Using a Catalyst With Fuel Cells: Benefits and Challenges

In summary, the conversation discusses the differences between galvanic cells and fuel cells, particularly in terms of the use of a catalyst and the desired state of equilibrium. The conversation also touches on the concept of maximizing power through balancing potential difference and reaction speed.
  • #1
Big-Daddy
343
1
With galvanic cells, we assume that the redox reaction is kinetically inhibited so that equilibrium takes a long time to reach, so we can make a good measurement of the potential difference V. I thought fuel cells were the same originally, except that we recycle in reactants and products to make sure that there's enough of each to maintain a high potential V, so that we produce power (equal to IV where I is the current).

But now I came across the idea of using a catalyst with the fuel cell. That just doesn't make sense to me. The more the reaction occurs, the closer the system will get to equilibrium where V=0 and thus the power output is 0, so why would we want that? OK, so we are cycling in new reactants anyway, so the reaction will never be at equilibrium - but still, why would we want to catalyse it? What's the benefit in that, when the power output is based specifically on potential difference (which is a function of how much of the reaction is still left to go at any given moment in time)?
 
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  • #2
Big-Daddy said:
the power output is based specifically on potential difference

No.

Apparently you still don't understand how the cell works and (hint) why do we have to close the circuit.
 
  • #3
Borek said:
No.

Apparently you still don't understand how the cell works and (hint) why do we have to close the circuit.

Ok, so is it because we have two conflicting interests - keeping a large potential difference V for which we need the reaction nowhere near to equilibrium, and getting the reaction to go reasonably fast so that we can get a decent current, I, out of it - and we maximize power (P=VI) by trying to make the reaction go fast (maximize I) and pumping in new reactants constantly (maximize V)? Or am I still not understanding?

The confusion was caused because my book said this was "just like the galvanic cell" except that reactants are pumped in continuously. I think this was slightly misleading because there is a crucial difference - in galvanic cells, we don't want current to flow (even though it is inevitable that a little does) because we want to measure V without the redox reaction getting any (significantly) closer to equilibrium.
 
  • #4
Big-Daddy said:
Ok, so is it because we have two conflicting interests - keeping a large potential difference V for which we need the reaction nowhere near to equilibrium, and getting the reaction to go reasonably fast so that we can get a decent current, I, out of it - and we maximize power (P=VI) by trying to make the reaction go fast (maximize I) and pumping in new reactants constantly (maximize V)?

That's it.
 
  • #5


I can explain the benefits and challenges of using a catalyst with fuel cells. First, let's understand the purpose of a catalyst in a fuel cell. A catalyst is a substance that speeds up a chemical reaction without being consumed in the process. In fuel cells, the catalyst is used to increase the rate of the redox reaction between the reactants (fuel and oxygen) to produce electricity.

Now, let's address the concern about the system reaching equilibrium and the power output being reduced. While it is true that the system will eventually reach equilibrium, the use of a catalyst ensures that the reaction occurs at a faster rate, allowing for a continuous flow of electricity. Without a catalyst, the reaction would occur at a slower rate and the power output would decrease over time.

Additionally, the use of a catalyst also allows for a more efficient use of reactants. As you mentioned, with galvanic cells, the reactants are not recycled and the potential difference decreases over time. However, with fuel cells, the reactants are continuously cycled in and out, and the use of a catalyst ensures that a higher percentage of the reactants are used in the reaction, resulting in a higher power output.

There are, however, some challenges associated with using a catalyst in fuel cells. One challenge is finding a suitable catalyst that is cost-effective, stable, and efficient. Another challenge is the potential for catalyst poisoning, where impurities or byproducts in the reactants can deactivate the catalyst and decrease its effectiveness.

In summary, the use of a catalyst in fuel cells offers several benefits, including faster reaction rates, increased efficiency, and continuous power output. However, there are also challenges that need to be addressed in order to effectively use a catalyst in fuel cells. Further research and development in this area will help to overcome these challenges and make fuel cells a more viable and sustainable source of energy.
 

1. What is a catalyst and how does it work with fuel cells?

A catalyst is a substance that increases the rate of a chemical reaction without being consumed in the process. In fuel cells, a catalyst helps to speed up the reaction between the fuel and the oxidizing agent, which produces electricity.

2. What are the benefits of using a catalyst with fuel cells?

There are several benefits to using a catalyst with fuel cells. One of the main benefits is that it allows for a more efficient conversion of fuel into electricity, resulting in higher energy output. Additionally, a catalyst can increase the lifespan of the fuel cell by reducing the likelihood of damaging side reactions.

3. What challenges are associated with using a catalyst in fuel cells?

One of the main challenges is finding the right catalyst for a specific type of fuel cell. Different fuel cells require different catalysts, and finding the optimal catalyst can be a time-consuming and expensive process. Another challenge is that some catalysts can be sensitive to impurities in the fuel, which can reduce their effectiveness.

4. Are there any environmental benefits to using a catalyst with fuel cells?

Yes, there are several environmental benefits to using a catalyst with fuel cells. Fuel cells produce electricity through a chemical reaction, rather than combustion, which means they do not emit harmful pollutants like carbon dioxide and nitrogen oxides. Additionally, using a catalyst can increase the efficiency of fuel cells, resulting in less fuel consumption and reduced emissions.

5. Is there ongoing research and development in the field of catalysts for fuel cells?

Yes, there is ongoing research and development in this field. Scientists are constantly working to improve the efficiency and effectiveness of catalysts for fuel cells. This includes developing new catalyst materials, as well as finding ways to reduce the cost and environmental impact of catalyst production.

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