Nghiên cứu tạo lớp mạ tổ hợp ni ceo2 cuo định hướng ứng dụng làm chất xúc tác cho quá trình oxy hóa khí thải từ động cơ đốt trong tt tiếng anh

MINISTRY OF EDUCATION

MINISTRY OF NATIONAL

AND TRAINING

DEFENCE

ACADEMY OF MILITARY SCIENCE AND TECHNOLOGY

MAI VAN PHUOC

RESEARCH ON CREATING Ni-CeO2-CuO COMPOSITE PLATING
ORIENTED TO APPLICATION AS A CATALYST FOR OXIDATION
OF EMISSIONS FROM INTERNAL COMBUSTION ENGINES

Specialized: Chemical Engineering
Code: 9 52 03 01

SUMMARY OF ENGINEERING DOCTORAL THESIS

Hanoi - 2019


THIS DISSERTATION IMPLEMENTED IN
ACADEMY OF MILITARY SCIENCE AND TECHNOLOGY

Scientific supervisor:
1. Prof.Dr.Sci. Nguyen Duc Hung

Reviewer 1:

Prof.Dr. Mai Thanh Tung

Reviewer 2:

Assoc. Prof . Dr. Vu Thi Thu Ha

Reviewer 3:

Assoc. Prof . Dr. Nguyen Duy Ket

The defense of this dissertation will be held at the Academy of Military
Science and Technology Council,
at ...... ...... ……. in 2019

Contacting with the dissertation by:
- Library of Academy of Military Science and Technology.
- National Library of Vietnam.


1

INTRODUCTION
1. The necessity of the thesis:
Toxic substances such as carbon monoxide, hydrocarbons, solid
particles and NOx are usually emitted when gas and oil fuel being
used. These are substances that greatly affect human health and the
environment, as creating acid rain, photochemical blindness,
affecting the ozone layer, leading to climate change and the increase
of types of lung and cardiovascular diseases, especially cancers.

Therefore, it is necessary to remove these toxic substances from the
exhaust air stream before discharging into the environment.
Improvements in the structure and operation mode of the engine
cannot meet the requirements and standards of emissions. Therefore,
catalytic processor is the most effective tool to treat emissions to
achieve environmental standards.
Catalytic activity phases usually are precious metals such as
platin (Pt), rhodium (Rh), palladium (Pd). Recently, many studies
have shown that the catalytic activity of CeO2-based systems for
oxidation is significantly improved by doping not only precious
metals but also transition metals. Therefore, the discovery of
catalysts based on low-cost but highly catalytic transition metals has
attracted the attention of scientists. Among them, the mixture of CuO
and CeO2 is a catalyst with many preeminent properties to minimize
the pollution of engine exhaust. The catalytic activity of these two
oxide mixtures for oxidation reactions is comparable to catalysts
based on precious metals.
CeO2-CuO catalytic system can be made by various methods
such as co-precipitation, sol-gel, combustion, thermal decomposition,
precipitation
decomposition,
chelation,
impregnation,
hydrothermal, chemical plating, mechanical mixing metal oxides
together, ... By using these fabrication methods, to disperse the
CeO2-CuO catalyst on the catalyst carrier must first create a carrier
layer (commonly known as cordierite 2MgO.2Al2O3.5SiO2, γ-Al2O3),
then the catalyst layer disperses and adheres to monolithe substrate
(monolithe ceramic or metal monolithe).
CeO2-CuO catalyst can be created directly on the surface of steel

plate by making Ni-CeO2-CuO electroplating from CeO2 and CuO
nano catalytic particles. In particular, Ni acts as a binder, disperses
and binds CuO and CeO2 particles directly to the carrier without
creating intermediate substrate as other methods.


2

The above are the bases for PhD student to select and propose the
thesis topic "Research on creating Ni-CeO2-CuO composite plating
oriented to application as a catalyst for oxidation of emissions from
internal combustion engines".
2. Objectives of the thesis:
- Creating Ni-CeO2-CuO composite coatings on 430 stainless
steel.
- Finding the optimal conditions to creat Ni-CeO2-CuO composite
plating (direct current plating technique, pulse current plating
technique: current density, solid particle concentration, stirring
speed, plating time, ...).
- Determining the catalytic activity for oxidation of CO,
hydrocarbons of the emissions from internal combustion engine of
CeO2-CuO mixture on Ni-CeO2-CuO composite plating.
3. Main tasks of the thesis:
- Investigating the effect of CuO and CeO2 particles on the
discharge of Ni2+ ions in nickel sulphate solution by cathodic
potentiodynamic and electrochemical impedance spectroscopy.
- Surveying the technological parameters of direct current plating
technique affecting the content of CeO2 and CuO particles on the
platings.
- Investigating the technological parameters of pulse current

plating technique affecting the content of CeO2 and CuO particles on
the platings.
- Researching mechanical properties of Ni-CeO2-CuO composite
platings: corrosion resistance, abrasion resistance, thermal shock
stability, micro hardness.
- Evaluating the catalytic activity for oxidation of CO,
hydrocarbons of the emissions from internal combustion engine of
CeO2-CuO mixture on the Ni-CeO2-CuO composite plating.
4. Research methodogoly of the thesis:
- The effects of CuO and CeO2 particles on the discharge of Ni2+
ions in plating process was identified by cathodic potentiodynamic
measurements and electrochemical impedance spectroscopies.
- The content of CuO and CeO2 particles on the surface of NiCeO2-CuO composite platings was determined by energy dispersive
analyzer spectrum (EDX).
- The distribution of CuO and CeO2 particles on the platings was


3

determined by scanning electron microscopy method (SEM) and
element mapping.
- The catalytic activity of the composite platings was found out by
micro current-reaction method.
5. The significance of the thesis:
- Scientific significance: results of the thesis generate scientific
basis for electrochemical technology to make catalytic metal-CuO,
CeO2 nanocomposite coating.
- Practical significance: contribute to the establishment of plating
technology process of producing catalytic plating applied in the field
of engine exhaust treatment.

6. The layout of the thesis :
The 149-page thesis include: Introduction (4 pages); Chapter 1.
Overview (39 pages); Chapter 2. Experimental and Research
Methods (13 pages); Chapter 3. Results and discussion (73 pages);
Conclusions (2 pages); 146 references.
CHAPTER 1. OVERVIEW
- The overview of forming process of composite electroplating,
properties and applications of functional composite coatings.
- Engine exhaust components; exhaust treatment methods using
catalytic sets; domestic and foreign researches on engine exhaust
treatment by catalyts.
- Catalytic properties of CeO2 and CuO mixture and methods for
preparing them.
CHAPTER 2.
EXPERIMENTAL AND RESEARCH METHODS
2.1. Chemicals
- CeO2 (Richest Goup Ltd. Shanghai, China) and CuO (Nano
Global, Shanghai, China) are in nano size.
- Nickel sulphate, Nickel chloride, Copper sulphate, Boric acid,
Sodium lauryl sulphate, Sulfuric Acid, Hydrochloric Acid, Sodium
hydroxide: PA, China.
- Electrodes: Ni, Cu, Ti mesh coated RuO2.
Cathode material is 430 stainless steel sheet with thickness of 0.2
mm.
2.2. Experiments
- Research solution systems:


4

Table 2.1. The study solutions and symbols
Symbols

Composition of plating solution

S0

NiSO4.7H2O 300 g/L, H3BO3 30 g/L, sodium
lauryl sulphate 0.1 g/L

S0Cux

NiSO4.7H2O 300 g/L, H3BO3 30 g/L, sodium
lauryl sulphate 0,1 g/L, CuO nồng độ x g/L

S0Cey

NiSO4.7H2O 300 g/L, H3BO3 30 g/L, sodium
lauryl sulphate 0.1 g/L, CeO2 y g/L

S0CuxCey

NiSO4.7H2O 300 g/L, H3BO3 30 g/L, sodium
lauryl sulphate 0.1 g/L, CuO powder x g/L, CeO2
powder y g/L.

- Rectifier sources: direct current rectifier source and square pulse
reversed rectifier source at Institute of Chemical-Materials/Military
Science and Technology Institute.
Manufacture of catalytic core sets carrying Ni-CeO2-CuO

coating
Two 430 ferrit steel roll billets were cut along the length of the
roll to have a large length with a width of 25 mm, a thickness of 0.20
mm, in which one was used for forming laminating in length profile
of 6.5 m, another was used as buffer between two shaping layers
with the length of 5 m) as shown in Figure 3.49, 3.51.
Characteristics of catalyst:
- Catalytic core diameter: 120 mm
- Length: 100 mm (including 4 rolls)
- Gas contact surface area of catalytic core:
S = (Sflat plate + Sdeformation) x 2 = (5 x 0.025 + 6.5 x 0.025) x 2 x 4
= 2.3 m2.


5

Figure 3.49. Specification of
Figure 3.51. Mold for rolled shape
workpiece preparation to
machine
Creating steel foil profile was made by forming laminating
method.

Figure 3.52. Rolling the steel foil on the jig to create a coating (a)
and shaping together after coated the Ni-CeO2-CuO composite
plating (b)
2.3. The research methods
2.3.1. Research methods used to study the plating process
Cathodic potentiodynamic and electrochemical impedance
spectroscopy.

2.3.2. Methods and techniques used for evaluating the platings
- Scanning electron microscopy SEM, energy dispersive analyzer
EDX, element mapping;
- Hardness measurement of plating; abrasion resistance
measurement; characteristics of electrochemical corrosion of plating;
platings thermal shock stability measurement; acceleration test
assesses environmental durability.
- Catalytic activity of the platings determined on the microcurrent reaction system:


6

Figure 2.3. Principle diagram for determining the catalytic ability of
platings on the micro-current reaction system
CHAPTER 3. RESULTS AND DISCUSSION
3.1.Properties of nano CuO and CeO2
3.1.1. Morphology
3.1.1.1. SEM and TEM images
SEM and TEM images of CuO and CeO2 particles showed that
shape and size of these oxides were quite even.

Figure 3.1. SEM images of nano paricles: CeO2 (1a), CuO (1b); TEM
images of CuO (2a, 2b) and CeO2 (2c, 2d)
CuO and CeO2 particles had nano size. They were not in spherical
form but often angular, that gave advantages in the process of
burying particles into the plating layer.
3.1.1.2. EDX
XRD results of CeO2 and CuO particles were shown in figure 3.5
and 3.6, respectively.

Figure 3.5. EDX results of CeO2 particles


7

Hình 3.6. EDX results of CuO particles
3.1.2. Catalytic activity of CuO and CeO2 material particles for
conversion of CO and CxHy gas from engine exhaust

Độ chuyển hóa CO (%)

100
Bột CuO
Bột CeO2

80

Hỗn hợp bột
CuO/CeO2 = 1/7

60
40
20
0
0

50

100 150 200 250 300 350 400 450 500 550 600
Nhiệt độ (oC)

Figure 3.7. The conversion degree of CO and C3H6 gas of the CeO2
and CuO materials
The catalytic activity of mixture of CeO2 and CuO was higher
than the individual particle with the ability to convert CO gas got
100% at low temperature (300 oC). The catalytic ability for C3H6 gas
conversion of CuO and CeO2 mixture reached 96.18% at 450 oC. The
conversion degree increased and kept stable at a high level in the
temperature range of 200 oC to 500 oC. This result showed that it is
possible to use nano-sized CuO and CeO2 particles in the treatment
of CO, hydrocarbons in gasoline engine exhaust with high effective.
3.2. Properties of sulphate solution containing CuO and CeO2
particles used to create Ni-CeO2-CuO composite coating
3.2.1. Cathodic polarization curves
Polarization curves showed that the polarization decreased as
concentration of NiSO4 in solution increased. Therefore, it was
necessary to use a solution with a concentration of NiSO4 of about
250 ÷ 350 g/L. The thesis chosed the electrolyte solution of NiSO4
300 g/L for further studies.


8

i (A/cm2)

2 - NiSO4 100g/L

4

3 - NiSO4 200g/L

3

4 - NiSO4 300g/L

-0.08

-0.16

5

1 - NiSO4 50g/L

-0.12

2

5 - NiSO4 350g/L

1

-0.04

1
1- S0
2 - S0Cu4Ce4
3 - S0Cu8
4 - S0Ce8

-0.12

i (A/cm2)

-0.16

-0.08

2
3
4

-0.04

0.00

0.00

-0.4

-0.6

-0.8

-1.0

-1.2

-1.4

-0.4

-0.6

EAg/AgCl (V)

-0.8

-1.0

-1.2

-1.4

EAg/AgCl (V)

Figure 3.11. Cathodic
Figure 3.9. Cathodic polarization curves
polarization
curves of nickel
of nickel electrode in the electrolyte
electrode
in
the electrolyte
solution of NiSO4 (50 ÷ 350 g/L) +
0
H3BO3 (30 g/L) + sodium lauryl sulphate solutions: S , S0Cu8, S0Ce8
và S0Cu4Ce4
(0.1 g/L)
2+
The discharge potential of Ni in the sulphate solution and in the

composite plating solution were E* = -0.70 V (Ag/AgCl) and E* = 0.66 V (Ag/AgCl), respectively. When CeO2 and CuO particles were
added simultaneously to the sulphate solution, the cathode
polarization increased reducing the cathode discharge current at a
specific value of voltage, allowing plating with a smaller current
dgure 3.33. Effect of stirring speed on the total amount of CuO and
CeO2 on the composite coating

Figure 3.34. SEM images of composite coatings made at different
stirring speed
3.2.3.5. Influence of the ratio of CuO/CeO2 in electrolyte
Table 3.10. The content of CeO2 and CuO on the composite
coatings varied with the concentration of particles in electrolyte
Samples
Concent Concentr Content Content Ratio
Total
ration
ation of of CeO2 of CuO
of
content
of CuO CeO2 in
on the
on the
CuO/
of CeO2
in the
the
coating coating
CeO2 and CuO
electrol electroly (% wt)
(% wt)

on the
on the
yte
te
coating coating
x (g/L)
y (g/L)
M.S0Cu7Ce1

7.0

1.0

2.25

37.22

16.54

39.47

M.S0Cu6Ce2

6.0

2.0

4.12

34.64

8.41

38.76

3

5.0

3.0

5.04

31.08

1.23

36.12

M.S0Cu4Ce4

0

5

M.S Cu Ce

4.0

4.0

17.24

21.22

1.23

38.46

0

3

5

3.0

5.0

20.13

17.36

0.86

37.49

0

2

6

2.0

6.0

31.46

6.28

0.20

37.74

M.S Cu Ce
M.S Cu Ce

M.S0Cu1.6Ce6.4
0

1

M.S Cu Ce
0

0.8

1.6

6.4

31.90

4.46

0.14

38.18

7

1.0

7.0

33.78

3.46

0.10

37.24

0.8

0.8

7.2

34.68

2.15

0.06

36.83

M.S Cu Ce


18

The content of CeO2 and CuO on the composite coatings varied
greatly when the concentration of them in the electrolyte changed.
The content of CeO2 on the coatings increased from 2.25% to
34.68% when their concentration in the solution changed in the range
of 1.0 ÷ 7.2 g/L. The content of CuO on the coatings increased from
2.15% to 37.22% when their concentration in the solution changed in
the range of 0.8 ÷ 7.0 g/L. However, the total content of particles on
the composite platings changed from 36.83% to 39.47%.
3.2.4. Influence of some factors on the total content of CeO2 particles
and CuO on platings made by pulse galvanizing technique
3.2.4.1. Influence of concentration of CeO2 and CuO particles in
electrolyte
The dependance of content of CeO2 and CuO on the composite
coatings on the particles’ concentration in electrolyte was shown in
figure 3.36.

Figure 3.36. Influence of total concentration of CeO2 and CuO

particles in electrolyte on particles’ content on the composite coating
SEM images of the surface of the platings (Figure 3.37) showed
that the distribution of solid particles on the surface of the platings
corresponding to the results of plating composition.

4 g/L

6 g/L

8 g/L

10 g/L

12 g/L

16 g/L


19

Figure 3.37. SEM images of Ni-CeO2-CuO composite coatings varied
with different particles concentration in electrolyte
3.2.4.2. Influence of average pulse current density
Table 3.11. Total amount of CeO2 and CuO on the Ni-CeO2-CuO
composite coatings (% wt) made under different pulse conditions
Pulse current density (A/dm2)
Parameter
ic
ia
ic

ia
ic
ia
itb
itb
itb
α = β = 0.2
2.5 0.5 2.0 5.0 1.0 4.0 7.5 1.5 6.0
Particles, %

25.46

37.69

32.18

The content of CeO2 and CuO on the composite coatings
increased to got the highest value of 37.69% when itb increased to 4
A/dm2.
3.2.4.3. Influence of ratio of anode current density/cathode current
density
EDX results of the components of CeO2 and CuO particles on the
composite platings at different  ratios were shown in table 3.12.
Table 3.12. Total amount of CeO2 and CuO particles on the
composite coatings made at different values of 
Total content of
ic
ia
itb
β

particles on the

(A/dm2) (A/dm2)
(A/dm2)
coatings (%)
0.1 0.2
4.9
0.49
4
34.51
0.2 0.2
5.0
1.0
4
37.69
0.3 0.2
5.1
1.53
4
28.62
0.4 0.2
5.2
2.08
4
13.04
The appropriate range of value of  was 0.1 ÷ 0.2, in which total
amount of CeO2 and CuO particles on the composite coatings
reached the highest value of 37.69% at  = 0.2.

β = 0.2

β = 0.4
Figure 3.24. SEM images of composite coatings made at β = 0.2 and
β = 0.4, magnification of 10.000


20

3.2.4.4. Influence of ratio of anode time/cathode time ()
Total amount of CeO2 and CuO particles on the composite
coatings reached the highest value of 37.69% at  = 0.2 and
decreased clearly when  increased to 0.4.
3.3. Mechanical, physical and chemical properties of Ni-CeO2CuO composite plating
- Corrosion resistance of the coating: Ni-CeO2-CuO composite
plating had a very small corrosion current of 1.601.10-5 (A/cm2) that
was smaller than the corrosion current as well as the corrosion rate of
pure nickel plating – 1.688.10-5 (A/cm2).
- Abrasion resistance of the plating: the abrasion resistance of NiCeO2-CuO composite coating was 4.2 times greater than that of pure
Ni coating.
- Microhardness of the coating: the microhardness of Ni-CeO2CuO composite plating was 240.40 HV, which was 1.5 times greater
than that of pure nickel plating made from sulphate solution of
163.16 HV.
- Adhesion of the coating: the composite coating still adhered to
the background without peeling after thermal shock test.
- Test the resistance to salt frost and moist heat of the coating:
The coating did not blister. There were no stains and other
irregularities on the surface of the platings.
3.4. Catalytic activity of Ni-CeO2-CuO composite coatings for
conversion of engine exhaust gas
Catalytic activity of Ni-CeO2-CuO composite coatings for CO
conversion

Ni plating
CuO-CeO2 1:7

100

100
CuO/CeO2 = 1/7

80

CuO/CeO2 = 1/10
CuO/CeO2 = 1/15

60
40

CO conversion (%)

Độ chuyển hóa CO (%)

CuO/CeO2 = 1/5

CuO-CeO2 1:7 mix powder

80
60
40
20

20

0

0

0

0

50 100 150 200 250 300 350 400 450 500 550 600

50

100

150

200

250

300

350

400

450

500

550

600

Temperature (oC)

Nhiệt độ (oC)

Figure
3.45.
Catalytic
efficiency of CO-conversion of
Ni-CeO2-CuO
composite
coatings containing different
ratios of particles

Figure
3.46.
Catalytic
efficiency of CO-conversion of
pure Ni plating, Ni-CeO2-CuO
plating and CuO + CeO2
mixture


21

Catalytic activity of Ni-CeO2-CuO composite coatings for CxHy
conversion

CuO/CeO2 = 1/10

60
40

Ni planting
CuO/CeO2 = 1/7

100

CuO/CeO2 = 1/5
CuO/CeO2 = 1/7

80

CuO/CeO2 = 1/7

C3H6 conversion (%)

Độ chuyển hóa C3H6 (%)

100

80

mix powder

60
40
20

20

0

0

0

0

50 100 150 200 250 300 350 400 450 500 550 600

50

100 150 200 250 300 350 400 450 500 550 600
Temperature (oC)

Nhiệt độ (oC)

3.48.
Catalytic
Figure 3.47. Catalytic efficiency Figure
efficiency
of
C
H
-conversion
of
3 6

of C3H6-conversion of Ni-CeO2430
steel
substrate
coated
Ni,
CuO
composite
coatings
0
1.6
6.4
containing different ratios of S Cu Ce composite coating
and CuO + CeO2 mixture
CuO and CeO2 particles
The catalytic activity of Ni-CeO2-CuO nanocomposite coatings
was highly dependent on the mass ratio of CuO and CeO2 particles
on the surface. The composite coating had the best catalytic activity
at the ratio of CuO/CeO2 = 1/7, in which the conversion of CO got
100% from 300 oC; the conversion of C3H6 reached the highest value
of 85.76% at 500 oC.
3.5. Test results of catalytic activity for conversion of engine
exhaust gas of Ni-CeO2-CuO composite coating
The catalytic effect of exhaust treatment with an oxygen sensor motor

Figure 3.53. HC emission at temperature of 270 oC, 147 oC
Results from Figure 3.53 showed that the reduction in average
HC emission was 45.8 ppm.

Figure 3.54. CO emission in case with and without BXT

22

The results in Figure 3.54 showed that reduction of average CO
emission was 0.02 vol%. In this case the catalyst had little effect to
reduce CO concentration.
The catalytic effect of exhaust treatment with internal combustion
engine that did not have oxygen sensors:
The results in Figure 3.55 and Figure 3.56 showed that the
reduction of HC and CO average emission were 100 ppm and 3.2%
vol. The conversion efficiency was relatively high, indicating that
this catalyst was suitable for an internal combustion engine that did
not have oxygen sensors.

Figure 3.55. HC emission in case with and without BXT

Figure 3.56. CO emission in case with and without BXT
CONCLUSIONS
* Research results of the thesis:
1. The changes of concentration of CuO and CeO2 nanoparticles
in the composite plating solution virtually unchanged the shape of
cathodic polarization curve but affected on cathode polarization
leading to the change of the discharge potential of Ni2+ in the
sulphate solution. There were two processes including charge
transfer and adsorption taking place simultaneously, but the
adsorption process controlled the speed of the reaction in S0CuxCey
solution.
2. Ni-CeO2-CuO composite plating made by direct current
galvanizing technique from sulphate solution containing NiSO4 300
g/L, H3BO3 30 g/L, sodium lauryl sulphate 0.1 g/L, total content of

23

CeO2 and CuO 8 g/L at current density 2 A/dm2, stirring speed 600
rpm, temperature 50 oC, plating time 20 minutes had the highest
amount of particles of 38.46%.
Ni-CeO2-CuO composite plating made by pulse current
galvanizing technique under plating condition: itb = 4 A/dm2, β = 0.2;
f = 100 Hz; CeO2 5 g/L; CuO 5 g/L; stirring speed 600 rpm,
temperature 50 oC, plating time 20 minutes had 37.69 % CeO2 and
CuO.
Ni-CeO2-CuO composite platings made from the electrolyte
containing 10 ÷ 16 g/L particles under revered square pulse had
higher content of particles compared to platings made under direct
current.
3. The presence of CeO2 and CuO particles on Ni layer improved
some mechanical properties of the plating: increased microhardness
of the coating (reached the value of 240.40 HV); increased the
abrasion resistance of Ni-CeO2-CuO composite coating (4.2 times
greater than that of pure Ni coating); corrosion rate of Ni-CeO2-CuO
composite plating on steel substrate was very small, and the plating
was resistant to level 3 of wet heat resistance test, harsh frost
resistance test and thermal shock resistance test.
4. Ni-CeO2-CuO composite coating fabricated on 430 steel
substrate from the solution containing NiSO4 300 g/L, H3BO3
30 g/L, sodium lauryl sulphate 0.1 g/L, CeO2 6.4 g/L and CuO
1.6 g/L at current density 2 A/dm2, stirring speed 600 rpm,
temperature 50 oC, plating time 20 minutes had total amount of
particles of 38.18% (in which mass ratio of CuO/CeO2 was 1/7) had

CO conversion of 100% at 300 oC which was as high as that of the
mixture of two oxide powder. The highest C3H6 conversion efficency
of this coating was 85.76% at 500 oC.
5. Ni-CeO2-CuO composite coating was fabricated on a catalytic
core made from 430 steel foil that reduced CO and hydrocarbons
average emission of 100 ppm and 3.2% vol. This showed that the
catalyst was suitable for internal combustion engines that did not use
oxygen sensors.
* News findings of the thesis:
- The thesis coordinated research on electroplating techniques and
catalysts on plating.
- Clarified the nature of the composite plating process by
polarization curve and electrochemical impedance spectroscopy


24

measurements.
Created Ni-CeO2-CuO composite coating on 430 steel substrate
by direct current and reversed pulse square technique that can be
catalyst for the engine exhaust treatment.
* Further researches:
- Further research on the influence of pulse-plating techniques on
the distribution of CuO and CeO2 particles on the composite coating
surface.
- Study to overcome the passive surface electrodes.
- Practical test to determine durability, catalytic life of the plating
on engine.

PUBLISHED SCIENTIFIC WORKS CONCERNING THE
THESIS
1. Nguyen Đuc Hung, Trinh Thi Hoàng Anh, Mai Van Phuoc, Đao
Khanh Du, Characteristics of the steel sheet plated Ni-CeO2-CuO
composite, Journal of Research Military Science and Technology, No
43, 2016, 149-155.
2. Nguyen Duc Hung, Tran Thi Van Nga, Mai Van Phuoc, Thickness
determination and control of function Ni-Composite electrodeposited
coatings, Journal of Science and Technology, 55 (B1), 2017, 1-6.
3. Mai Van Phuoc, Nguyen Duc Hung, The study on catalytic
activity of composite plating Ni-CeO2-CuO for CO oxydation, Viet
Nam Journal of catalysis and adsorption, T.6, N0.2, 2017, 142-147.
4. Mai Van Phuoc, Nguyen Duc Hung, Corrosion protection and
chacracteristics of Ni-CeO2-CuO electroplating layer on steel
substrate, Journal of Science and Technology, 55 (5B), 2017, 181186.
5. Mai Van Phuoc, Nguyen Duc Hung, Some factors affecting on the
composition of CeO2 and CuO in Ni-CeO2-CuO composite plating
coating, Journal of Research Military Science and Technology, Số
đặc san, 2018, 130-135.
6. Mai Van Phuoc, Nguyen Duc Hung,
Electrochemical
characteristic of the sulfate solution in the formation of the Ni-CeO2CuO composite plating, Vietnam Journal of Chemistry, Volume 56,
Number 4e1, September 2018.
7. Mai Van Phuoc, Nguyen Đuc Hung, Study of influencing factors
one composition of CeO2 and CuO in Ni-CeO2-CuO composite
plating on the 430 steel by using pulse plating., Journal of Research
Military Science and Technology, N0. 57, 10- 2018, 129-135.
8. Nguyen Duc Hung, Tran Thi Van Nga, Le Thi Phuong Thao, Mai
Van Phuoc, “Plating technology of nano, micro composite Ni-CeO2CuO; Ni-TiO2 and Ni-CBN for manufacturing of functional
coatings”, Vietnam-UK Researcher links Workshop Green

electrochemical and materials processing for environment and
energy challenges, Hanoi 30 Octo - 02 Novem 2018, Hanoi
University of Science and Technology, VietNam.