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Submitted to: Mrs. Anubhawi Annu
Deptt. Of NanotechnologyLovely Professional
University
Submitted by:Vir Sapan Pratap Anand
11202530Section : B1205Roll No. : A07
Term Paper PresentationNTY319::Nanofabrication
Topic : Hydrogen Gas Sensor
Types of Hydrogen SensorSensing Materials for hydrogen sensor
ApplicationsAdvantages and Disadvantages
Hydrogen Sensor:Topics To be discussed
Detects presence of hydrogen Contain Micro fabricated point contact sensors
Used to locate leaks They are considered: Low Cost Compact Durable Easy to maintain
Hydrogen Sensor : A brief introduction
Optical Fibre hydrogen SensorMEMS Hydrogen SensorThin film SensorThick Film SensorChemo chromic Hydrogen sensor
TYPES OF HYDROGEN SENSORS:
PALLADIUM Selectively absorbs hydrogen gas Forms the compound Palladium hydride
Other Properties Have strong temperature dependence Response time large at low temp. To be protected against
1. Carbon Monoxide2. Sulphur dioxide3. Hydrogen sulphide
Which element plays a major role in detection ??
They are used for the point detection of hydrogen.
They Use Surface Plasmon Resonance. Now what is Surface Plasmon Resonance ? Resonance oscillation of conduction e- at the interface of +ve and –ve
permittivity material It is stimulated by incident light
Optical Fiber Hydrogen Sensor
When a nano particle is much smaller than the wavelength of light,
Coherent oscillation of the conduction band electrons is induced
by interaction with an electromagnetic field This resonance is called Surface plasmon
resonance
Surface Plasmon Resonance Concept :
Optical fibre hydrogen sensor : Consists of fibre bragg, micro mirror and tapered fibre coated with palladium
Fiber bragg detects the hydrogen Hydrogen changes the refractive index of
the palladium.
Types of Hydrogen Sensor
MEMS based hydrogen sensor coated with a film
Nanostructured film made of Indium Oxide In2O3 and Tin Oxide SnO2
A free standing cantilever is coated with Pd. In the presence of hydrogen, the Pd layer
expands and form a stress on the cantilever. Cantilever bends. Resonators are used. A shift is caused in resonance frequency due to
stress in cantilever.
MEMS Based hydrogen sensor
There is a thin film. Nanosized palladium particles swell when
the hydride is formed. In the process of expanding, some of them
form new electrical connections with their neighbours.
As conductive pathway increase, the resistance decreases.
Thin Film Sensor
It relies on electrical resistance of palladium hydride is greater than metallic resistance.
Absorption of hydrogen causes a measurable increase in electrical resistance.
Thick Film Sensor
Chemochromic Hydrogen Sensor : There is a smart Pigment paintIt visually identifies hydrogen leaksThere is a change in colourAlso available as a tape
Detects Hydrogen leakage ini) Power plants : sensors shut off the
hydrogen source or activate alarmsii)Fossil fuel oil refining : Hydrogen can
escape while refiningiii) Hydrogen off gasing from nuclear wasteiv) Hydrogen refueling and gas stations. v) Reducing atmosphere furnaces
Applications
Can be affected by humidity and water There is a temperature limitation. Dust and dirt can coat the optics and
response can be impaired
Disadvantages of Hydrogen Sensors
Hydrogen sensors are of various types. Palladium is most common element used. Each type has own principle Hydrogen sensors have various applications
such as in power plants and fossil fuel refining.
It has few disadvantages as well as explained before.
Conclusion