空心纳米Ni@SiO_(2)复合材料的制备及其催化性能

Synthesis and catalytic activity of hollow nano Ni@SiO_(2) composites

分别在非离子表面活性剂聚醚L44、聚醚L64、壬基酚聚氧乙烯醚NP-7、脂肪醇聚氧乙烯醚AEO-7、曲拉通X-100和聚乙二醇十六烷基醚(Brij-58)与环己烷构成的反相微乳液体系中,从Ni(NO_(3))_(2)出发,经水合肼还原、正硅酸四乙酯水解包覆、焙烧、还原,得到不同结构的空心纳米SiO_(2)包覆镍(Ni@SiO_(2))复合材料。通过TEM、XRD表征材料结构和组成。结果显示,以聚醚L44、聚醚L64、NP-7、AEO-7和曲拉通X-100为模板时,制备出管状空心纳米Ni@SiO_(2);以Brij-58为模板剂时,制备出球形空心Ni@SiO_(2)-Brij-58。对空心Ni@SiO_(2)-Brij-58形成机理进行了研究。以催化NaBH_(4)还原对硝基苯酚为模型反应,研究了空心Ni@SiO_(2)-Brij-58的催化性能,结果表明,15 min内反应完全,对硝基苯酚转化率97.6%。

Nickel nitrate was added into the reverse micelle systems formed by cyclohexane and non-ionic surfactants polyether L44,polyether L64,nonyl phenol ethoxylate NP-7,alcohol polyoxyethylene ether AEO-7,Triton X-100 and polyethylene glycol hexanyl ether(Brij-58),respectively.And the above systems were reduced by hydrazine hydrate,coated by tetraethyl orthosilicate hydrolysis,roasted and reduced to give hollow nano SiO_(2) coated nickel(Ni@SiO_(2))composites with different structures.The as-synthesized products were characterized by TEM and XRD.The results showed that hollow spherical Ni@Si O_(2)composite(Ni@SiO_(2)-Brij-58)was obtained using Brij-58 as template and hollow tubular Ni@SiO_(2) composites were prepared using polyether L44,polyether L64,nonyl phenol ethoxylate NP-7,alcohol polyoxyethylene ether AEO-7 and Triton X-100 as templates.The formation mechanism of Ni@SiO_(2)-Brij-58 was also investigated.The reduction of p-nitrophenol in the presence of a catalytic amount of NaBH_(4) as model reaction was used to test the catalytic activity of Ni@SiO_(2)-Brij-58.It was found that the reaction was complete within 15 min,and the conversion rate of p-nitrophenol was 97.6%.