reprint Fe2O3 Pt ESI

Iron(III) oxide systems were fabricated by means of a custom-built two-electrode plasma enhanced-chemical vapor deposition (PE-CVD) apparatus (Radio Frequency = 13.56 MHz; electrode diameter = 9 cm; inter-electrode distance = 6 cm). 1-3 The iron precursor Fe(hfa) 2 TMEDA (hfa = 1,1,1,5,5, TMEDA = N,N,N', was synthesized as previously reported. 4-5 In a typical growth experiment, 0.30 ± 0.01 g of precursor powders were placed in an external glass reservoir, heated by an oil bath at 65 °C, and transported into the reaction chamber by electronic grade Ar (flow rate = 60 sccm). Connection gas lines were maintained at 140 °C by means of external heating tapes, to prevent undesired precursor condensation phenomena. Two additional gas lines were used to introduce electronic grade Ar and O 2 (flow rates = 15 and 20 sccm, respectively) directly into the reaction chamber.

Phys. Chem. Chem. Phys., 2015

Electronic Supplementary Material (ESI) for Physical Chemistry Chemical Physics. This journal is © the Owner Societies 2015 2 EXPERIMENTAL DETAILS Synthesis. Fe 2 O 3 deposits were fabricated by means of a custom-built PE-CVD apparatus equipped with a radio frequency (RF, ν = 13.56 MHz) generator. 1 The diameter of each electrode was 9 cm and the inter-electrode distance was fixed at 6 cm. Growth experiments were performed from Ar/O 2 plasmas for a total duration of 1 h, using a fixed RF-power of 10 W and a total pressure of 1.0 mbar. The iron precursor Fe(hfa) 2 TMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA = N,N,N',N'-tetramethylethylenediamine), synthesized according to a previously reported procedure, 2,3 was placed in an external vessel heated by an oil bath maintained at 65 °C and transported into the reaction chamber by means of electronic grade Ar (flow rate = 60 sccm). The temperature of precursor feeding lines was maintained at 140 °C in order to prevent detrimental condensation phenomena. Two further auxiliary gas-lines were used to introduce Ar (flow rate = 15 sccm) and electronic grade O 2 (flow rate = 20 sccm) directly into the reactor chamber. Basing on previous results, 4 Fe 2 O 3 growth was performed at 300 °C on FTO-coated glass slides (Aldrich, 735167-1EA, 7 Ω/sq; lateral dimensions = 2.0 cm  1.0 cm; FTO thickness 600 nm), mounted on the grounded electrode. Prior to deposition, the substrates were suitably cleaned by iterative dipping in acetone, sulphonic detergent, distilled water, and finally dried under an air flow.

Physical chemistry chemical physics : PCCP, 2015

An iron(iii) β-diketonate complex, Fe(dpm)3 (Hdpm = 2,2,6,6-tetramethyl-3,5-heptanedione), has been investigated as a potential precursor for plasma enhanced chemical vapor deposition (PECVD) of iron(iii) oxide nanomaterials. Thanks to the combined experimental-theoretical approach, spectroscopic properties, spin state, thermal behavior and fragmentation pathways of Fe(dpm)3 have been carefully analysed, obtaining an excellent agreement between simulation and experiment. Preliminary PECVD tests evidenced the possibility of obtaining pure and homogeneous Fe2O3 deposits with controlled nano-organization at temperatures as low as 100 °C, even on flexible plastic substrates. The present results open up intriguing perspectives for the exploitation of Fe(dpm)3 as an efficient molecular source for the preparation of nanostructured iron(iii) oxides to be used in energetics and gas sensing applications.

2012

Supported b-Fe 2 O 3 systems were grown and functionalized with Ag or Pt nanoparticles (NPs) adopting a two-step synthetic strategy. Iron oxide matrices (host) were initially deposited by thermal Chemical Vapor Deposition (CVD) using Fe(hfa) 2 ÁTMEDA (hfa = 1,1,1,5,5,5-hexafluoro-2,4-pentanedionate; TMEDA = N,N,N',N'-tetramethylethylenediamine) as precursor, at a growth temperature of 400 C and total pressure of 3.0 mbar. Subsequently, Ag or Pt (guest) were deposited on b-Fe 2 O 3 by means of Radio Frequency (RF)-sputtering under mild conditions (Ar plasmas; total pressure = 0.3 mbar; substrate temperature = 60 C; RF-power = 5 W). A thorough structural and morphological characterization performed on these systems highlighted the dispersion of NPs over the host oxide. To this regard, x-ray Photoelectron and x-ray Excited Auger Electron Spectroscopies (XPS and XE-AES) analyses provided valuable information on the system chemical composition, with special focus on NPs surface interaction with iron(III) oxide matrices. At variance with platinum, which retained its metallic state, an appreciable Ag surface oxidation was observed, an important issue in view of possible functional applications in photocatalysis and gas sensing.

International Journal of Hydrogen Energy, 2013

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2013

In this work, we report on a single-step Plasma Enhanced-Chemical Vapor Deposition (PE-CVD) process for the synthesis of iron(III) oxide based nanomaterials. A key feature of the adopted fabrication strategy is the use of a fluorinated Fe(II) b-diketonate diamine precursor, enabling a homogeneous Fe 2 O 3 in-situ doping and resulting in a tunable fluorine content as a function of deposition temperature. To this regard, a detailed study of the nature and amount of fluorinecontaining moieties is strongly required in view of the process optimization. Specifically, X-ray Photoelectron Spectroscopy (XPS) analysis represents a strategic tool to evaluate the system chemical composition, and also to evidence the presence of fluorine in different chemical states, such as lattice fluorine (F-Fe) and traces of precursor residuals (CF x ) at the system surface. In the present study, spectroscopic data are presented and discussed in detail for a representative Fe 2 O 3 specimen.

Thin Solid Films, 2008

This work concerns growth and characterization of iron oxide (mainly α-Fe 2 O 3 ) thin films with a non-toxic and easy to manipulate technique. The latter consists of spraying FeCl 3 ·6H 2 O (0.03 M)-based aqueous solution during 30 min onto glass substrates heated at 350°C with a spray flow of 5 ml/min. These conditions led to the formation of rust red amorphous films. Well crystallized Fe 2 O 3 films were obtained after annealing in vacuum-sealed tube (~10 − 4 Pa) for 5 h at different temperatures ranging from 250°C to 400°C. The structure of the crystallized films was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and microprobe analyses. Two phases corresponding to α-Fe 2 O 3 and Fe(OOH) were evidenced. The major phase was found to be related to the α-Fe 2 O 3 compound, which appears at low annealing temperature, while the best growth of the Fe(OOH) minor phase was obtained after annealing at about 350°C; beyond this temperature the Fe(OOH) minor phase tends to disappear and completely transforms into α-Fe 2 O 3 . The average crystallite size dimension of the α-Fe 2 O 3 phase, determined from XRD patterns, changes from 45 nm to 85 nm as the annealing temperature increases from 250°C to 400°C. SEM images show compact and granular films, while microprobe analyses show rather stoichiometric Fe 2 O 3 films at an annealing temperature of about 350°C. Optical analyses enabled to point out direct band-gap energy of about 2.1 eV.

Materials Chemistry and Physics, 2018

Iron oxide films were synthesized by pulsed-DC magnetron sputtering from a metallic target in Ar and O2 gas mixtures. Plasma emission monitoring was implemented to accurately control the metalto-oxygen ratio in the coating through the chemical state of the iron target. The intensity of the Fe* emission line was maintained at a given value (setpoint) in regulating the introduced oxygen flow rate. In addition, the oxidation rate of the growing film was adjusted by controlling the oxidationto-deposition rate ratio as a function of the position of the substrates relative to the magnetron axis. The iron oxide films were characterized by X-ray diffraction, UV-VIS spectrophotometry, electrical measurement and vibrating sample magnetometry. In addition to the crystallization of 2 pure hematite and magnetite phases, both phases coexist in a transition domain for a short range of setpoint depending on the oxidation-to-deposition rate ratio. The electrical, optical and magnetic behaviors of the FeOx films suggest that the relative proportion of phases can be tailored in this range. The FeOx film behaviors can then be tuned from the hematite semiconductor properties to the semi-metallic magnetite properties.

2013

The present work reports on the synthesis of fluorine doped Fe 2 O 3 nanomaterials by a single-step plasma enhanced-chemical vapor deposition (PE-CVD) strategy. In particular, Fe(hfa) 2 TMEDA (hfa ¼ 1,1,1,5,5,5hexafluoro-2,4-pentanedionate; TMEDA ¼ N,N,N 0 ,N 0-tetramethylethylenediamine) was used as molecular source for both Fe and F in Ar/O 2 plasmas. The structure, morphology and chemical composition of the synthesized nanosystems were thoroughly analyzed by two-dimensional X-ray diffraction (XRD 2), field emission-scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS) and transmission electron microscopy (TEM). A suitable choice of processing parameters enabled the selective formation of a-Fe 2 O 3 nanomaterials, characterized by an homogeneous F doping, even at 100 C. Interestingly, a simultaneous control of the system nanoscale organization and fluorine content could be achieved by varying the sole growth temperature. The tailored properties of the resulting materials can be favourably exploited for several technological applications, ranging from photocatalysis, to photoelectrochemical cells and gas sensing.

IOP conference series, 2013