Hi everyone
For ZnS - GO synthesize, at first the synthesized GO was mixed with zinc acetate dehydrate which was earlier dissolved in DI water. Then the solution pH was adjusted to 9 by adding ammonia solution. Subsequently, in the above mixture of sodium sulfide dissolved in DI water was added. After ultrasonicating the mixture it was transferred into a autoclave. The prepared mixture was kept in a sealed autoclave at 140 oC for 8 h which yielded a black (gray) composite. The product was further washed and then dried at 120 oC for 24 h. Unfortunately in XRD patterns, results only demonstrate the ZnO-GO nanocomposite structure instead of ZnS-GO nanocomposite.
Can anybody improve our method to reach ZnS-GO?
Hi Monir Niazi
More intense peaks in XRD generally denote the better phase formation of the products. Please tally the results with standard JCPDS data files. You may use a vacuum oven to dry which may give better results. Please do the XRD calculation of the products to check the unit cell nature also. You can change the reaction time in the hydrothermal chamber to check the effect. This I can suggest from my side.
Regards
Hi Dear,
You need the check the amount of sulfur precursor, because sulfur is volatile in nature. if stirring is held at a temperature higher than room temperature, this may be the reason. My suggestion is to increase the concentration of sulfur precursor.
What is quantum confinement, and how is it related to the borh radius of each compound (semiconductor)?
Waiting attentively for your help, I remain from you
Regards.
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Dear Monir,
a possible reason why you isolated only the ZnO-GO nanocomposite instead of the desired ZnS-GO nanocomposite could be that air oxidation of your ZnS-GO product has taken place. As an alternative route you can try the method outlined for ZnS NPs@RGO in the article cited below. In this study, the authors avoid the step of heating the product in an autoclave. Instead, after ultrasonication the ZnS NPs/RGO nanocomposite is calcinated directly:
Layered nanocomposite of zinc sulfide covered reduced graphene oxide and their implications for electrocatalytic applications
Article Layered Nanocomposite of Zinc Sulfide Covered Reduced Graphe...
Also please have a look at the following potentially useful article:
Sonochemical synthesis of reduced graphene oxide uniformly decorated with hierarchical ZnS nanospheres and its enhanced photocatalytic activities
Article Sonochemical synthesis of reduced graphene oxide uniformly d...
This paper describes an alternative route which involves simple ultrasonic irradiation of aqueous solutions of zinc acetate dihydrate, thioacetamide, and GO.
The second article is freely available as public full text, while you can request the full text of the first paper directly from the authors via RG (all four authors have RG profiles).
Good luck with your work!
Monir Niazi
My suggestion is you may increase the amount of Na2S (i.e. in mole) with respect to Zn precursor (in mole). You will get ZnS/rGO. Better to use 1:5 ratio (Zn salt: Na2S) or above. To get high pure (i.e. to remove "Na"), repeated washing of final product is important. Meantime read some published papers!..
It is better to add Na2S before the addition of NH3 solution, and allow them to form ZnS. (i.e. addition of NH3 should need to be last; which will initiate the co-precipitation)
In your case, MAY BE, instead of ZnS/rGO formation, it could be ZnO/S-doped rGO !..
From my view, the formation of ZnO/rGO, is "Then the solution pH was adjusted to 9 by adding ammonia solution. Subsequently, in the above mixture of sodium sulfide dissolved in DI water was added." THIS MEANS, you have added Na2S, after ZnO/Zn(OH) precipitations initiated.
Hence, it obvious that, the S could be doped in rGO instead of ZnS formation.
Hope this tips may be useful..
Regards
Chandru
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