PEM electrolyzer - How does platinum reduce activation energy?

AI Thread Summary
The discussion centers on understanding how platinum affects the activation energy needed to dissociate water (H2O) in PEM electrolyzers. The original poster is seeking clarity on applying the Arrhenius equation to quantify this effect, providing specific operating specifications for a PEM electrolyzer, including input voltage, current, and hydrogen and oxygen production rates. They also reference a previous post regarding volumetric flow rates and the mass of water involved in the electrolysis process. A key point of contention arises around the role of platinum; while one comment asserts that platinum does not reduce activation energy and is primarily used for its oxidation resistance, another counters that platinum black has catalytic properties that lower activation energy, enabling more efficient electrolysis with reduced overpotential. The discussion highlights the complexity of platinum's role in electrolysis and the need for a deeper mathematical understanding of these processes.
HelloCthulhu
Messages
150
Reaction score
3
I've been researching pem electrolyzers, but still don't understand how to mathematically express how platinum reduces the activation energy necessary to dissociate H2O. I've seen the Arrhenius equation solved before, but didn't understand how to get the values for it. Here are the operating specs for the electrolyzer:

https://www.fuelcellstore.com/manuals/horizon-mini-pem-electrolyzer-instructions-fcsu-010.pdf

- Input Voltage: 1.8V ~ 3V (D. C.)

- Input Current: 0.7A

- Hydrogen production rate: 7ml per minute at 1A

- Oxygen production rate: 3.5ml per minute at 1A

In a previous post, I tried to figure out what the volumetric flowrate would be. Not sure if the mass is necessary to find the activation energy, but I'll include it anyway:

https://www.physicsforums.com/threads/amount-of-water-electrolyzed-during-pem-electrolysis.992823/

2H2O —> 2H2 + O2

3.5 ml O2/min = 0.00015625 M O2(STP)

0.0003125 H2O(l) →0.0003125 H2(g)/1A*min + 0.00015625O2(g)/1A*min
0.0003125M H2O *18 g = 0.005625 g/1A*min H2O

Any help is greatly appreciated!
 
Chemistry news on Phys.org
Platinum does not reduce activation energy it is only used for electrodes because it resists oxidation better then other materials.
 
Miloje said:
Platinum does not reduce activation energy it is only used for electrodes because it resists oxidation better then other materials.

It is not that simple - platinum black has some catalytic properties which make it perfect for electrode material, as when used most processes work with lower overpotential. And - as it is a case with catalysis - it works by lowering activation energy.
 
  • Like
Likes HelloCthulhu and Astronuc
I want to test a humidity sensor with one or more saturated salt solutions. The table salt that I have on hand contains one of two anticaking agents, calcium silicate or sodium aluminosilicate. Will the presence of either of these additives (or iodine for that matter) significantly affect the equilibrium humidity? I searched and all the how-to-do-it guides did not address this question. One research paper I found reported that at 1.5% w/w calcium silicate increased the deliquescent point by...
I was introduced to the Octet Rule recently and make me wonder, why does 8 valence electrons or a full p orbital always make an element inert? What is so special with a full p orbital? Like take Calcium for an example, its outer orbital is filled but its only the s orbital thats filled so its still reactive not so much as the Alkaline metals but still pretty reactive. Can someone explain it to me? Thanks!!
I'm trying to find a cheap DIY method to etch holes of various shapes through 0.3mm Aluminium sheet using 5-10% Sodium Hydroxide. The idea is to apply a resist to the Aluminium then selectively ablate it off using a diode laser cutter and then dissolve away the Aluminium using Sodium Hydroxide. By cheap I mean resists costing say £20 in small quantities. The Internet has suggested various resists to try including... Enamel paint (only survived seconds in the NaOH!) Acrylic paint (only...

Similar threads

Replies
26
Views
5K
Back
Top