16B.1 Flashcards
what is a fuel cell
a cell that produces a voltage from a chemical reaction between the fuel and oxygen
what fuels are commonly used in the fuel cell
- hydrogen
- methanol/ethanol
- hydrogen rich methanol
in hydrogen-oxygen fuel cell, both metal electrodes are coted with
platinum
why are both metal electrodes in a hydrogen-oxygen fuel cell coted with platinum
catalysis the reaction that takes place at the electrodes
what are the two reactions that take place in a hydrogen-oxygen fuel cell in the presence of a acidic electrolyte
at the negative electrode” H2(g —-> 2H+(aq) + 2e-
at the positive electrode 0.5O2(g) +2H+(aq) +2e- —–> H2O(l)
how does the reactions happen within the Hydrogen-Oxygen fuel cell in a presence of a acidic electrolyte occur
hydrogen gas is fed into the cell it would then react at the acidic electrode causing it to lose electrons that flow in the circuit, the H ions formed would then pass through a proton exchange membrane where they would meet the positive electrode where oxygen is being fed, so the H and the O and the electrons found within the circuit which came from the original hydrogen gas would react forming water as a bi standard
what is the overall reaction of Hydrogen-oxygen fuel cell in the presence of a acidic electrolyte
H2(g) + 0.5O2(O) —–> H2O (l)
what are the two reactions that take place in a hydrogen-oxygen fuel cell in the presence of a alkaline electrolyte
at the negative electrode: H2(g) + 2OH-(aq) —–> 2H2O(l) + 2e-
at the positive electrode: 0.5O2(g) + H2O(l) + 2e- —–> 2OH-(aq)
what is the overall reaction of Hydrogen-oxygen fuel cell in the presence of a acidic electrolyte
H2(g) + 0.5O2(O) —–> H2O (l)
how does the reactions happen within the Hydrogen-Oxygen fuel cell in a presence of a acidic electrolyte occur
Hydrogen gas that’s fed into the fuel cell would react with the Oh at the alkaline electrode forming water that some are disposed at the alkaline electrode, and electrons that pass through the electrode forming a circuit, some of the water that wasn’t displaced would pass through a membrane and react with the O2 being fed and the electrons at the positive electrode that come from the first reaction and they would then form OH ions
what are the advantages of using a hydrogen-oxygen fuel cell
- they offer an alternative to the direct use of fossil fuels
- their products do not include carbon dioxide or pollutants such as carbon monoxide and oxides of nitrogen
- they are lighter and more efficient than engines that use fossil fuels
what is the disadvantages of using hydrogen-oxygen fuel cell
- hydrogen explodes easily when ignited so great care needs to be take to transport it
- the supply of hydrogen
what are the ways of transporting hydrogen and its disadvantages
- compressing the gas: transporting hydrogen under pressure is particularly hazardous
- absorbing hydrogen onto the surface of a suitable solid material: many metal absorb hydrogen, but so far there has not been a conclusion reached to which is best, but but carbon nanotubes is very promising.
- absorbing it into a suitable material: metal hydrides can absorb hydrogen, which can be released under correct conditions, the problem is that high temps are required
why is the supply of hydrogen a disadvantage for hydrogen-oxygen fuel cell
because most of hydrogen is produced from methane which is a limited source, it can be produced using renewable resources but the process is very expensive, our best option is wind-to-hydrogen plants, and using hydrolysis of water but they are being researched
