PPT Isfache 2014- Diah Susanti

8/10/2019 PPT Isfache 2014- Diah Susanti

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Preparat ion o f CO gas senso r f rom ZnOMater ial Syn thesized via Therm o -Oxidat ion

Process

Diah Susanti*, Endah Lutfiana, HaniffudinNurdiansah, Hariyati Purwaningsih, Lukman

Noerochiem#Materials and Metallurgical EngineeringDepartment,ITS Surabaya

*Corresponding Author :[email protected]



Introduction



Purposes of the Research

• Synthesis ZnO via Thermo – OxidationProcess

• Arrange a CO gas sensor based on ZnOmaterial

• Analyzed the correlations between ZnOstructure and sensitivity towards CO gas



Literature : CO Toxicity



Literature : CO Reaction

Hb(aq) + CO(g) → HbCO(aq)



Literature ZnO

Tabel 2.1 Characteristic

of ZnO (Wikipedia, 2013)

ZnO Powder



Literature Sensor

S =[ − ]

A sensor is a device that detectsevents or changes in quantitiesand provides a correspondingoutput, generally as an electricalor optical signal

SensitivityEquation

Rg : Resis tanc e af tergas exposure

Ro : Resis tance beforegas exposure



Oxidation: 1/2 O 2 g + e - O ad- Reduction : CO + O ad- CO 2

g + e -

Literature Gas Sensor Mechanism



Flow Chart of Experiment

Specimen is already to used

Sintered at T : 500 0C for 1 hour

Pelletizing using hydraulic compaction machine with pressure 200 bar to obtainpellets with dimension 14 mm in diameters and 3 mm in thickness

Crushed and sieved until the sizes less than 80µm

Hold for 40 minutes

Zn powder ( 2mg), heated at muffle furnace with various temperature of 800, 850,

and 9000

C



Synthesis of ZnO

Zn powder < 45 µ Muffle Furnace T : 800, 850,900 oC ,40 minutes Crushing ZnOPowder

Shieving < 80 µ



Powder Compaction (200Bar)

(SEM),(XRD),(BET)

Making A Pellet Sensor

SensitivityTesting

Sintering at 500 oC



Testing

Testing

SEM

XRD

Sensitivity

Testing

BET



1. Gasometer of CO2. Vacuum Pump3. Mass Flow

Controller4. Thermocontroller5. Chamber6. Electrical

MeasuringInstrument

Sensitivity Testing

1 2

3 4 5 6



Flow Chart of Sensitivity Testing

Repeated step above for different operating temperature 50 and 1000

C

Repeated this step at different CO gas concentration 100, 250 and 500 ppm

Calculate the Rg using potentiostat

Flowing the CO gases at 10 ppm concentration

Calculate the R 0 using potentiostat

Put the ZnO pellet into the chamber, and then vacumm it and set the operation

temperature at 300

C using thermocontroller



Picture of ZnO Pellet



XRD Testing :Before Exposure

Fig.1 Comparison of thediffraction patterns of ZnOpellets synthesized at 800 0C,850 0C, and 900 0C beforesensitivity test towards COgas.



XRD Testing : After Exposure

Fig.2 Comparison of diffraction patternof ZnO pellets for sample with synthesistemperature variations 800 0C, 850 0C,900 0C, after exposure to CO gas.



SEM Testing : ZnO BeforeCrushed

Fig.3 Bright field SEM images for ZnO before being crushed intopowder, synthesized at a) 800 0C, b) 850 0C, and c) 900 0C.



SEM Testing : ZnO Before GasExposure

Fig. 4. Bright field SEM images of ZnO pellets for sample with varioussynthesis temperature a) 800 0C, b) 850 0C, and c) 900 0C before CO gasexposure



SEM Testing : ZnO After GasExposure

Fig. 5. Bright field SEM images of ZnO pellets for sample with varioussynthesis temperature a) 800 0C, b) 850 0C, and c) 900 0C after CO gasexposure



BET Testing



Sensitivity Testing

Fig. 6. Thesensitivity test ofZnO-based CO gassensorsynthesized atvarioustemperatures 800,

850, and 900 0C atdifferent operatingtemperatures 30,50 and 100 0C andCO gasconcentration)a)10ppm, b)100ppm, c)250ppm, d)500ppm



Conclusion• ZnO as material for CO gas sensor could be obtained through

thermo-oxidation process of Zinc powder.• XRD measurements confirmed the formation of ZnO of hexagonal

structure without any other impurities.• The ZnO sensor pellet synthesized at 800 0C performed the highest

sensitivity towards CO gas for its largest active surface area. It wasalso showed that the sensitivity towards CO gas increased withoperating temperature and CO gas concentration.

• SEM and XRD analysis have also revealed the potency of ZnOmaterial for CO gas sensor, since there was no significant change inthe morphology and structure of ZnO material after CO gasexposure.

• Therefore ZnO is a good candidate for CO gas sensor material sinceit is stable and inert to CO gas.



Acknowledgements

• Authors gratefully acknowledge thefinancial and facility supports from Ministryof Education and Culture Republic of

Indonesia through InternationalCollaboration Research Grant 2014(BOPTN funding) and Institut Teknologi

Sepuluh Nopember (ITS) - SurabayaIndonesia, respectively.



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PPT Isfache 2014- Diah Susanti