دانلود رایگان مقاله انگلیسی نانوذرات Pd-Ni بر روی اکسید تیتانیوم به عنوان کاتالیزورهای موثر برای واکنش های اتصال - اشپرینگر 2017

Abstract

We have successfully prepared a series of PdNi/TiO2 catalysts by a one-step impregnation-reduction method. Among these catalysts with different compositions of Ni and Pd, the one with the Ni:Pd ratio of 2.95 showed the best activity. Small monodispersed Pd-Ni bimetallic nanoparticles were loaded on the surface of titanium oxide nanopowder as confirmed with TEM and EDS mapping. The XPS analysis demonstrated that Pd exists as 31% Pd(II) species and 69% Pd(0) species and all nickel is Ni(II). The prepared Pd-Ni/TiO2 exhibited enhanced catalytic activity compared to an equal amount of Pd/TiO2 for Suzuki-Miyaura reactions together with excellent applicability and reusability.

4 Conclusions

In summary, we have successfully developed a Pd-Ni/TiO2 catalyst for the SMRs through a one-step impregnationreduction method. TEM analysis showed that the spherical NPs dispersed uniformly on the TiO2 surface with a mean diameter of about two nanometers, which consisted of both Pd and Ni. The catalytic results show that the introduction of Ni to Pd improves the catalytic activities and the iodobenzenes and phenylboronic acids bearing with an electron-donating or electron-withdrawing group gave the corresponding product in excellent yields. Moreover, the Pd-Ni/TiO2 catalyst exhibited excellent stability and recyclability that no considerable loss in catalytic activities was observed after four cycles.