Dear Toru,

Before I can really help you I need to know what kind of solvent you have used and what were the synthesis conditions (pressure, temperature, duration and so on). For the moment, I want to point out that ZrO2 is extremely stable and is regarded as the thermodynamic end product in zirconia chemistry. So you have to avoid any humidity....Hope this helps a bit!

All the best,

Thomas

Dear Thomas Jüstel

Thank you for your reply. The synthesis conditions are as follows. The difference from the literature is that it is slightly scaled up and does not use a centrifuge.

Oleylamine (Wako Pure Chemical, total amine number (KOHmg/g): 200.0-216.0) was dehydrated with molecular sieves (0.3 nm). Zirconium (IV) chloride (sigma-aldrich, anhydrous, powder, 99.99% trace metals basis) (0.47g, 2.0 mmol) and oleylamine (17mL, 51.2 mmol) are added to a 100mL three neck round bottom flask under N2 atmosphere. The mixtures are evacuated for 10 minutes. After purging with N2, the reaction mixture is first heated to 300 ℃ at the heating rate 5 ℃/min. When reaction temperature reaches at 300 ℃, CS2 (0.8mL, 13.7 mmol) is injected into the reaction mixture. After 3 hour, the reaction is stopped and cooled down to room temperature by removing heating source. By addition of excess butanol(40mL), the crudes are allowed to stand still and the solids were precipitated. The solids are filtered through a suction bottle and washed with hexane and methanol. It was found that Sulfur and ZrO2 were obtained from the XRD results.

Any advice you can give me would be very helpful.

Toru.

Toru Inatome The boiling point of carbon disulfide is 43.6 C. Therefore, carbon disulfide must be added after adding zirconium chloride. You have it evaporated. You must synthesize in a reflux flask so that the carbon disulfide does not evaporate. You got zirconium oxide due to the fact that you did not supply nitrogen to the reaction mixture during the synthesis. A constant supply of nitrogen is required.

Dear Toru,

Prof. Mirgorod is right. Moreover, you have to keep all components including the glass ware extremely dry to prevent hydrolysis. The formation of elementary sulphur points to the reduction of S2- which might be promoted by butanol.Please check the patent US 7,078,005 B2.

All the best,

Thomas

Dear Prof. Yuri Mirgorod and Prof. Thomas Jüstel :

Thank you very much for your advice. Also, thank you for providing me with useful patent references. I was not very familiar with the role of butanol, so this has helped me a lot.

I believe that the method of sulfidation is not wrong, as I was able to synthesize ZnS nanoparticles by hot injection of CS2 at 300°C, as per the literature. The reflux tube is also connected. It is conceivable that the N2 atmosphere may not be perfect, as Prof. Mirgorod said, that ZrO2 can nevertheless be made. I will experiment again with thorough drying of the synthesis equipment.

I am also considering other causes, such as the effect of the raw material ZrCl4 being very hygroscopic and the effect of the oleylamine not being distilled.

If you have any reference material to help me out, it would be very helpful.

Toru