Photodecomposition of Anode/Cathode

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In summary, these reactions describe the oxidation and reduction of a compound semiconductor (MX) by photogenerated holes and electrons, respectively. The "z" in front of the electron indicates the change in oxidation state, while "solv" represents the solvent used in the reaction. The exact number of solvent molecules solvating the ion is not important, but it is necessary for the reaction to take place. This notation is not standard, but a convenient shortcut.
  • #1
citw
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Can some one explain (to a non-chemist) what exactly is happening in the decomposition reactions

[tex]
\text{MX}+zh^++\text{solv}\longrightarrow\text{M}^{z+}\cdot\text{solv}+\text{X}\text{ (oxidation) }
[/tex]

and

[tex]
\text{MX}+ze^-+\text{solv}\longrightarrow\text{M}+\text{X}^{z-}\cdot\text{solv} \text{ (reduction) }
[/tex]

In these reactions, MX referers to a compound semiconductor (e.g., M= Zn, Ga, Ti, etc., X=S, N, O2, etc.). It's my understanding that the first equation describes the oxidation of the semiconductor by its photogenerated holes, while the second describes the reduction by photogenerated electrons. This can be found in the following article

http://pubs.acs.org/doi/abs/10.1021/cm302533s

However, as I have limited education in chemistry, I don't really understand what is meant by the terms such as z in front of the electron, or "solv" indicated with the oxidized/reduced products. Are we saying "z electrons/holes", therefore changing the oxidation state by this amount? The "solv" part I really don't know about.
 
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  • #2
z is just a small integer number, solv means solvent/solvated.
 
  • #3
Borek said:
z is just a small integer number, solv means solvent/solvated.

So is it like I was saying, "z" electrons/holes?

What does it mean that "solv" appears as an individual reactant but is indicated next to (as?) one of the products?
 
  • #4
citw said:
So is it like I was saying, "z" electrons/holes?

Yes.

What does it mean that "solv" appears as an individual reactant but is indicated next to (as?) one of the products?

The way I read it you don't know how many molecules of solvent are used to solvate the ion, and it is not that important. What is important is that the reaction takes place in solvent and its molecules do solvate the produced ion.

It is not a standard notation, just a handy shortcut.
 
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  • #5


In simple terms, the photodecomposition of anode/cathode refers to the breakdown of a compound semiconductor (MX) into its constituent parts, M and X, through the use of light energy. This process involves the transfer of electrons (e^-) and holes (h^+) between the anode and cathode.

In the first equation, the compound semiconductor is oxidized by the photogenerated holes, which means that the holes remove electrons from the semiconductor, resulting in the formation of a positively charged M ion and a negatively charged X ion. The "z" in front of the h^+ refers to the number of electrons that are removed from the semiconductor.

In the second equation, the compound semiconductor is reduced by the photogenerated electrons, which means that the electrons are added back to the semiconductor, resulting in the formation of a neutral M atom and a negatively charged X ion. The "z" in front of the e^- refers to the number of electrons that are added to the semiconductor.

The "solv" in both equations refers to the solvent, which is the substance that the compound semiconductor is dissolved in. This is important because the solvent can affect the rate of the decomposition reactions.

Overall, the photodecomposition of anode/cathode involves the transfer of electrons and holes between the anode and cathode, resulting in the breakdown of the compound semiconductor into its constituent parts.
 

FAQ: Photodecomposition of Anode/Cathode

What is photodecomposition?

Photodecomposition is a chemical process in which a substance is broken down into smaller molecules or atoms due to exposure to light. It is a type of photochemical reaction.

How does photodecomposition occur in anode and cathode?

In anode and cathode, photodecomposition occurs when light energy is absorbed by the electrode materials, causing them to undergo a chemical reaction and break down into smaller components.

What factors influence the rate of photodecomposition in anode and cathode?

The rate of photodecomposition in anode and cathode can be influenced by factors such as the intensity of light, the wavelength of light, the surface area of the electrodes, and the chemical composition of the electrodes.

What are the potential applications of photodecomposition in anode and cathode?

Photodecomposition in anode and cathode has potential applications in fields such as renewable energy production, water purification, and chemical synthesis. It can also be used in the development of more efficient and durable electrode materials.

Are there any challenges or limitations associated with photodecomposition in anode and cathode?

Yes, there are some challenges and limitations associated with photodecomposition in anode and cathode. Some of these include the need for specialized materials that can withstand the harsh conditions of photochemical reactions, and the difficulty in controlling the rate of photodecomposition. Additionally, the byproducts of photodecomposition can sometimes be difficult to separate and purify.

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