{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T20:27:18Z","timestamp":1792009638219,"version":"4.4.0"},"reference-count":84,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2020,5,21]],"date-time":"2020-05-21T00:00:00Z","timestamp":1590019200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100012818","name":"Comunidad de Madrid","doi-asserted-by":"publisher","award":["2017-T1\/IND-6025"],"award-info":[{"award-number":["2017-T1\/IND-6025"]}],"id":[{"id":"10.13039\/100012818","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Nanomaterials"],"abstract":"<jats:p>Nanostructured composite materials based on noble mono-(Pd) or bi-metallic (Ag\/Pd) particles supported on mixed iron oxides (II\/III) with bulk magnetite structure (Fe3O4) have been developed in order to assess their potential for heterogeneous catalysis applications in methane partial oxidation. Advancing the direct transformation of methane into value-added chemicals is consensually accepted as the key to ensuring sustainable development in the forthcoming future. On the one hand, nanosized Fe3O4 particles with spherical morphology were synthesized by an aqueous-based reflux method employing different Fe (II)\/Fe (III) molar ratios (2 or 4) and reflux temperatures (80, 95 or 110 \u00b0C). The solids obtained from a Fe (II)\/Fe (III) nominal molar ratio of 4 showed higher specific surface areas which were also found to increase on lowering the reflux temperature. The starting 80 m2 g\u22121 was enhanced up to 140 m2 g\u22121 for the resulting optimized Fe3O4-based solid consisting of nanoparticles with a 15 nm average diameter. On the other hand, Pd or Pd-Ag were incorporated post-synthesis, by impregnation on the highest surface Fe3O4 nanostructured substrate, using 1\u20133 wt.% metal load range and maintaining a constant Pd:Ag ratio of 8:2 in the bimetallic sample. The prepared nanocomposite materials were investigated by different physicochemical techniques, such as X-ray diffraction, thermogravimetry (TG) in air or H2, as well as several compositions and structural aspects using field emission scanning and scanning transmission electron microscopy techniques coupled to energy-dispersive X-ray spectroscopy (EDS). Finally, the catalytic results from a preliminary reactivity study confirmed the potential of magnetite-supported (Ag)Pd catalysts for CH4 partial oxidation into formaldehyde, with low reaction rates, methane conversion starting at 200 \u00b0C, far below temperatures reported in the literature up to now; and very high selectivity to formaldehyde, above 95%, for Fe3O4 samples with 3 wt.% metal, either Pd or Pd-Ag.<\/jats:p>","DOI":"10.3390\/nano10050988","type":"journal-article","created":{"date-parts":[[2020,5,21]],"date-time":"2020-05-21T11:31:18Z","timestamp":1590060678000},"page":"988","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":13,"title":["(Ag)Pd-Fe3O4 Nanocomposites as Novel Catalysts for Methane Partial Oxidation at Low Temperature"],"prefix":"10.3390","volume":"10","author":[{"given":"Blanca","family":"Mart\u00ednez-Navarro","sequence":"first","affiliation":[{"name":"Departmento de Qu\u00edmica Inorg\u00e1nica y Qu\u00edmica T\u00e9cnica, Facultad de Ciencias, UNED, Paseo Senda del Rey, 9, 28040 Madrid, Spain"},{"name":"Instituto de Cat\u00e1lisis y Petroleoqu\u00edmica (ICP-CSIC), C\/Marie Curie, 2, Cantoblanco, 28049 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ruth","family":"Sanchis","sequence":"additional","affiliation":[{"name":"Departmento de Ingenier\u00eda Qu\u00edmica, Universitat de Val\u00e8ncia, C\/Dr. Moliner 50, Burjassot, 46100 Valencia, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Esther","family":"Asedegbega-Nieto","sequence":"additional","affiliation":[{"name":"Departmento de Qu\u00edmica Inorg\u00e1nica y Qu\u00edmica T\u00e9cnica, Facultad de Ciencias, UNED, Paseo Senda del Rey, 9, 28040 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7235-2038","authenticated-orcid":false,"given":"Benjam\u00edn","family":"Solsona","sequence":"additional","affiliation":[{"name":"Departmento de Ingenier\u00eda Qu\u00edmica, Universitat de Val\u00e8ncia, C\/Dr. Moliner 50, Burjassot, 46100 Valencia, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5896-7623","authenticated-orcid":false,"given":"Francisco","family":"Ivars-Barcel\u00f3","sequence":"additional","affiliation":[{"name":"Departmento de Qu\u00edmica Inorg\u00e1nica y Qu\u00edmica T\u00e9cnica, Facultad de Ciencias, UNED, Paseo Senda del Rey, 9, 28040 Madrid, Spain"},{"name":"Instituto de Cat\u00e1lisis y Petroleoqu\u00edmica (ICP-CSIC), C\/Marie Curie, 2, Cantoblanco, 28049 Madrid, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,5,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"428","DOI":"10.1038\/348428a0","article-title":"Control of product selectivity in the partial oxidation of methane","volume":"348","author":"Hargreaves","year":"1990","journal-title":"Nature"},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Zhao, G., Drewery, M., Mackie, J., Oliver, T., Kennedy, E.M., and Stockenhuber, M. (2019). The Catalyzed Conversion of Methane to Value-Added Products. Energy Technol., 1900665.","DOI":"10.1002\/ente.201900665"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"5111","DOI":"10.1039\/C9CY01055F","article-title":"Understanding trends in methane oxidation to formaldehyde: Statistical analysis of literature data and based hereon experiments","volume":"9","author":"Fait","year":"2019","journal-title":"Catal. Sci. Technol."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"124","DOI":"10.1006\/jcat.1993.1124","article-title":"The Partial Oxidation of Methane to Formaldehyde: Role of Different Crystal Planes of MoO3","volume":"141","author":"Smith","year":"1993","journal-title":"J. Catal."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"87","DOI":"10.1002\/aic.690370108","article-title":"Simulation of methane partial oxidation over silica-supported MoO3 and V2O5","volume":"37","author":"Amiridis","year":"1991","journal-title":"Aiche J."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"559","DOI":"10.1016\/0920-5861(90)85052-P","article-title":"Oxidation of methane to formaldehyde over supported molybdena catalysts at ambient pressure: Isolation of the selective oxidation product","volume":"6","author":"Kennedy","year":"1990","journal-title":"Catal. Today"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1007\/BF00765197","article-title":"Effect of surface species on activity and selectivity of MoO3\/SiO2 catalysts in partial oxidation of methane to formaldehyde","volume":"19","author":"Smith","year":"1993","journal-title":"Catal. Lett."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"521","DOI":"10.1134\/S1070427209040016","article-title":"Catalytic partial oxidation of methane to formaldehyde","volume":"82","author":"Marakaev","year":"2009","journal-title":"Russ. J. Appl. Chem."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"27436","DOI":"10.1021\/acs.jpcc.9b04388","article-title":"Comparison of Direct, Selective Oxidation of Methane by N2O over Fe-ZSM-5, Fe-\u03b2eta, and Fe-FER Catalysts","volume":"123","author":"Zhao","year":"2019","journal-title":"J. Phys. Chem. C"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"864","DOI":"10.1016\/j.catcom.2007.09.013","article-title":"Methane selective oxidation to formaldehyde with Fe-catalysts supported on silica or incorporated into the support","volume":"9","author":"Fajardo","year":"2008","journal-title":"Catal. Commun."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1016\/S0920-5861(96)00173-3","article-title":"Oxidation of methane to formaldehyde over FeSiO2 and Sn-W mixed oxides","volume":"32","author":"Kobayashi","year":"1996","journal-title":"Catal. Today"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"305","DOI":"10.1016\/0920-5861(91)80056-F","article-title":"Progress in the partial oxidation of methane to methanol and formaldehyde","volume":"8","author":"Brown","year":"1991","journal-title":"Catal. Today"},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"43","DOI":"10.1021\/bk-1993-0523.ch004","article-title":"Silica-Supported MoO3 and V2O5 Catalysts in Partial Oxidation of Methane to Formaldehyde","volume":"Volume 523","author":"Parmaliana","year":"1993","journal-title":"Catalytic Selective Oxidation"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"288","DOI":"10.1016\/S1003-9953(08)60120-6","article-title":"Selective oxidation of methane to formaldehyde by oxygen over silica-supported iron catalysts","volume":"18","author":"He","year":"2009","journal-title":"J. Nat. Gas Chem."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1016\/S0926-860X(01)00897-3","article-title":"Effect of Fe-addition on the catalytic activity of silicas in the partial oxidation of methane to formaldehyde","volume":"226","author":"Parmaliana","year":"2002","journal-title":"Appl. Catal. A Gen."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"365","DOI":"10.1016\/j.jcat.2005.01.029","article-title":"Structure and reactivity in the selective oxidation of methane to formaldehyde of low-loaded FeOx \/SiO2 catalysts","volume":"231","author":"Arena","year":"2005","journal-title":"J. Catal."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"156","DOI":"10.1016\/j.cattod.2006.05.018","article-title":"Iron-containing heterogeneous catalysts for partial oxidation of methane and epoxidation of propylene","volume":"117","author":"Wang","year":"2006","journal-title":"Catal. Today"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"44","DOI":"10.1016\/j.apcata.2019.03.014","article-title":"Effects of promoters on the performance of a VOx\/SiO2 catalyst for the oxidation of methane to formaldehyde","volume":"577","author":"Shimura","year":"2019","journal-title":"Appl. Catal. A Gen."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1016\/S0920-5861(98)00236-3","article-title":"Direct conversion of methane into methanol over MoO3\/SiO2 catalyst in an excess amount of water vapor","volume":"45","author":"Aoki","year":"1998","journal-title":"Catal. Today"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"673","DOI":"10.1021\/j100105a023","article-title":"Carbon pathways for the partial oxidation of methane","volume":"97","author":"Koranne","year":"1993","journal-title":"J. Phys. Chem."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"208","DOI":"10.1246\/cl.2003.208","article-title":"Simple Preparation Method of Isolated Iron (III) Species on Silica Surface","volume":"32","author":"Yamada","year":"2003","journal-title":"Chem. Lett."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1016\/S0920-5861(01)00439-4","article-title":"Selective oxidation of light alkanes to aldehydes over silica catalysts supporting mononuclear active sites - Acrolein formation from ethane","volume":"71","author":"Kobayashi","year":"2001","journal-title":"Catal. Today"},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1377","DOI":"10.1016\/S0016-2361(03)00038-3","article-title":"Direct conversion of methane to acetylene or syngas at room temperature using non-equilibrium pulsed discharge","volume":"82","author":"Kado","year":"2003","journal-title":"Fuel"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"5129","DOI":"10.1002\/anie.201108706","article-title":"Direct Catalytic Conversion of Methane to Methanol in an Aqueous Medium by using Copper-Promoted Fe-ZSM-5","volume":"51","author":"Hammond","year":"2012","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"3703","DOI":"10.1002\/anie.201200015","article-title":"Direct Conversion of Methane into Formaldehyde Mediated by [Al2O3]\u00b7+ at Room Temperature","volume":"51","author":"Wang","year":"2012","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_26","doi-asserted-by":"crossref","unstructured":"Grunwaldt, J.-D., van Vegten, N., and Baiker, A. (2007). Insight into the structure of supported palladium catalysts during the total oxidation of methane. Chem. Commun., 4635\u20134637.","DOI":"10.1039\/b710222d"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/j.apcatb.2004.03.009","article-title":"Total oxidation of methane at low temperature over Pd\/TiO2\/Al2O3: Effects of the support and residual chlorine ions","volume":"50","author":"Lin","year":"2004","journal-title":"Appl. Catal. B Environ."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"2303","DOI":"10.1021\/acscatal.8b04486","article-title":"Design of Stable Palladium-Based Zeolite Catalysts for Complete Methane Oxidation by Postsynthesis Zeolite Modification","volume":"9","author":"Petrov","year":"2019","journal-title":"Acs Catal."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"8587","DOI":"10.1021\/jp212236e","article-title":"Combustion of Methane over Palladium-Based Catalysts: Catalytic Deactivation and Role of the Support","volume":"116","author":"Schwartz","year":"2012","journal-title":"J. Phys. Chem. C"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1849","DOI":"10.1016\/j.susc.2006.02.016","article-title":"Alumina supported model Pd\u2013Ag catalysts: A combined STM, XPS, TPD and IRAS study","volume":"600","author":"Khan","year":"2006","journal-title":"Surf. Sci."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"6852","DOI":"10.1021\/jp071584v","article-title":"On the Promoting Role of Ag in Selective Hydrogenation Reactions over Pd\u2212Ag Bimetallic Catalysts:\u2009 A Theoretical Study","volume":"111","author":"Neyman","year":"2007","journal-title":"J. Phys. Chem. C"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"671","DOI":"10.1038\/nmeth.2089","article-title":"NIH Image to ImageJ: 25 years of image analysis","volume":"9","author":"Schneider","year":"2012","journal-title":"Nat. Methods"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"873","DOI":"10.1002\/(SICI)1097-4555(199711)28:11<873::AID-JRS177>3.0.CO;2-B","article-title":"Raman microspectroscopy of some iron oxides and oxyhydroxides","volume":"28","year":"1997","journal-title":"J. Raman Spectrosc."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"845","DOI":"10.1002\/jrs.1056","article-title":"Raman study of magnetite (Fe3O4): Laser-induced thermal effects and oxidation","volume":"34","author":"Shebanova","year":"2003","journal-title":"J. Raman Spectrosc."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"117","DOI":"10.1016\/j.vibspec.2007.07.003","article-title":"Heated goethite and natural hematite: Can Raman spectroscopy be used to differentiate them?","volume":"45","author":"Lopes","year":"2007","journal-title":"Vib. Spectrosc."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"1543","DOI":"10.1016\/j.jmmm.2011.11.065","article-title":"Infrared and Raman spectroscopic studies on iron oxide magnetic nano-particles and their surface modifications","volume":"324","author":"Li","year":"2012","journal-title":"J. Magn. Magn. Mater."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"012022","DOI":"10.1088\/1742-6596\/304\/1\/012022","article-title":"Properties of magnetic iron oxides used as materials for wastewater treatment","volume":"304","author":"Matei","year":"2011","journal-title":"J. Phys. Conf. Ser."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"283","DOI":"10.1016\/S0012-821X(99)00033-3","article-title":"Dissolution behaviour of fine-grained magnetite and maghemite in the citrate\u2013bicarbonate\u2013dithionite extraction method","volume":"167","author":"Dekkers","year":"1999","journal-title":"Earth Planet. Sci. Lett."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"8320","DOI":"10.1039\/c0jm01274b","article-title":"Assembly of magnetite nanocrystals into spherical mesoporous aggregates with a 3-D wormhole-like pore structure","volume":"20","author":"Yu","year":"2010","journal-title":"J. Mater. Chem."},{"key":"ref_40","first-page":"21","article-title":"The infrared dielectric properties of maghemite, \u03b3-Fe2O3, from reflectance measurement on pressed powders","volume":"22","author":"Iglesias","year":"1995","journal-title":"Phys. Chem. Miner."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"105940","DOI":"10.1039\/C6RA21691A","article-title":"Monodisperse AgPd alloy nanoparticles as a highly active catalyst towards the methanolysis of ammonia borane for hydrogen generation","volume":"6","author":"Sun","year":"2016","journal-title":"Rsc Adv."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"16122","DOI":"10.1039\/C9TA00664H","article-title":"Nanoalloying effects on the catalytic activity of the formate oxidation reaction over AgPd and AgCuPd aerogels","volume":"7","author":"Wang","year":"2019","journal-title":"J. Mater. Chem. A"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"1212","DOI":"10.1021\/sc500034r","article-title":"Plant-Mediated Synthesis of Ag\u2013Pd Alloy Nanoparticles and Their Application as Catalyst toward Selective Hydrogenation","volume":"2","author":"Lu","year":"2014","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"13891","DOI":"10.1039\/C9NJ01733J","article-title":"Plant-mediated synthesis of AgPd\/\u03b3-Al2O3 catalysts for selective hydrogenation of 1,3-butadiene at low temperature","volume":"43","author":"Lu","year":"2019","journal-title":"New J. Chem."},{"key":"ref_45","unstructured":"America, I.S.M.S.O. (1989). Modern powder diffraction. Reviews in Mineralogy & Geochemistry, De Gruyter."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"186","DOI":"10.1016\/j.ijbiomac.2018.02.120","article-title":"Pd(II)\/Pd(0) anchored to magnetic nanoparticles (Fe3O4) modified with biguanidine-chitosan polymer as a novel nanocatalyst for Suzuki-Miyaura coupling reactions","volume":"113","author":"Veisi","year":"2018","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"3951","DOI":"10.1016\/j.ceramint.2017.11.187","article-title":"Preparation and characterization of magnetic \u03b3-Al2O3 ceramic nanocomposite particles with variable Fe3O4 content and modification with epoxide functional polymer","volume":"44","author":"Bristy","year":"2018","journal-title":"Ceram. Int."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"246","DOI":"10.1039\/C6CE02421A","article-title":"Oxidation of magnetite nanoparticles: Impact on surface and crystal properties","volume":"19","author":"Schwaminger","year":"2017","journal-title":"CrystEngComm"},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"1247","DOI":"10.1109\/TMAG.1981.1061188","article-title":"Preparation of aqueous magnetic liquids in alkaline and acidic media","volume":"17","author":"Massart","year":"1981","journal-title":"IEEE Trans. Magn."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"497","DOI":"10.1016\/0010-938X(91)90103-V","article-title":"Raman studies of corrosion films grown on Fe and Fe-6Mo in pitting conditions","volume":"32","author":"Boucherit","year":"1991","journal-title":"Corros. Sci."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"1395","DOI":"10.1039\/b419004a","article-title":"Molecular composition of iron oxide nanoparticles, precursors for magnetic drug targeting, as characterized by confocal Raman microspectroscopy","volume":"130","author":"Chourpa","year":"2005","journal-title":"Analyst"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"166300","DOI":"10.1016\/j.jmmm.2019.166300","article-title":"Novel scanning magnetic microscopy method for the characterization of magnetic nanoparticles","volume":"499","author":"Araujo","year":"2020","journal-title":"J. Magn. Magn. Mater."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.colsurfa.2008.07.044","article-title":"One step grafting of monomethoxy poly(ethylene glycol) during synthesis of maghemite nanoparticles in aqueous medium","volume":"330","author":"Hu","year":"2008","journal-title":"Colloids Surf. A Physicochem. Eng. Asp."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"225","DOI":"10.1039\/C0NR00521E","article-title":"Size-dependent properties of magnetic iron oxide nanocrystals","volume":"3","author":"Panissod","year":"2011","journal-title":"Nanoscale"},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"64919","DOI":"10.1039\/C4RA11283K","article-title":"Magnetic, X-ray and M\u00f6ssbauer studies on magnetite\/maghemite core-shell nanostructures fabricated through an aqueous route","volume":"4","author":"Iyengar","year":"2014","journal-title":"RSC Adv."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"5869","DOI":"10.1021\/cm801405n","article-title":"Coupling Agent Effect on Magnetic Properties of Functionalized Magnetite-Based Nanoparticles","volume":"20","author":"Daou","year":"2008","journal-title":"Chem. Mater."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"7539","DOI":"10.1039\/c3ce40873f","article-title":"Growth defects and epitaxy in Fe3O4 and \u03b3-Fe2O3 nanocrystals","volume":"15","year":"2013","journal-title":"CrystEngComm"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1016\/0010-938X(94)00102-C","article-title":"A surface-enhanced Raman spectroscopic study of the passive films formed in borate buffer on iron, nickel, chromium and stainless steel","volume":"37","author":"Oblonsky","year":"1995","journal-title":"Corros. Sci."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"426","DOI":"10.1006\/jcat.1998.2069","article-title":"Iron-Oxide Supported Gold Catalysts Derived from Gold-Phosphine Complex Au(PPh3)(NO3): State and Structure of the Support","volume":"176","author":"Kozlova","year":"1998","journal-title":"J. Catal."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"424","DOI":"10.1016\/S0022-4596(03)00294-9","article-title":"Raman spectroscopic study of magnetite (FeFe2O4): A new assignment for the vibrational spectrum","volume":"174","author":"Shebanova","year":"2003","journal-title":"J. Solid State Chem."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"941","DOI":"10.1111\/j.1365-246X.2009.04122.x","article-title":"Raman spectroscopy of iron oxides and (oxy)hydroxides at low laser power and possible applications in environmental magnetic studies","volume":"177","author":"Hanesch","year":"2009","journal-title":"Geophys. J. Int."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"4965","DOI":"10.1021\/jp048748h","article-title":"Infrared- and Raman-Active Phonons of Magnetite, Maghemite, and Hematite: A Computer Simulation and Spectroscopic Study","volume":"109","author":"Chamritski","year":"2005","journal-title":"J. Phys. Chem. B"},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"1736","DOI":"10.1039\/b618790k","article-title":"Size-dependent structural transformations of hematite nanoparticles. 1. Phase transition","volume":"9","author":"Chernyshova","year":"2007","journal-title":"Phys. Chem. Chem. Phys."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"476","DOI":"10.5006\/1.3583054","article-title":"Raman Spectroscopy of Thin Corrosion Films on Iron at 100 to 150 \u2261C in Air","volume":"42","author":"Ohtsuka","year":"1986","journal-title":"Corrosion"},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"2086","DOI":"10.1039\/C9NA00064J","article-title":"Raman spectroscopy to unravel the magnetic properties of iron oxide nanocrystals for bio-related applications","volume":"1","year":"2019","journal-title":"Nanoscale Adv."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"2804","DOI":"10.1021\/am1004943","article-title":"Vibrational Spectroscopic Characterization of Hematite, Maghemite, and Magnetite Thin Films Produced by Vapor Deposition","volume":"2","author":"Jubb","year":"2010","journal-title":"Acs Appl. Mater. Interfaces"},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"355","DOI":"10.1002\/(SICI)1097-4555(199905)30:5<355::AID-JRS398>3.0.CO;2-C","article-title":"Micro-Raman investigation of iron oxide films and powders produced by sol-gel syntheses","volume":"30","author":"Bersani","year":"1999","journal-title":"J. Raman Spectrosc."},{"key":"ref_68","doi-asserted-by":"crossref","unstructured":"Marshall, C.P., Dufresne, W.J.B., and Rufledt, C.J. (2020). Polarized Raman spectra of hematite and assignment of external modes. J. Raman Spectrosc.","DOI":"10.1002\/jrs.5824"},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"10662","DOI":"10.1021\/acs.jpcc.5b00819","article-title":"Improvement of Thermal Stability of Maghemite Nanoparticles Coated With Oleic Acid and Oleylamine Molecules: Investigations Under Laser Irradiation","volume":"119","author":"Grasset","year":"2015","journal-title":"J. Phys. Chem. C"},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"4063","DOI":"10.1007\/s11051-011-0350-y","article-title":"Synthesis, characterization and role of zero-valent iron nanoparticle in removal of hexavalent chromium from chromium-spiked soil","volume":"13","author":"Singh","year":"2011","journal-title":"J. Nanopart. Res."},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"661","DOI":"10.1107\/S0365110X53001800","article-title":"The structure of PdO","volume":"6","author":"Waser","year":"1953","journal-title":"Acta Crystallogr."},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"4607","DOI":"10.1039\/c0cp01331e","article-title":"In situ Raman and in situ XRD analysis of PdO reduction and Pd\u00b0 oxidation supported on \u03b3-Al2O3 catalyst under different atmospheres","volume":"13","author":"Baylet","year":"2011","journal-title":"Phys. Chem. Chem. Phys. PCCP"},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"1048","DOI":"10.2320\/matertrans.M2010429","article-title":"Synthesis of Palladium Nanoparticles and Palladium\/Spherical Carbon Composite Particles in the Solid-Liquid System of Palladium Oxide-Alcohol by Microwave Irradiation","volume":"52","author":"Sekiguchi","year":"2011","journal-title":"Mater. Trans."},{"key":"ref_74","unstructured":"(1991). Formaldehyde Health and Safety Guide, World Health Organization. IPCS International Programme on Chemical Safety Health and Safety Guide No. 57."},{"key":"ref_75","doi-asserted-by":"crossref","first-page":"185","DOI":"10.1023\/A:1019071911630","article-title":"Low-temperature oxidation of methane to form formaldehyde: Role of Fe and Mo on Fe\u2013Mo\/SiO2 catalysts, and their synergistic effects","volume":"64","author":"Yang","year":"2000","journal-title":"Catal. Lett."},{"key":"ref_76","doi-asserted-by":"crossref","first-page":"149","DOI":"10.1016\/j.cattod.2010.02.007","article-title":"Oxidation of methane and ethylene in water at ambient conditions","volume":"157","author":"Sorokin","year":"2010","journal-title":"Catal. Today"},{"key":"ref_77","doi-asserted-by":"crossref","first-page":"2782","DOI":"10.1002\/1521-3773(20010803)40:15<2782::AID-ANIE2782>3.0.CO;2-P","article-title":"Dioxygen Activation and Methane Hydroxylation by Soluble Methane Monooxygenase: A Tale of Two Irons and Three Proteins","volume":"40","author":"Merkx","year":"2001","journal-title":"Angew. Chem. Int. Ed."},{"key":"ref_78","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1016\/S0926-860X(03)00262-X","article-title":"High throughput experiments on methane partial oxidation using molecular oxygen over silica doped with various elements","volume":"254","author":"Yamada","year":"2003","journal-title":"Appl. Catal. A Gen."},{"key":"ref_79","doi-asserted-by":"crossref","first-page":"13","DOI":"10.1080\/03602458608068085","article-title":"Partial Oxidation of Methane","volume":"28","author":"Pitchai","year":"1986","journal-title":"Catal. Rev."},{"key":"ref_80","doi-asserted-by":"crossref","first-page":"80","DOI":"10.1016\/j.jcat.2005.09.023","article-title":"Selective hydrogenation of \u03b1,\u03b2-unsaturated ketone to \u03b1,\u03b2-unsaturated alcohol on gold-supported iron oxide catalysts: Role of the support","volume":"236","author":"Milone","year":"2005","journal-title":"J. Catal."},{"key":"ref_81","doi-asserted-by":"crossref","first-page":"17","DOI":"10.1016\/j.apcata.2007.03.021","article-title":"Reduction behavior of iron oxides in hydrogen and carbon monoxide atmospheres","volume":"326","author":"Jozwiak","year":"2007","journal-title":"Appl. Catal. A Gen."},{"key":"ref_82","doi-asserted-by":"crossref","first-page":"233","DOI":"10.1007\/BF03353787","article-title":"Preparation of Palladium Supported on Ferric Oxide Nano-catalysts for Carbon Monoxide Oxidation in Low Temperature","volume":"6","author":"Wang","year":"2014","journal-title":"Nano-Micro Lett."},{"key":"ref_83","doi-asserted-by":"crossref","first-page":"705","DOI":"10.1038\/nature01557","article-title":"Dissociative hydrogen adsorption on palladium requires aggregates of three or more vacancies","volume":"422","author":"Mitsui","year":"2003","journal-title":"Nature"},{"key":"ref_84","doi-asserted-by":"crossref","first-page":"356","DOI":"10.1007\/s11467-009-0050-6","article-title":"Hydrogen adsorption and desorption on the Pt and Pd subnano clusters\u2014A review","volume":"4","author":"Chen","year":"2009","journal-title":"Front. Phys. China"}],"container-title":["Nanomaterials"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2079-4991\/10\/5\/988\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T09:31:07Z","timestamp":1760175067000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2079-4991\/10\/5\/988"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,5,21]]},"references-count":84,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2020,5]]}},"alternative-id":["nano10050988"],"URL":"https:\/\/doi.org\/10.3390\/nano10050988","relation":{},"ISSN":["2079-4991"],"issn-type":[{"value":"2079-4991","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,5,21]]}}}