Unit 3 Chemistry - FUEL CELLS

porous electrode

electrode with many holes (pores) which is used in a fuel cell to maximise the ability for gaseous reactants to come into contact with the ions in the electrolyte

Electrochemical Cell

a device that transforms chemical energy into electrical energy

Electrochemical Series

a series of reduction half-cell reactions and their standard electrode potentials

Electrode

solid conducting material that can carry electric current (surface at which oxidation and reduction reactions take place on)

Fuel Cell

An electrical-chemical device that converts fuel, such as hydrogen, into an electrical current and requires a continuous supply of reactants

hydrogen economy

the concept of using hydrogen as the fuel for industry, transport and electrical generation

Internal circuit

The part of an electrochemical cell in which ions move, e.g. solutions/electrolyte

linear econ

An economy based on the make, use, dispose model.

Natural resources -> take -> make -> distribute -> use -> dispose

Oxidising agent (oxidant)

ACCEPTS electrons from another substance, causing that substance to be oxidised. The oxidant is itself reduced

Reducing agent (red

DONATES electrons to another substance, causing that substance to be reduced. The reductant itself is oxidised

Standard Conditions (for formation of electrochemical series)

25 degrees celsius, 100 kPa and 1.0M solutions

volt

The unit of potential difference symbolized as V.

Reactant at cathode that is always reduced

Oxygen gas

Electrolyte

An ionic compound whose aqueous solution conducts an electric current

Alkaline electrolyte

Contains hydroxide ions (OH-) e.g. KOH

Acidic electrolyte

Contains hydrogen ions (H+) e.g. H3PO4

Steam reforming

methane gas + steam (with Ni catalyst) -> hydrogen gas + carbon monoxide gas
CH4 (g) + H2O (g) -> 3H2 (g) + CO (g)

Anode

the electrode at which oxidation occurs and has a neagtive polarity

Biogas

A mixture of methane and carbon dioxide produced by bacterial degradation of organic matter and used as a fuel.

Cathode

the electrode at which reduction occurs and has a positive polarity

Circular econom

An economy model in which resources remain in use for as long as possible, from which maximum value is extracted while in use, and the products and materials are recovered and regenerated at the end of the product life cycle.