Adsorption of hydrogen by palladium

In summary, hydrogen gas can be introduced into a piece of palladium metal in two ways: using a strong pump to put 900 times the volume of a gas cylinder into the cylinder, or by cooling the hydrogen beforehand. As the hydrogen enters the palladium, heat is released, which may be due to the formation of Pd-H bonds or the decrease in entropy. The volume of the gas decreases and so does its entropy.
  • #1
verdigris
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How does hydrogen gas get into a piece of palladium metal such that the amount of hydrogen is 900 times the volume of palladium?A strong pump would be required to put 900 times the volume of a gas cylinder into the cylinder or the hydrogen would have to have its temperature lowered first.
Heat is evolved as hydrogen goes into the palladium - is this the hydrogen being cooled or pd-h bonds forming?
 
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  • #2
I do not if there's any Pd-H bond formed when H2 comes into palladium, but part of the heat is due to the entropy following the term : T*deltaS.
Volume is reduced and so is entropy.
 
  • #3


The process of adsorption involves the physical attraction of gas molecules to the surface of a solid material, in this case, palladium. The high surface area of palladium allows for a large number of hydrogen molecules to be adsorbed, resulting in a high adsorption capacity. This means that for a given volume of palladium, a large amount of hydrogen gas can be adsorbed.

The mechanism by which hydrogen gas gets into the palladium metal is through diffusion. Hydrogen molecules, being small and highly mobile, can easily penetrate the surface of palladium and enter into the metal lattice. Once inside, they can form bonds with palladium atoms, resulting in the release of heat. This heat is a result of the exothermic process of bond formation between hydrogen and palladium.

To achieve an adsorption capacity of 900 times the volume of palladium, a strong pump would indeed be required to compress the hydrogen gas and force it into the metal. Alternatively, the temperature of the hydrogen gas could be lowered, reducing its volume and making it easier to adsorb into the palladium. However, this would also decrease the amount of heat released during the adsorption process.

In summary, the high adsorption capacity of palladium for hydrogen gas is due to its strong physical attraction to the gas molecules and the ability of hydrogen to easily penetrate its surface and form bonds with the metal atoms. The release of heat during this process is a result of the formation of pd-h bonds.
 

FAQ: Adsorption of hydrogen by palladium

1. What is adsorption and how does it differ from absorption?

Adsorption is the process of a substance (the adsorbate) adhering to the surface of another substance (the adsorbent). It differs from absorption, which is the process of a substance being taken in and retained by another substance. In adsorption, the adsorbate only adheres to the surface of the adsorbent, while in absorption, the substance is taken into the bulk of the other substance.

2. What is the role of palladium in the adsorption of hydrogen?

Palladium is a metal that has a high affinity for hydrogen, meaning that it can easily attract and hold hydrogen atoms on its surface through adsorption. This property makes it an ideal material for storing and transporting hydrogen gas, which is important for fuel cell technology and other applications.

3. What factors affect the adsorption of hydrogen by palladium?

The adsorption of hydrogen by palladium is affected by several factors, including temperature, pressure, and the size and surface area of the palladium particles. Higher temperatures and pressures can increase the amount of hydrogen adsorbed, while larger and more porous palladium particles can also increase the surface area available for adsorption.

4. How is the adsorption of hydrogen by palladium used in real-world applications?

The adsorption of hydrogen by palladium has several practical applications. One of the most significant is in fuel cell technology, where hydrogen is stored and then released from palladium during the electricity-generating process. It is also used in hydrogen purification, where palladium can separate hydrogen from other gases, and in hydrogen storage for use in transportation.

5. Are there any potential drawbacks or limitations to the adsorption of hydrogen by palladium?

While the adsorption of hydrogen by palladium has many benefits, there are also some potential limitations and drawbacks. For example, palladium is a relatively expensive metal, which can make it costly for large-scale applications. Additionally, prolonged exposure to hydrogen can cause degradation and damage to the palladium material, reducing its efficiency over time.

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