Synthesis of nano niCkel oxide and the ability of compounds containing niCkel to catalyze CO(g) oxidation

Synthesis of nano niCkel oxide and the ability of compounds containing niCkel to catalyze CO(g) oxidation

SYNTHESIS OF NANO NICKEL OXIDE AND THE ABILITY OF COMPOUNDS CONTAINING NICKEL TO CATALYZE

CO(g) OXIDATION

wa Some sunlight that hits

the earth is reflected

Some becoImes heat

Global Warming Greenhouse Effect

Introduction

Sources of air pollution

ier co ot Noricy are

transport and = solvents and

‘Combustion of | Fue! combustion, Exhaust, brak

coal, oil, gas, process and tyre and

bioenergy emissions road wear, transformation waste

and waste fuel evaporation of fossil fuels

Overview of some oxides containing Ni

C2 02

4N'+O, >4Ni*+ 2 O2

Overview of some oxides containing Ni

Overview of some oxides containing Ni

e One unit cell has 8 AB,O, molecules including

Overview of some oxides containing Ni

Overview of some oxides containing Ni

e Perovskite (ABO.) often has orthorhombic or rhombohedral or tetragonal structure

¢ Characteristics: conducted properties and

active oxygen

¢ A, B is often replaced by other elements to

Increase oxy-hole — increase reactivity

Adsorption on some oxides

containing Ni

¢ Based on semi-conducted properties of oxides

(Temperature / > ability of conduction 7)

¢ Actually, those are redox reaction

e H,, O,, CO can be adsorbed strongly on some

oxides containing Ni

How to increase reactivity of catalyst

How to increase reactivity of catalyst

¢ Valence adjusting method

¢ Synthesis irregular compounds method

Oxidation on catalyst

¢ Completed oxidation > CO,, H,O

Their applications: to remove some gases In

synthesis Oxo

¢ Selected oxidation > organic compounds

containing oxygen

This is the main method to synthesize

compounds containing oxygen such as carboxylic acids, anhydrides, oxides

Applications of catalyst containing Ni

CO+%0,— C0,

Or

CH, VOCs + O, — CO, + H,O

x yy?

Results: perovskite NiIMnO.,, La, Sr,CoO.,

La, Eu.CoO., La, SrNiO,, va La, Sr FeO,

Synthesis some oxides containing Ni

Precipitaiting method

¢ Quick rate

¢ Products are insoluble in solvent

— experiments of Sivakumar, Maluf,etc

Sol-gel method

— experiments of Yang, Lima,etc

Burning gel method

—experiments of Souza, Mridula Biswas,etc.

Synthesis of nanoscale nickel oxide

¢ Method: burning the gel PVA

¢ The role of PVA:

— As homogenous dispersing agent for metal cation

— Coordinating with metal cation to yield complexes

— Providing heat for the burning gel

¢ Test product: DTA-TGA, XRD, FTIR.

Synthesis of nanoscale nickel oxide

1 Thermal analysis of the gel Ni#-PVA:

Method: DTA-GTA

Result: 50 - 400°C, especially the maximum

loss of the weight of the gel at 305.18°C

> 400°C: no effects

After forming, the gel is dried at 80°C until

spongy and porous

The porous gel is baked between 300 - 600°C

Synthesis of nanoscale nickel oxide

¢ Using the XRD method to investigate and

choose an appropriate temperature

Synthesis of nanoscale nickel oxide

¢ Using FTIR spectroscopy to prove the presence of

the single crystal of NiO

Synthesis of nanoscale nickel oxide

2 Affecting of pH to the gel Ni#-PVA:

¢ pH: an important parameter in material synthesis In solution

Synthesis of nanoscale nickel oxide

® Inthe process of synthesis metal oxide by the method of

burning the gel PV:

— The low pH (1-3): low viscosity and less spongy gel

— The higher pH (4-5): more porous gel

Explain: In water, PVA are dipole that have linkage

together and co-ordinate with metal as a complex

> In low pH: weak co-ordination In high pH, the precipitation of metal as hydroxide

=> PVA Is a source of fuel.

Synthesis of nanoscale nickel oxide

3 Affecting of the molar ratio of Ni#/PVA

¢ Changing the molar ration of Ni#*/PVA | |changing the nanoscale size of NiO-crystalline

¢ The ratio: 1/6; 1/3; 1/1; 3/1; 6/1

Synthesis of nanoscale nickel oxide

Synthesis of nanoscale nickel oxide

4, Affecting of temp to the forming gel process

Synthesis of nanoscale nickel oxide

¢ At 40°C and 60°C, dispersion of Ni“ in PVA Is

slow | |the forming gel is time-consuming

e At 100°C, the forming is so fast, and H,O

rapidly vapors [| pH is changed and the gel is less porous

¢ At 80°C, sufficient time to ensure pH and

viscosity | | absence of Ni

Synthesis of nanoscale nickel oxide

Conditions of the forming gel Ni2*-PVA

pH The molar ratio Ni7*/PVA Temp (°C)

Catalyzing oxidation of CO on some oxides

containing nickel

Purposes:

¢ Ability of oxides containing Ni to catalyze CO oxidation

¢ How does replacement of elements In oxides

containing Ni influence on catalysis?

Ability of oxides containing Ni to catalyze

Co(IIT)

LaNiO,

Perovskite La, Ce NIO,

Mixed oxide Ce, NiO,

PerovsKite LaNiï, Co O

X