کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
191908 | 459731 | 2009 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: On the role of the thermal treatment of sulfided Rh/CNT catalysts applied in the oxygen reduction reaction On the role of the thermal treatment of sulfided Rh/CNT catalysts applied in the oxygen reduction reaction](/preview/png/191908.png)
Low loading sulfided rhodium catalysts supported on carbon nanotubes (CNTs) were prepared from RhCl3 by deposition–precipitation using hydrogen peroxide, followed by an exposure to hydrogen sulfide and an additional thermal treatment in the range from 400 °C to 900 °C. Hydrogen sulfide was generated online from hydrogen and sulfur vapor over molybdenum disulfide as catalyst. By elemental analysis, the Rh loading of the prepared catalysts was found to be 1.4–1.8 wt%. Morphology and composition of the resulting catalysts were characterized by X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM), and X-ray photoelectron spectroscopy (XPS). Nanoparticles were found to be highly dispersed on the CNTs with an average diameter as small as 1.0 nm determined by TEM. Sintering occurred during heat treatments at 650 °C and 900 °C in helium, as evidenced by XRD, TEM, and XPS. The treatment with hydrogen sulfide significantly enhanced the activity of the supported rhodium catalysts for the oxygen reduction reaction (ORR) in hydrochloric acid, as determined by rotating disc electrode measurements. The sulfided catalyst annealed at 650 °C with a particle size of about 2.5 ± 1.0 nm showed the best performance for the ORR, which is discussed based on the presence of a more stable rhodium sulfide layer on the metallic rhodium particles.
Journal: Electrochimica Acta - Volume 54, Issue 28, 1 December 2009, Pages 7186–7193