenkuklo@mail.ru Received August 15, 2015; in final form, December 14, 2015 Abstract—In this work, the ability to synthesize the mixed iron–manganese oxide nanolayers via SILD has been shown. Aqueous solutions of potassium ferrate and manganese acetate have been served as the reagents for such synthesis. The layers have been probed via scanning electron microscopy, X-ray microanalysis, X-ray dif- fraction, X-ray photoelectron spectroscopy, and UV-Vis and FTIR spectroscopy. The hydrated amorphous Fe 0.5 MnO x ⋅ nH 2 O layers with nanoparticle sizes of 10–20 nm have been detected at the surface, where the Fe/Mn content ratio is 0.5 and thickness increases with the number of layering cycles. The experimental data have allowed one to assume the chemical reactions occurring on the surface upon synthesis. The synthesized layers have been tested as electrodes in the voltammetric determination of H 2 O 2 concentration, and the most effective electrodes are found to be those obtained after 30 SILD cycles. For them, the linear dependence of a sensor response for H 2 O 2 solutions is found to be over the concentration range of 1 × 10 –8 –5 × 10 –8 М. It has also been assumed that the synthesized layers can be applied as the sorbents for purification of gases and liquids; catalysts for oxidation of organic compounds, CO and NO; electrodes of chemical current sources; and so on. DOI: 10.1134/S1995078016020105 INTRODUCTION Double iron and manganese oxides are known to be formed by iron atoms with a degree of oxidation of 2+ and 3+ and by manganese atoms in the oxidation state of 2+, 3+, and 4+. This feature defines the prac- tical importance of oxides which serve as catalysts in the oxidation of organic compounds and ozone decomposition [1], impulse oxygen sources [2] and one of the reagents in the thermochemical cycle during the production of hydrogen [3]. Other applica- tions of these oxides are as electrodes for supercapaci- tors [4] and lithium–ionic current sources [5], mag- netic materials [6], and sorbents for the removal of arsenites and selenites from aqueous solutions [7, 8]. The mixed iron–manganese oxides can be obtained via sintering [2, 3], hydrothermal methods [1, 8], ultrasonic treatment of solutions [9], precipita- tion from solutions [7], microemulsions [10] and at the electrode surface [4], sole–gel technology [6], and other methods. Nevertheless, no works on the layer-by-layer syn- thesis of these compounds have yet been reported. These methods are in the subsequent and multiple adsorptions from low-dimensional building blocks solutions on the substrate, which results in the forma- tion of a nanolayer with a thickness of a nanometer or even less. The advantages of layer-by-layer technology are the abilities to obtain layers on the complex sub- strate surface and precision control of their thickness, i.e., goals of preparative chemistry in the fabrication of new catalysts, sorbents, sensors, and membranes. As is known, the layer-by-layer synthesis involving molecules as reagents can be implemented via atomic layer deposition [11, 12] (ALD). If when using salt solutions during synthesis their cations and anions compose the layer, this is related to ionic deposition (ID) [13] or polyionic assembling [14], as well as Layer-by-Layer (LbL) [15], Successive Ionic Layer Adsorption and Reaction (SILAR) [16], or Successive Ionic Layer Deposition (SILD) [17]. To synthesize oxides via this method, the redox reactions were previously proposed, leading to the for- mation of adsorbed Mn 2+ cations with air oxygen of Mn 3 O 4 layer [18], Ag + cations with Mn 2+ cations of Ag x MnO y ⋅ nH 2 O layer [19], Ce 3+ with H 2 O 2 (OH – )– Ce x La(OOH) 3+3x [20], Sn 2+ with Mo –Sn x MoO y ⋅ nH 2 O [21], Sn 2+ with Ag + –Ag x SnO 2 ⋅ nH 2 O [22], Fe 2+ with Cr –Cr x Fe(OH) 3+3x [23], Ag + with H 2 O 2 (OH – )–Ag 0 [24, 25], and so on. -2 4 O -2 4 O