Hydrogen Sensor

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