國立虎尾科技大學 |

Microplasma Jet Synthesis of Ni-Fe Oxide Films for Magnetic Exchange Bias and Electrocatalytic Studies.

Record Type:	Language materials, manuscript : Monograph/item
Title/Author:	Microplasma Jet Synthesis of Ni-Fe Oxide Films for Magnetic Exchange Bias and Electrocatalytic Studies./
Author:	Pebley, Andrew Christian.
Description:	1 online resource (155 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 79-03, Section: B.
Contained By:	Dissertations Abstracts International79-03B.
Subject:	Chemical engineering. -
Online resource:	click for full text (PQDT)
ISBN:	9780355271331

Microplasma Jet Synthesis of Ni-Fe Oxide Films for Magnetic Exchange Bias and Electrocatalytic Studies.
Pebley, Andrew Christian.

Microplasma Jet Synthesis of Ni-Fe Oxide Films for Magnetic Exchange Bias and Electrocatalytic Studies. - 1 online resource (155 pages)

Source: Dissertations Abstracts International, Volume: 79-03, Section: B.

Thesis (Ph.D.)--University of California, Santa Barbara, 2017.

Includes bibliographical references

Ni-Fe oxides have received significant interest from the scientific community because they have attractive magnetic and electrochemical properties for use in next generation data storage and energy conversion technologies. For example, the NiFe2O4/NiO nanogranular system exhibits the exchange bias effect, a magnetic phenomenon occurring at the interface of a ferro- or ferrimagnet (FM or FiM) and an antiferromagnet (AFM), where the AFM acts to increase the magnetic hardness of the corresponding FM or FiM. Additionally, doping of NiO with Fe has resulted in remarkably high catalytic activities for water splitting, a potential clean energy alternative to fossil fuels. A key challenge in implementing these Ni-Fe oxides for magnetic and electrocatalytic applications is the ability to control film morphology, crystallinity, composition, chemical phase, and doping during synthesis. Moreover, how these physiochemical properties effect magnetic and electrochemical behavior in the Ni-Fe oxide system is not fully understood. This dissertation focuses on the development and use of a novel synthesis technique, known as microplasma (MP) jet-based deposition, for the fabrication of biphasic NiFe2O4 (FiM)/NiO (AFM) and Fe-doped NiO nanostructured films for fundamental studies of exchange bias and electrocatalysis, respectively. The goal of this work was to understand how MP operation and deposition conditions (e.g., precursor composition, flux, substrate temperature, and post-deposition heat treatment) influence Ni-Fe oxide growth and film microstructure. Specifically, the role of composition, phase fraction, grain size, temperature, and interfacial density on exchange bias phenomena in NiFe 2O4/NiO nanogranular films was investigated. MP jets were also used to realize metastable Fe-doped NiO films with high surface area to assess how doping affects the electrochemical properties of NiO for the oxygen evolution reaction (OER). Biphasic NiFe2O4/NiO films of different composition were synthesized using MP jets and post-deposition annealing. The exchange bias effect (HE) and enhanced coercivity (HC) were seen at 300 K, which was the first time that HE has been reported at room temperature in the NiFe2O4/NiO nanogranular system. These values increased with Ni incorporation, and were rationalized as due to increased NiFe2O4/NiO interfacial density. Moreover, MP jet deposition of NiFe2O4/NiO films on heated substrates was explored to realize higher interfacial densities. HE was observed at low temperatures in these films, but not at room temperature, which was attributed to spin glass coupling arising from structurally disordered interfaces. Through systematic post-deposition heat treatments, it was found that spin glass-like phases disappeared after annealing, and the observed HE was due to direct exchange coupling between the NiO and NiFe2O 4 phases. MP jets were also used to deposit high-surface area, metastable Fe-doped NiO films of different composition (up to 20% Fe on a metals basis) at room temperature on indium tin oxide (ITO) substrates for OER catalysis. It was seen that Fe fully incorporated into the NiO rocksalt lattice, decreasing the overpotential for OER (i.e., 360 to 310 mV at 10 mA/cm2 for NiO and Ni0.95Fe0.05O, respectively). Turnover frequency (TOF) calculations demonstrated an improvement in the catalytic activity of the NiO surface with Fe doping, and chronopotentiometry measurements verified that Fe-doped NiO films were mechanically and chemically robust during extended operation under OER conditions. Overall, this work demonstrates the potential of MP jet deposition as a versatile, one-step approach to realize multi-phase and doped nanostructured oxide films with high interfacial densities and surface areas for a variety of magnetic and energy conversion applications.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2024

Mode of access: World Wide Web

ISBN: 9780355271331Subjects--Topical Terms:

555952
Chemical engineering.
Subjects--Index Terms:

Exchange biasIndex Terms--Genre/Form:

554714
Electronic books.

Microplasma Jet Synthesis of Ni-Fe Oxide Films for Magnetic Exchange Bias and Electrocatalytic Studies.
LDR:05420ntm a22004337 4500 001 1151940
005 20241125080148.5
006 m o d
007 cr mn ---uuuuu
008 250605s2017 xx obm 000 0 eng d
020 $a 9780355271331
035 $a (MiAaPQ)AAI10599922
035 $a (MiAaPQ)ucsb:13462
035 $a AAI10599922
040 $a MiAaPQ $b eng $c MiAaPQ $d NTU
100 1 $a Pebley, Andrew Christian. $3 1478785
245 1 0 $a Microplasma Jet Synthesis of Ni-Fe Oxide Films for Magnetic Exchange Bias and Electrocatalytic Studies.
264 0 $c 2017
300 $a 1 online resource (155 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 79-03, Section: B.
500 $a Publisher info.: Dissertation/Thesis.
500 $a Advisor: Pollock, Tresa M.;Gordon, Michael J.
502 $a Thesis (Ph.D.)--University of California, Santa Barbara, 2017.
504 $a Includes bibliographical references
520 $a Ni-Fe oxides have received significant interest from the scientific community because they have attractive magnetic and electrochemical properties for use in next generation data storage and energy conversion technologies. For example, the NiFe2O4/NiO nanogranular system exhibits the exchange bias effect, a magnetic phenomenon occurring at the interface of a ferro- or ferrimagnet (FM or FiM) and an antiferromagnet (AFM), where the AFM acts to increase the magnetic hardness of the corresponding FM or FiM. Additionally, doping of NiO with Fe has resulted in remarkably high catalytic activities for water splitting, a potential clean energy alternative to fossil fuels. A key challenge in implementing these Ni-Fe oxides for magnetic and electrocatalytic applications is the ability to control film morphology, crystallinity, composition, chemical phase, and doping during synthesis. Moreover, how these physiochemical properties effect magnetic and electrochemical behavior in the Ni-Fe oxide system is not fully understood. This dissertation focuses on the development and use of a novel synthesis technique, known as microplasma (MP) jet-based deposition, for the fabrication of biphasic NiFe2O4 (FiM)/NiO (AFM) and Fe-doped NiO nanostructured films for fundamental studies of exchange bias and electrocatalysis, respectively. The goal of this work was to understand how MP operation and deposition conditions (e.g., precursor composition, flux, substrate temperature, and post-deposition heat treatment) influence Ni-Fe oxide growth and film microstructure. Specifically, the role of composition, phase fraction, grain size, temperature, and interfacial density on exchange bias phenomena in NiFe 2O4/NiO nanogranular films was investigated. MP jets were also used to realize metastable Fe-doped NiO films with high surface area to assess how doping affects the electrochemical properties of NiO for the oxygen evolution reaction (OER). Biphasic NiFe2O4/NiO films of different composition were synthesized using MP jets and post-deposition annealing. The exchange bias effect (HE) and enhanced coercivity (HC) were seen at 300 K, which was the first time that HE has been reported at room temperature in the NiFe2O4/NiO nanogranular system. These values increased with Ni incorporation, and were rationalized as due to increased NiFe2O4/NiO interfacial density. Moreover, MP jet deposition of NiFe2O4/NiO films on heated substrates was explored to realize higher interfacial densities. HE was observed at low temperatures in these films, but not at room temperature, which was attributed to spin glass coupling arising from structurally disordered interfaces. Through systematic post-deposition heat treatments, it was found that spin glass-like phases disappeared after annealing, and the observed HE was due to direct exchange coupling between the NiO and NiFe2O 4 phases. MP jets were also used to deposit high-surface area, metastable Fe-doped NiO films of different composition (up to 20% Fe on a metals basis) at room temperature on indium tin oxide (ITO) substrates for OER catalysis. It was seen that Fe fully incorporated into the NiO rocksalt lattice, decreasing the overpotential for OER (i.e., 360 to 310 mV at 10 mA/cm2 for NiO and Ni0.95Fe0.05O, respectively). Turnover frequency (TOF) calculations demonstrated an improvement in the catalytic activity of the NiO surface with Fe doping, and chronopotentiometry measurements verified that Fe-doped NiO films were mechanically and chemically robust during extended operation under OER conditions. Overall, this work demonstrates the potential of MP jet deposition as a versatile, one-step approach to realize multi-phase and doped nanostructured oxide films with high interfacial densities and surface areas for a variety of magnetic and energy conversion applications.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2024
538 $a Mode of access: World Wide Web
650 4 $a Chemical engineering. $3 555952
650 4 $a Plasma physics. $2 bicssc $3 1030958
650 4 $a Materials science. $3 557839
653 $a Exchange bias
653 $a Microplasma
653 $a Nanoscale materials
653 $a Oxygen evolution catalysis
653 $a Thin film characterization
653 $a Thin film deposition
655 7 $a Electronic books. $2 local $3 554714
690 $a 0542
690 $a 0759
690 $a 0794
710 2 $a ProQuest Information and Learning Co. $3 1178819
710 2 $a University of California, Santa Barbara. $b Materials. $3 1187227
773 0 $t Dissertations Abstracts International $g 79-03B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=10599922 $z click for full text (PQDT)