Luận văn thạc sĩ synthesis and gas adsorption properties of nickel ferrite nanoparticles

different, armeating temperature co- igure 3.5, SEM image and size distribution figwe of C - NFO sample...40 Figure 3.6.. The response and recover time ol’ H — NFO coated sensor al diffe

TIANOI UNIVERSITY OF SCIENCE AND TECIINOLOGY

MASTER THESIS

Synthesis and gas adsorption properties of

nickel ferrite nanoparticles

CAO XUAN TRUONG

Truong CX211148M@isis hust edu vn

SOCTALIST REPUBLIC OF VIETNAM

Tndependenee — Freedom — Happiness

CONFIRMATION OF MASTER’S THESIS ADJUSTMENT

Full name of the author : Cav Xuan Fruong

Thesis topic: Synthesis and gas adsorption properties of nickel ferrite nanoparticles

Major: Material Science

Student ID: 20211148M

The author, the supervisor, and the Committee confirmed that the

author has adjusted and implemented the thesis according to the report of the

Committee on April 28", 2023 with the following contents:

- Literature review outline and content

- Spelling and printing errors

Day Month Year

Assoc, Prof, Nguyen Van Quy Cao Xuan Truong

COMMITTEE'S CHAIRMAN

Prof Nguyen Phuc Duong

Abstract

Industrialization and modemization in today society bring about many

benefits Pollution caused by these processes put people’s health and environmental status at risk It is urgent that a sensor with high sensitivity, stable

operalion, low cost, low energy consumption and mobility is developed lo

monitor the pollution status and prevent potential risk A quartz crystal microbalance (QCM) sensor is researched to meet those requirements This sensor can detect a small concentration of gas by mass change principle ‘To

enhance the adsorption capabilities, metal oxides are deposited on the electrode

of QCM sensor Among the most considerable sensing materials, NiTe:Ox nanoparticles with porous structure, large specific area and various functioning group on its surface can be considered suitable for being a good sensing layer of

QCM sensor The material is fabricated by hydrothermal and co-precipitation

methods The characterization of NiFe:Oa was investigated by some measuring anethods ‘then the QCM sensors are coated and tested their gas sensing ability

by OCM200 system Aller various experiments, il can be assured thal a QCM

coated NiFe2Q1 sensor is capable of detecting SO2, NOz, IbS at room

temperature In addition, the results suggest that the material are most responsive

to SO» and little deviated after a long time operating The mechanism of physisorption of nickel ferrites 18 also presented

STUDENT

Cao Xuan ‘Truong

Figure 3.1, XRD spectra of NiFez04 al different, armeating temperature (co-

igure 3.5, SEM image and size distribution figwe of C - NFO sample 40 Figure 3.6 SEM image and size distribution figure of H - NFO sample 40 Figure 3.7 ‘The Fourier transform infrared spectrum of C NEO (a) and H

Figure 3.8 Adsorption and desorption isotherm and pore size distribution of C -

Figure 3.9 Gas mass absorbed on the QCM-C - NEO and QCM-H— NEO 44 Figure 3.10 The relationships betweeu the frequency shifis/adsorbed mass on the QCM C - NFO electrode and target gases concentrations from 5 to 20 ppm of

concentrations between 5ppm and 20ppm of two sensors - - a7

Figure 3.13 The comparison between SƠ; and NOs sensibility of both sensors

« HH0 48 Figure 3.14 The long -term stability « oŸ gas adsorption performanee 48

igure 3.15 ‘Ihe response and recover time of C NEO coated sensor at diTerent coneontration of 8O (a) and NÓ (b) M

Figure 3.16 The response and recover time ol’ H — NFO coated sensor al different concentration of SO2 (a) and NO» (b) coe 51 Figure 3.17 Response towards different gases in different concentrations of C - bì) m ố _—- Figure 3.18 Response towards different gases in different concentrations of H - NEO sample 53

Figure 3.1, XRD spectra of NiFez04 al different, armeating temperature (co-

igure 3.5, SEM image and size distribution figwe of C - NFO sample 40 Figure 3.6 SEM image and size distribution figure of H - NFO sample 40 Figure 3.7 ‘The Fourier transform infrared spectrum of C NEO (a) and H

Figure 3.8 Adsorption and desorption isotherm and pore size distribution of C -

Figure 3.9 Gas mass absorbed on the QCM-C - NEO and QCM-H— NEO 44 Figure 3.10 The relationships betweeu the frequency shifis/adsorbed mass on the QCM C - NFO electrode and target gases concentrations from 5 to 20 ppm of

concentrations between 5ppm and 20ppm of two sensors - - a7

Figure 3.13 The comparison between SƠ; and NOs sensibility of both sensors

« HH0 48 Figure 3.14 The long -term stability « oŸ gas adsorption performanee 48

igure 3.15 ‘Ihe response and recover time of C NEO coated sensor at diTerent coneontration of 8O (a) and NÓ (b) M

Figure 3.16 The response and recover time ol’ H — NFO coated sensor al different concentration of SO2 (a) and NO» (b) coe 51 Figure 3.17 Response towards different gases in different concentrations of C - bì) m ố _—- Figure 3.18 Response towards different gases in different concentrations of H - NEO sample 53

ABBREVIATIONS

BET Đrunauer — Finmell — Teller

BH Barrett — Joyner —Halenda

TTR Fourier Transform Infrared Spectroscopy

ICPDS Joint Committee on Powder Diffraction Standards

ITIMS International Training Institute for Materials Science

MFC Masa Flow Controller

NPs Nano particles

ppm Parts per million

QCM Quartz Crystal Microbalance

sccm Standard cubic centimeters per minute

SEM Scanning Electron Microscopy

TEM Transmission Electron Microscope

ABBREVIATIONS

BET Đrunauer — Finmell — Teller

BH Barrett — Joyner —Halenda

TTR Fourier Transform Infrared Spectroscopy

ICPDS Joint Committee on Powder Diffraction Standards

ITIMS International Training Institute for Materials Science

MFC Masa Flow Controller

NPs Nano particles

ppm Parts per million

QCM Quartz Crystal Microbalance

sccm Standard cubic centimeters per minute

SEM Scanning Electron Microscopy

TEM Transmission Electron Microscope

LIST OF FIGURES Figure 1.1 Schematic of a partial unit cell and ferrimagnetic ordering, of spinel ferrite structure [44] TH HH ga ses 14

igure 12 Cation distribution in spinel femites (a) inverted ferrites, ) mumganese ferrites and (¢) zine manganese ferziles [18] - 15

Figure 1.3 Atomic positions in the inverse spinel structure of NFO A portion of connecting (Fe,Ni)Os octahedra around a Fe, tetrahedron is alsa depicted, where “Oc” and “Te” in the suffix indicate the octahedron and tetrahedron 17 Figure 1.4 Typical device in hydrothermal method 18 Figure 1.5 The piezoelectric effect in the material: without piezoelectric polarization (A), the molecules subjected to an external force with charge forming (B), and piczoclectrie cffect on the surface Note that, P denotes

polarization vector, F is applied external force [36] 19

Figure 1.6 Direct and inverse pievoelecinic effect in the material 20

Figure 1.7 Practical application of the piezoelectric material [34] 20

Figure 1.8 The schematic of quartz crystal with clectrode (ab), the strain induced in an AT cut crystal on application of AC! voltage (c), and the amphinde

of vibration varies with the distance from the center of the sehSOI "-

#igure 1%, ‘The quartz crystal structure (A), A'l-cut crystal (3), and “aystal

Tigure LIU The Butterworth-Van Dyke (BVD) equivalent circuit for an unloaded quartz crystal microbalance, QCM under viscous and mass loading (A),

and Ihe device parameter versus frequeticy characlerislic curve (B) [45] 23

Figure 1.11 The diagram of Quartz Crystal Microbalance oscillator 24

Figure 1.13 (a) Schematic top view and cross-sectional view of 2 QCM uncoated and coated with a sensing layer, and (b) the illustration of Frequency decreasing

due to active layer coating and during sensing measurements [50] « vee 26 Figure 2.1 NiFexO« NPs hydrothermal method synthesis process 29 Figure 2.2 Nilfez©a NES cơ precipiiation synthesis proG€SS co co 2Ø Figure 2.3 XRD measurement system in ITIMS - 30 Figure 2.4 Working principle of scanning electron microscopy 160] 31 Figure 2.5 General layout of a TEM - 32

Figure 2.6 (a) Schematic diagram of a Fourier transform infrared instrument (b)

Figure 2.7 Spray coating system and spraving "`" sueesseusoou 35 igure 2.8 Sehematic diagram of gas measuring system Xueesseusoou 35 igurc 2.9 Gas measuring syse c onooirriieiroree sao 3Ó

3.3 Gas sensing properties of QUM coated NiHesOa NEs sao 43

3.3.1 Mass density of NiFeaOx NEs đeposited on the elecưode 43

3.3.2 Inorganic toxic gases adsorption ability - 43 3.3.3 Long-temstability .49

3.3 Gas sensing properties of QUM coated NiHesOa NEs sao 43

3.3.1 Mass density of NiFeaOx NEs đeposited on the elecưode 43

3.3.2 Inorganic toxic gases adsorption ability - 43 3.3.3 Long-temstability .49

Figure 3.1, XRD spectra of NiFez04 al different, armeating temperature (co-

igure 3.5, SEM image and size distribution figwe of C - NFO sample 40 Figure 3.6 SEM image and size distribution figure of H - NFO sample 40 Figure 3.7 ‘The Fourier transform infrared spectrum of C NEO (a) and H

Figure 3.8 Adsorption and desorption isotherm and pore size distribution of C -

Figure 3.9 Gas mass absorbed on the QCM-C - NEO and QCM-H— NEO 44 Figure 3.10 The relationships betweeu the frequency shifis/adsorbed mass on the QCM C - NFO electrode and target gases concentrations from 5 to 20 ppm of

concentrations between 5ppm and 20ppm of two sensors - - a7

Figure 3.13 The comparison between SƠ; and NOs sensibility of both sensors

« HH0 48 Figure 3.14 The long -term stability « oŸ gas adsorption performanee 48

igure 3.15 ‘Ihe response and recover time of C NEO coated sensor at diTerent coneontration of 8O (a) and NÓ (b) M

Figure 3.16 The response and recover time ol’ H — NFO coated sensor al different concentration of SO2 (a) and NO» (b) coe 51 Figure 3.17 Response towards different gases in different concentrations of C - bì) m ố _—- Figure 3.18 Response towards different gases in different concentrations of H - NEO sample 53

INTRODUCTION

CHAPTER 1 LITERATURE REVIEW

1.1 Introduction of nickel ferrite (NiFexO,) 14 1.1.1 Overview of the structure of fermites - 14 1.1.2 0 Nickel Ferrite (NiFa2O4)} - - - 16

1.13 Fabrication methods - - H 1.2 Introduction of quartz crystal microbalance (QCM) - 18

121 Piezoelectric Effect - - - 18

1.2.2 — Quartzcrystalmierobalanee "—

1.3 Quartzcrystal microbalance gas sehsor 24

1.31 IntreducHon of QCM gas sensor c seo 214 1.3.2 QƠMsenmsor working prinoiple "—-

CHAPTER 2 EXPERIMENT DETAILS

2.1 Chomical and apparatus

214 Chemical - - 28

2.1.2 Apparatus - - 28

2.2 NiFe2O« nanoparticles fabrication - 28

2.21 Nilfe.O nanoparticles fabrication by hydrothermal method .28

2.2.2 NH'e:Ox nanoparticlas fabrication by co-precipitation method 29 2.3 Characterizatienmethods —-

X-ray Diffaction (XRĐ) ec "¬

.30 31 Scanning Electron Microscope ‘Transmission electron microscope Fourier Transform Initared Spectroscopy (FTTR) Surface area and pore size distribulion measurements 33 2.4 Fabrication of NiFexO4 sensing layer on the QCM electrode and gas

2.4.1 Pebricatien ofNiFe:Oa sensing layer ơn QCM 34 2.4.2 Gas scnsing measureiieii e si 135

CHAPTER 3 RESULTS AND DISCUSSIO!

3.1 Fabrication method iwestigation "—- ST

Figure 3.1, XRD spectra of NiFez04 al different, armeating temperature (co-

igure 3.5, SEM image and size distribution figwe of C - NFO sample 40 Figure 3.6 SEM image and size distribution figure of H - NFO sample 40 Figure 3.7 ‘The Fourier transform infrared spectrum of C NEO (a) and H

Figure 3.8 Adsorption and desorption isotherm and pore size distribution of C -

Figure 3.9 Gas mass absorbed on the QCM-C - NEO and QCM-H— NEO 44 Figure 3.10 The relationships betweeu the frequency shifis/adsorbed mass on the QCM C - NFO electrode and target gases concentrations from 5 to 20 ppm of

concentrations between 5ppm and 20ppm of two sensors - - a7

Figure 3.13 The comparison between SƠ; and NOs sensibility of both sensors

« HH0 48 Figure 3.14 The long -term stability « oŸ gas adsorption performanee 48

igure 3.15 ‘Ihe response and recover time of C NEO coated sensor at diTerent coneontration of 8O (a) and NÓ (b) M

Figure 3.16 The response and recover time ol’ H — NFO coated sensor al different concentration of SO2 (a) and NO» (b) coe 51 Figure 3.17 Response towards different gases in different concentrations of C - bì) m ố _—- Figure 3.18 Response towards different gases in different concentrations of H - NEO sample 53

ABBREVIATIONS

BET Đrunauer — Finmell — Teller

BH Barrett — Joyner —Halenda

TTR Fourier Transform Infrared Spectroscopy

ICPDS Joint Committee on Powder Diffraction Standards

ITIMS International Training Institute for Materials Science

MFC Masa Flow Controller

NPs Nano particles

ppm Parts per million

QCM Quartz Crystal Microbalance

sccm Standard cubic centimeters per minute

SEM Scanning Electron Microscopy

TEM Transmission Electron Microscope

INTRODUCTION

CHAPTER 1 LITERATURE REVIEW

1.1 Introduction of nickel ferrite (NiFexO,) 14 1.1.1 Overview of the structure of fermites - 14 1.1.2 0 Nickel Ferrite (NiFa2O4)} - - - 16

1.13 Fabrication methods - - H 1.2 Introduction of quartz crystal microbalance (QCM) - 18

121 Piezoelectric Effect - - - 18

1.2.2 — Quartzcrystalmierobalanee "—

1.3 Quartzcrystal microbalance gas sehsor 24

1.31 IntreducHon of QCM gas sensor c seo 214 1.3.2 QƠMsenmsor working prinoiple "—-

CHAPTER 2 EXPERIMENT DETAILS

2.1 Chomical and apparatus

214 Chemical - - 28

2.1.2 Apparatus - - 28

2.2 NiFe2O« nanoparticles fabrication - 28

2.21 Nilfe.O nanoparticles fabrication by hydrothermal method .28

2.2.2 NH'e:Ox nanoparticlas fabrication by co-precipitation method 29 2.3 Characterizatienmethods —-

X-ray Diffaction (XRĐ) ec "¬

.30 31 Scanning Electron Microscope ‘Transmission electron microscope Fourier Transform Initared Spectroscopy (FTTR) Surface area and pore size distribulion measurements 33 2.4 Fabrication of NiFexO4 sensing layer on the QCM electrode and gas

2.4.1 Pebricatien ofNiFe:Oa sensing layer ơn QCM 34 2.4.2 Gas scnsing measureiieii e si 135

CHAPTER 3 RESULTS AND DISCUSSIO!

3.1 Fabrication method iwestigation "—- ST

Acknowledgement First of all, 1 would like to express my greatest gratitude toward my supervisor, Assoc Prof Nguyen Van Quy ty lor being wm ideal (cacher, mentor, and

thesis supervisor, offering advice and encouragement with a perfect blend of

insight and humor I also desire ta extend my appreciation to Dr Luong Ngoc Anh, Dr Nguyen ‘Thanh Vinh and Dr ‘iran Van Dang for their invaluable

recommendations ard explanations related to my research topic

I would also like to express my special thanks to all lecturers and

employees at TTTMs for creating a wonderful environment while T was on my

course | also thank the project grant number 132021-3KA-04

Sincerely, I would like to thank my lab-mates at Room 202 for their

strong support, endless assistance, regular encouragement and inspirations every

single day

Tast bul niol least, my special gralilude is expressed la my doar family

members, who are always by my side, both fiancial and mental supporlive

during my master program.

ABBREVIATIONS

BET Đrunauer — Finmell — Teller

BH Barrett — Joyner —Halenda

TTR Fourier Transform Infrared Spectroscopy

ICPDS Joint Committee on Powder Diffraction Standards

ITIMS International Training Institute for Materials Science

MFC Masa Flow Controller

NPs Nano particles

ppm Parts per million

QCM Quartz Crystal Microbalance

sccm Standard cubic centimeters per minute

SEM Scanning Electron Microscopy

TEM Transmission Electron Microscope

Acknowledgement First of all, 1 would like to express my greatest gratitude toward my supervisor, Assoc Prof Nguyen Van Quy ty lor being wm ideal (cacher, mentor, and

thesis supervisor, offering advice and encouragement with a perfect blend of

insight and humor I also desire ta extend my appreciation to Dr Luong Ngoc Anh, Dr Nguyen ‘Thanh Vinh and Dr ‘iran Van Dang for their invaluable

recommendations ard explanations related to my research topic

I would also like to express my special thanks to all lecturers and

employees at TTTMs for creating a wonderful environment while T was on my

course | also thank the project grant number 132021-3KA-04

Sincerely, I would like to thank my lab-mates at Room 202 for their

strong support, endless assistance, regular encouragement and inspirations every

single day

Tast bul niol least, my special gralilude is expressed la my doar family

members, who are always by my side, both fiancial and mental supporlive

during my master program.

Abstract

Industrialization and modemization in today society bring about many

benefits Pollution caused by these processes put people’s health and environmental status at risk It is urgent that a sensor with high sensitivity, stable

operalion, low cost, low energy consumption and mobility is developed lo

monitor the pollution status and prevent potential risk A quartz crystal microbalance (QCM) sensor is researched to meet those requirements This sensor can detect a small concentration of gas by mass change principle ‘To

enhance the adsorption capabilities, metal oxides are deposited on the electrode

of QCM sensor Among the most considerable sensing materials, NiTe:Ox nanoparticles with porous structure, large specific area and various functioning group on its surface can be considered suitable for being a good sensing layer of

QCM sensor The material is fabricated by hydrothermal and co-precipitation

methods The characterization of NiFe:Oa was investigated by some measuring anethods ‘then the QCM sensors are coated and tested their gas sensing ability

by OCM200 system Aller various experiments, il can be assured thal a QCM

coated NiFe2Q1 sensor is capable of detecting SO2, NOz, IbS at room

temperature In addition, the results suggest that the material are most responsive

to SO» and little deviated after a long time operating The mechanism of physisorption of nickel ferrites 18 also presented

STUDENT

Cao Xuan ‘Truong

3.3 Gas sensing properties of QUM coated NiHesOa NEs sao 43

3.3.1 Mass density of NiFeaOx NEs đeposited on the elecưode 43

3.3.2 Inorganic toxic gases adsorption ability - 43 3.3.3 Long-temstability .49

Figure 3.1, XRD spectra of NiFez04 al different, armeating temperature (co-

igure 3.5, SEM image and size distribution figwe of C - NFO sample 40 Figure 3.6 SEM image and size distribution figure of H - NFO sample 40 Figure 3.7 ‘The Fourier transform infrared spectrum of C NEO (a) and H

Figure 3.8 Adsorption and desorption isotherm and pore size distribution of C -

Figure 3.9 Gas mass absorbed on the QCM-C - NEO and QCM-H— NEO 44 Figure 3.10 The relationships betweeu the frequency shifis/adsorbed mass on the QCM C - NFO electrode and target gases concentrations from 5 to 20 ppm of

concentrations between 5ppm and 20ppm of two sensors - - a7

Figure 3.13 The comparison between SƠ; and NOs sensibility of both sensors

« HH0 48 Figure 3.14 The long -term stability « oŸ gas adsorption performanee 48

igure 3.15 ‘Ihe response and recover time of C NEO coated sensor at diTerent coneontration of 8O (a) and NÓ (b) M

Figure 3.16 The response and recover time ol’ H — NFO coated sensor al different concentration of SO2 (a) and NO» (b) coe 51 Figure 3.17 Response towards different gases in different concentrations of C - bì) m ố _—- Figure 3.18 Response towards different gases in different concentrations of H - NEO sample 53

Figure 3.1, XRD spectra of NiFez04 al different, armeating temperature (co-

igure 3.5, SEM image and size distribution figwe of C - NFO sample 40 Figure 3.6 SEM image and size distribution figure of H - NFO sample 40 Figure 3.7 ‘The Fourier transform infrared spectrum of C NEO (a) and H

Figure 3.8 Adsorption and desorption isotherm and pore size distribution of C -

Figure 3.9 Gas mass absorbed on the QCM-C - NEO and QCM-H— NEO 44 Figure 3.10 The relationships betweeu the frequency shifis/adsorbed mass on the QCM C - NFO electrode and target gases concentrations from 5 to 20 ppm of

concentrations between 5ppm and 20ppm of two sensors - - a7

Figure 3.13 The comparison between SƠ; and NOs sensibility of both sensors

« HH0 48 Figure 3.14 The long -term stability « oŸ gas adsorption performanee 48

igure 3.15 ‘Ihe response and recover time of C NEO coated sensor at diTerent coneontration of 8O (a) and NÓ (b) M

Figure 3.16 The response and recover time ol’ H — NFO coated sensor al different concentration of SO2 (a) and NO» (b) coe 51 Figure 3.17 Response towards different gases in different concentrations of C - bì) m ố _—- Figure 3.18 Response towards different gases in different concentrations of H - NEO sample 53

INTRODUCTION

1.1 Introduction of nickel ferrite (NiFexO,) 14

1.1.1 Overview of the structure of fermites - 14

1.2 Introduction of quartz crystal microbalance (QCM) - 18

1.2.2 — Quartzcrystalmierobalanee "— 1.3 Quartzcrystal microbalance gas sehsor 24

1.31 IntreducHon of QCM gas sensor c seo 214

1.3.2 QƠMsenmsor working prinoiple "—-

CHAPTER 2 EXPERIMENT DETAILS

2.2 NiFe2O« nanoparticles fabrication - 28

2.21 Nilfe.O nanoparticles fabrication by hydrothermal method .28

2.2.2 NH'e:Ox nanoparticlas fabrication by co-precipitation method 29

2.3 Characterizatienmethods —-

X-ray Diffaction (XRĐ) ec "¬

.30 31

Surface area and pore size distribulion measurements 33

2.4 Fabrication of NiFexO4 sensing layer on the QCM electrode and gas

2.4.1 Pebricatien ofNiFe:Oa sensing layer ơn QCM 34 2.4.2 Gas scnsing measureiieii e si 135

CHAPTER 3 RESULTS AND DISCUSSIO!

3.1 Fabrication method iwestigation "—- ST

INTRODUCTION

1.1 Introduction of nickel ferrite (NiFexO,) 14

1.1.1 Overview of the structure of fermites - 14

1.2 Introduction of quartz crystal microbalance (QCM) - 18

1.2.2 — Quartzcrystalmierobalanee "— 1.3 Quartzcrystal microbalance gas sehsor 24

1.31 IntreducHon of QCM gas sensor c seo 214

1.3.2 QƠMsenmsor working prinoiple "—-

CHAPTER 2 EXPERIMENT DETAILS

2.2 NiFe2O« nanoparticles fabrication - 28

2.21 Nilfe.O nanoparticles fabrication by hydrothermal method .28

2.2.2 NH'e:Ox nanoparticlas fabrication by co-precipitation method 29

2.3 Characterizatienmethods —-

X-ray Diffaction (XRĐ) ec "¬

.30 31

Surface area and pore size distribulion measurements 33

2.4 Fabrication of NiFexO4 sensing layer on the QCM electrode and gas

2.4.1 Pebricatien ofNiFe:Oa sensing layer ơn QCM 34 2.4.2 Gas scnsing measureiieii e si 135

CHAPTER 3 RESULTS AND DISCUSSIO!

3.1 Fabrication method iwestigation "—- ST

3.3 Gas sensing properties of QUM coated NiHesOa NEs sao 43

3.3.1 Mass density of NiFeaOx NEs đeposited on the elecưode 43

3.3.2 Inorganic toxic gases adsorption ability - 43 3.3.3 Long-temstability .49

Acknowledgement First of all, 1 would like to express my greatest gratitude toward my supervisor, Assoc Prof Nguyen Van Quy ty lor being wm ideal (cacher, mentor, and

thesis supervisor, offering advice and encouragement with a perfect blend of

insight and humor I also desire ta extend my appreciation to Dr Luong Ngoc Anh, Dr Nguyen ‘Thanh Vinh and Dr ‘iran Van Dang for their invaluable

recommendations ard explanations related to my research topic

I would also like to express my special thanks to all lecturers and

employees at TTTMs for creating a wonderful environment while T was on my

course | also thank the project grant number 132021-3KA-04

Sincerely, I would like to thank my lab-mates at Room 202 for their

strong support, endless assistance, regular encouragement and inspirations every

single day

Tast bul niol least, my special gralilude is expressed la my doar family

members, who are always by my side, both fiancial and mental supporlive

during my master program.

ABBREVIATIONS

BET Đrunauer — Finmell — Teller

BH Barrett — Joyner —Halenda

TTR Fourier Transform Infrared Spectroscopy

ICPDS Joint Committee on Powder Diffraction Standards

ITIMS International Training Institute for Materials Science

MFC Masa Flow Controller

NPs Nano particles

ppm Parts per million

QCM Quartz Crystal Microbalance

sccm Standard cubic centimeters per minute

SEM Scanning Electron Microscopy

TEM Transmission Electron Microscope

LIST OF FIGURES Figure 1.1 Schematic of a partial unit cell and ferrimagnetic ordering, of spinel ferrite structure [44] TH HH ga ses 14

igure 12 Cation distribution in spinel femites (a) inverted ferrites, ) mumganese ferrites and (¢) zine manganese ferziles [18] - 15

Figure 1.3 Atomic positions in the inverse spinel structure of NFO A portion of connecting (Fe,Ni)Os octahedra around a Fe, tetrahedron is alsa depicted, where “Oc” and “Te” in the suffix indicate the octahedron and tetrahedron 17 Figure 1.4 Typical device in hydrothermal method 18 Figure 1.5 The piezoelectric effect in the material: without piezoelectric polarization (A), the molecules subjected to an external force with charge forming (B), and piczoclectrie cffect on the surface Note that, P denotes

polarization vector, F is applied external force [36] 19

Figure 1.6 Direct and inverse pievoelecinic effect in the material 20

Figure 1.7 Practical application of the piezoelectric material [34] 20

Figure 1.8 The schematic of quartz crystal with clectrode (ab), the strain induced in an AT cut crystal on application of AC! voltage (c), and the amphinde

of vibration varies with the distance from the center of the sehSOI "-

#igure 1%, ‘The quartz crystal structure (A), A'l-cut crystal (3), and “aystal

Tigure LIU The Butterworth-Van Dyke (BVD) equivalent circuit for an unloaded quartz crystal microbalance, QCM under viscous and mass loading (A),

and Ihe device parameter versus frequeticy characlerislic curve (B) [45] 23

Figure 1.11 The diagram of Quartz Crystal Microbalance oscillator 24

Figure 1.13 (a) Schematic top view and cross-sectional view of 2 QCM uncoated and coated with a sensing layer, and (b) the illustration of Frequency decreasing

due to active layer coating and during sensing measurements [50] « vee 26 Figure 2.1 NiFexO« NPs hydrothermal method synthesis process 29 Figure 2.2 Nilfez©a NES cơ precipiiation synthesis proG€SS co co 2Ø Figure 2.3 XRD measurement system in ITIMS - 30 Figure 2.4 Working principle of scanning electron microscopy 160] 31 Figure 2.5 General layout of a TEM - 32

Figure 2.6 (a) Schematic diagram of a Fourier transform infrared instrument (b)

Figure 2.7 Spray coating system and spraving "`" sueesseusoou 35 igure 2.8 Sehematic diagram of gas measuring system Xueesseusoou 35 igurc 2.9 Gas measuring syse c onooirriieiroree sao 3Ó

ABBREVIATIONS

BET Đrunauer — Finmell — Teller

BH Barrett — Joyner —Halenda

TTR Fourier Transform Infrared Spectroscopy

ICPDS Joint Committee on Powder Diffraction Standards

ITIMS International Training Institute for Materials Science

MFC Masa Flow Controller

NPs Nano particles

ppm Parts per million

QCM Quartz Crystal Microbalance

sccm Standard cubic centimeters per minute

SEM Scanning Electron Microscopy

TEM Transmission Electron Microscope

Figure 3.1, XRD spectra of NiFez04 al different, armeating temperature (co-

igure 3.5, SEM image and size distribution figwe of C - NFO sample 40 Figure 3.6 SEM image and size distribution figure of H - NFO sample 40 Figure 3.7 ‘The Fourier transform infrared spectrum of C NEO (a) and H

Figure 3.8 Adsorption and desorption isotherm and pore size distribution of C -

Figure 3.9 Gas mass absorbed on the QCM-C - NEO and QCM-H— NEO 44 Figure 3.10 The relationships betweeu the frequency shifis/adsorbed mass on the QCM C - NFO electrode and target gases concentrations from 5 to 20 ppm of

concentrations between 5ppm and 20ppm of two sensors - - a7

Figure 3.13 The comparison between SƠ; and NOs sensibility of both sensors

« HH0 48 Figure 3.14 The long -term stability « oŸ gas adsorption performanee 48

igure 3.15 ‘Ihe response and recover time of C NEO coated sensor at diTerent coneontration of 8O (a) and NÓ (b) M

Figure 3.16 The response and recover time ol’ H — NFO coated sensor al different concentration of SO2 (a) and NO» (b) coe 51 Figure 3.17 Response towards different gases in different concentrations of C - bì) m ố _—- Figure 3.18 Response towards different gases in different concentrations of H - NEO sample 53

Abstract

Industrialization and modemization in today society bring about many

benefits Pollution caused by these processes put people’s health and environmental status at risk It is urgent that a sensor with high sensitivity, stable

operalion, low cost, low energy consumption and mobility is developed lo

monitor the pollution status and prevent potential risk A quartz crystal microbalance (QCM) sensor is researched to meet those requirements This sensor can detect a small concentration of gas by mass change principle ‘To

enhance the adsorption capabilities, metal oxides are deposited on the electrode

of QCM sensor Among the most considerable sensing materials, NiTe:Ox nanoparticles with porous structure, large specific area and various functioning group on its surface can be considered suitable for being a good sensing layer of

QCM sensor The material is fabricated by hydrothermal and co-precipitation

methods The characterization of NiFe:Oa was investigated by some measuring anethods ‘then the QCM sensors are coated and tested their gas sensing ability

by OCM200 system Aller various experiments, il can be assured thal a QCM

coated NiFe2Q1 sensor is capable of detecting SO2, NOz, IbS at room

temperature In addition, the results suggest that the material are most responsive

to SO» and little deviated after a long time operating The mechanism of physisorption of nickel ferrites 18 also presented

STUDENT

Cao Xuan ‘Truong

3.3 Gas sensing properties of QUM coated NiHesOa NEs sao 43

3.3.1 Mass density of NiFeaOx NEs đeposited on the elecưode 43

3.3.2 Inorganic toxic gases adsorption ability - 43 3.3.3 Long-temstability .49

ABBREVIATIONS

BET Đrunauer — Finmell — Teller

BH Barrett — Joyner —Halenda

TTR Fourier Transform Infrared Spectroscopy

ICPDS Joint Committee on Powder Diffraction Standards

ITIMS International Training Institute for Materials Science

MFC Masa Flow Controller

NPs Nano particles

ppm Parts per million

QCM Quartz Crystal Microbalance

sccm Standard cubic centimeters per minute

SEM Scanning Electron Microscopy

TEM Transmission Electron Microscope

LIST OF FIGURES Figure 1.1 Schematic of a partial unit cell and ferrimagnetic ordering, of spinel ferrite structure [44] TH HH ga ses 14

igure 12 Cation distribution in spinel femites (a) inverted ferrites, ) mumganese ferrites and (¢) zine manganese ferziles [18] - 15

Figure 1.3 Atomic positions in the inverse spinel structure of NFO A portion of connecting (Fe,Ni)Os octahedra around a Fe, tetrahedron is alsa depicted, where “Oc” and “Te” in the suffix indicate the octahedron and tetrahedron 17 Figure 1.4 Typical device in hydrothermal method 18 Figure 1.5 The piezoelectric effect in the material: without piezoelectric polarization (A), the molecules subjected to an external force with charge forming (B), and piczoclectrie cffect on the surface Note that, P denotes

polarization vector, F is applied external force [36] 19

Figure 1.6 Direct and inverse pievoelecinic effect in the material 20

Figure 1.7 Practical application of the piezoelectric material [34] 20

Figure 1.8 The schematic of quartz crystal with clectrode (ab), the strain induced in an AT cut crystal on application of AC! voltage (c), and the amphinde

of vibration varies with the distance from the center of the sehSOI "-

#igure 1%, ‘The quartz crystal structure (A), A'l-cut crystal (3), and “aystal

Tigure LIU The Butterworth-Van Dyke (BVD) equivalent circuit for an unloaded quartz crystal microbalance, QCM under viscous and mass loading (A),

and Ihe device parameter versus frequeticy characlerislic curve (B) [45] 23

Figure 1.11 The diagram of Quartz Crystal Microbalance oscillator 24

Figure 1.13 (a) Schematic top view and cross-sectional view of 2 QCM uncoated and coated with a sensing layer, and (b) the illustration of Frequency decreasing

due to active layer coating and during sensing measurements [50] « vee 26 Figure 2.1 NiFexO« NPs hydrothermal method synthesis process 29 Figure 2.2 Nilfez©a NES cơ precipiiation synthesis proG€SS co co 2Ø Figure 2.3 XRD measurement system in ITIMS - 30 Figure 2.4 Working principle of scanning electron microscopy 160] 31 Figure 2.5 General layout of a TEM - 32

Figure 2.6 (a) Schematic diagram of a Fourier transform infrared instrument (b)

Figure 2.7 Spray coating system and spraving "`" sueesseusoou 35 igure 2.8 Sehematic diagram of gas measuring system Xueesseusoou 35 igurc 2.9 Gas measuring syse c onooirriieiroree sao 3Ó

INTRODUCTION

1.1 Introduction of nickel ferrite (NiFexO,) 14

1.1.1 Overview of the structure of fermites - 14

1.2 Introduction of quartz crystal microbalance (QCM) - 18

1.2.2 — Quartzcrystalmierobalanee "— 1.3 Quartzcrystal microbalance gas sehsor 24

1.31 IntreducHon of QCM gas sensor c seo 214

1.3.2 QƠMsenmsor working prinoiple "—-

CHAPTER 2 EXPERIMENT DETAILS

2.2 NiFe2O« nanoparticles fabrication - 28

2.21 Nilfe.O nanoparticles fabrication by hydrothermal method .28

2.2.2 NH'e:Ox nanoparticlas fabrication by co-precipitation method 29

2.3 Characterizatienmethods —-

X-ray Diffaction (XRĐ) ec "¬

.30 31

Surface area and pore size distribulion measurements 33

2.4 Fabrication of NiFexO4 sensing layer on the QCM electrode and gas

2.4.1 Pebricatien ofNiFe:Oa sensing layer ơn QCM 34 2.4.2 Gas scnsing measureiieii e si 135

CHAPTER 3 RESULTS AND DISCUSSIO!

3.1 Fabrication method iwestigation "—- ST

ABBREVIATIONS

BET Đrunauer — Finmell — Teller

BH Barrett — Joyner —Halenda

TTR Fourier Transform Infrared Spectroscopy

ICPDS Joint Committee on Powder Diffraction Standards

ITIMS International Training Institute for Materials Science

MFC Masa Flow Controller

NPs Nano particles

ppm Parts per million

QCM Quartz Crystal Microbalance

sccm Standard cubic centimeters per minute

SEM Scanning Electron Microscopy

TEM Transmission Electron Microscope