Preparation And Applications Of SiO₂/CdS Composite Nanoparticles

In the paper, the CdS/SiO2 composite nanoparticles that CdS discretely distributed in the surface of nano SiO2 particles were prepared, Also, its mechanism was discussed. Then the law of using the CdS/SiO2 composite nanoparticles as catalyst and emulsifiers applied in photolysis and Pickering emulsions were studied.The nano SiO2 particles were prepared using the St?ber method, whose size were affected by the factors such as silicon source of tetraethylorthsilicate (TEOS),the ammonia catalyst and the cosolvent of anhydrous ethanol, etc. The SiO2 particles were characterizated by Scan Electrical Microscope (SEM). Then the nano SiO2 particles were modified by CdS. Firstly, nano SiO2 was evenly dispersed in distilled water by ultrasound shock for several minutes, then added ammonia providing hydrolyzing condition of thioacetamide (TAA).The production of thioacetamide (TAA) hydrolyzed was acted with hydroxyl on the surface of SiO2.When CdSO4 solution was dropped into the solution, the empty orbit of Cd2+ ions and lone-pair electrons in N atoms were coalescent together, so that Cd2+ ion was pasted on the surface of SiO2 nano particles. At last, S2-ions of thioacetamide (TAA) hydrolyzed reacted with Cd2+ on the surface of SiO2 forming CdS/SiO2 composite nanoparticles. The optimal condition was concluded by lots of experiments with changing the temperature, pH and so on. CdS/SiO2 composite nano particles capped different quantity of CdS were prepared using a small amount but more times capped method. The photocatalytic degradation of methyl orange with different composite particles, different reaction time and different quantity CdS/SiO2 composite nanoparticles were experimentized, which indicated regular photocatalysis efficiency.CdS/SiO2 composite particles were prepared by a facile precipitation method, and the wettability of the obtained composite particles were investigated by a sedimentation test; The results showed that the hydrophobilicity of the CdS/SiO2 composite particles were increased with the increase of the amount of CdS, meanwhile the size of the drops and the amount of the obtained Pickering emulsions increased correspondingly. Through the way of polymerization, water and polystyrene concave interface and plane interface dispersed CdS/SiO2 composite particles were prepared and characterizated by Scan Electrical Microscope(SEM).The results indicated that with the hydrophobilicity of the CdS/SiO2 composite particles increased the particles more easily distributed on the concave interface. Meanwhile water-in-oil emulsions were obtained.