KIEM DO VAN
MINISTRY OF EDUCATION AND TRAINING
PHENIKAA UNIVERSITY
KIEM DO VAN
ELECTROSYNTHESIS OF Sn AND SnO2 NANOSTRUCTURES
TOWARDS GAS SENSING AND WATER SPLITTING
APPLICATIONS
DOCTORAL DISSERTATION ON MATERIALS SCIENCE
2025
Hanoi – 2025
MINISTRY OF EDUCATION AND TRAINING
PHENIKAA UNIVERSITY
KIEM DO VAN
ELECTROSYNTHESIS OF Sn AND SnO2 NANOSTRUCTURES TOWARDS
GAS SENSING AND WATER SPLITTING APPLICATIONS
DOCTORAL DISSERTATION ON MATERIALS SCIENCE
Code: 9440122
Supervisors:
1. Assoc. Prof. Dr. Tu Le Manh
2. Prof. Dr. Nguyen Van Hieu
Hanoi-2025
i
DECLARATION OF AUTHORSHIP
Kiem Do Van, hereby solemnly declare that this Ph.D. thesis titled
“Electrosynthesis of Sn and SnO2 nanostructures towards gas sensing and water
splitting applications” is entirely the result of my work conducted at Phenikaa
University under the supervision of Assoc. Prof. Dr. Tu Le Manh and Prof. Dr.
Nguyen Van Hieu. All experiments, data analysis, and interpretations presented in
this thesis comply with the ethical guidelines and legal requirements. Any
collaboration with other researchers has been appropriately acknowledged. This
study has not been submitted, either partially or in full, for a qualification at any other
institution. I fully understand the significance of academic integrity and take
complete responsibility for the content and quality of this work./.
Hanoi, October 06th, 2025
Supervisor 1
Assoc. Prof. Dr. Tu Le Manh
Ph.D. Student
Kiem Do Van
Supervisor 2
Prof. Dr. Nguyen Van Hieu
THESIS CONTENT VERIFICATION BY THE COMPETENT
DEPARTMENT
ii
ACKNOWLEDGMENTS
I am profoundly grateful to everyone who has offered unwavering support,
encouragement, and invaluable guidance throughout my Ph.D. journey. There is
always a risk of leaving someone out when writing acknowledgments. To prevent
this, I would like to start by expressing my gratitude to all the people who have
contributed to this thesis in any way. Nevertheless, some special individuals deserve
particular recognition for their exceptional assistance.
First and foremost, I would like to express my sincere appreciation to my supervisors,
Assoc. Prof. Dr. Tu Le Manh and Prof. Dr. Nguyen Van Hieu for their exceptional
mentorship and academic wisdom. Their insightful guidance and constructive
criticism have been instrumental in shaping the direction and quality of my
dissertation. I am thankful for their expertise, patience, and continuous
encouragement, which have been fundamental to my development as a researcher.
I am thankful to Prof. Thomas CK Yang and Dr. Sridharan Balu at the Department
of Chemical Engineering, National Taipei University of Technology (NTUT),
Taiwan; Assoc. Prof. Chi-Wen Lung at the Asia University, Taiwan, for their
enthusiastic assistance with material analysis. In particular, I would like to express
my gratitude to the National Science and Technology Council (NSTC), Taiwan,
which funded me for two International internships (2023 and 2024). Based on this
reward, I am concerned about completing my PhD thesis with my best effort.
I would also like to express my gratitude to all members of the Nanosensors
Laboratory, Applied Electrochemical Laboratory, and Phenikaa University Nano
Institute, Phenikaa University, for establishing a professional academic setting that
has greatly enhanced my research.
Finally, I wish to express my deepest appreciation to my family for their
unconditional love and unwavering support. Their constant encouragement,
understanding, and sacrifices have been crucial in sustaining my dedication
throughout this academic journey.
Hanoi, October 6th, 2025
Ph.D. Student
Kiem Do Van
iii
TABLE OF CONTENTS
TABLE OF CONTENTS ......................................................................................... iii
INTRODUCTION ....................................................................................................... 1
CHAPTER 1. LITERATURE REVIEW .................................................................... 8
1.1. Introduction ....................................................................................................... 8
1.2. Thermodynamics and kinetics of electrodeposition ....................................... 10
1.2.1. Thermodynamic principles ....................................................................... 10
1.2.2. Kinetics of metal electrodeposition .......................................................... 12
1.2.3. Nucleation and growth of metals in the electrochemical system. ............ 12
1.2.4. Electronucleation and growth mechanism ............................................... 13
1.2.5. Literature review on electronucleation and growth of Sn and its alloys. . 20
1.3. Overview of MOS gas sensors ....................................................................... 22
1.3.1. General principles of gas sensors ............................................................. 22
1.3.2. Basic performance parameters of gas sensors .......................................... 23
1.3.3. Gas sensing mechanism of gas sensor based on MOSs ........................... 25
1.3.4. Literature review on gas sensors fabricated by electrodeposition ........... 26
1.4. Fundamentals of electrocatalysts .................................................................... 28
1.4.1. Electrocatalytic parameters ...................................................................... 29
1.4.2. Electrocatalyst for water splitting reaction ............................................... 30
1.4.3. Electrodeposition of electrocatalysts for water splitting application ....... 33
1.5. Conclusions of Chapter 1. ............................................................................... 35
CHAPTER 2. MATERIALS AND METHODS ....................................................... 36
2.1. Electrolytes preparation .................................................................................. 36
2.2. Electrochemical tests ...................................................................................... 37
2.2.1. Cyclic voltammetry (CV) ......................................................................... 37
2.2.2. Chronoamperometry (CA) ....................................................................... 39
2.3. On-chip electrodeposition of Sn/SnO2 on PtME. ........................................... 40
2.3.1. Studying single gas sensor chips .............................................................. 40
2.3.2. Study on multiple gas sensor chips .......................................................... 41
