Youssef Essam

These are pretty basic questions that an RG search would help you with.

• Temperature is to ensure the formation of TiO2 from calcination of the intermediate Ti(OH)x where x is nominally 4
• Acidic pH is used to maintain the Ti in solution before precipitation with the appropriate base (often NH4OH but NaOH and KOH are often used). Study the Pourbaix diagram for the TiO2/H2O system to see what species are stable over what pH's. See attached diagram from the thesis mentioned below
• (PDF) Inorganic Synthesis Methods for Nanostructured Capacitors (researchgate.net)

Alan F Rawle Thank you. Is there any paper with more details on the recommended rpm and when to exactly stop mixing to save the integrity of the gel? because I can't find any good ones

Youssef Essam

There are many parameters to consider and rpm is generally irrelevant. Most important is the concentration of the reactants and then any subsequent treatments (e.g. spinning onto a substrate, drying and calcination stage including times and temperatures). The literature is full of methods and you'll need to find one that works for you.

Alan F Rawle During this run I used volumes which equal 0.1 mole of the primary precursors. Is this the reason why my gel broke up during mixing after synthesis? Will using a higher amount help? I am synthesizing a Cds doped titania silica nanocomposite with ttip and teos

Youssef Essam

Lower concentrations typically favor smaller sizes. Try 0.001 M as a diagnostic test. Reagents are relatively inexpensive.

Please find this attachment.

Dear Tiwari,

I understand your depth of feeling, I hope you read RA carefully.

Article Photocatalytic activity of N, Fe and Cu co-doped TiO2 nanopa...

Leshan Usgodaarachchi Mr. Usgidaarachchi, I actually did read your paper already and plan to use it as a guideline, but I have a few questions.

1) Did you not use a catalyst for hydrolysis?

2) I currently have no access to Deionized or double distilled water. Will Distilled water be ok?

3) What amounts of urea and metal salts should I use?

4) All other papers I read involved raising the temperature during synthesis. I might not be able to leave the sample stirring for 24 hours, so will raising the temperature to 60 C decrease the synthesis time?

Thanks

Youssef Essam

I guess TTIP is your Ti precursor, these answers are based in that hypothesis

1) I would recommend you work with the uncatalyzed hydrolysis process, during the catalyzed hydrolysis reaction nucleation growth takes place rapidly. Therefore, it may have a tendency to get agglomerated NP's

2) You can use distilled water, sometimes impurities may be detected during the characterization

3) It may depend on your purpose

4) Temperature is also one important factor in nucleation growth. If any reaction required activation energy to initiate reaction, only that kind of case use temperature increment to reach energy barrier. This reaction is not required temperature

*Stirring:- If you cant age your product by stirring. I would suggest your final product 20-30 min prior to the washing, drying and calcination steps

Leshan Usgodaarachchi

Thanks your answers are of great help.

As mentioned I probably can't let it age for 24 hours in mixing due to campus limitations, so i am forced to use catalyzed hydrolysis. I read that surfactants help counter the agglomeration process so i am using triton x-100

Regarding the purpose of synthesis, it is planned to synthesize several metal doped ceramic oxide nanocomposites as a layer for a DSSC. Any recommendations on the amounts of precursors, urea and metal dose to use? Because I haven't found any paper that mention the amount or yield of NPs from this process