کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1283620 | 1497645 | 2008 | 6 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Effect of co-dopants on hydrogen desorption/absorption of HfCl4- and TiO2-doped NaAlH4 Effect of co-dopants on hydrogen desorption/absorption of HfCl4- and TiO2-doped NaAlH4](/preview/png/1283620.png)
The segregation of bulk Al after the hydrogen desorption may be one of many reasons why there is the incomplete hydrogen re-absorption and the need for higher desorption temperature in subsequent desorption of HfCl4- and TiO2-doped NaAlH4. In this work, we attempted to improve hydrogen storage capacity of 4 mol% HfCl4- and 4 mol% TiO2-doped NaAlH4 by adding a co-dopant (graphite, activated carbon, and MCM-41) using ball milling technique. It was found that the co-dopants significantly affect the hydrogen desorption/re-absorption of the hydride. Results show that the hydrogen re-absorption capacity of HfCl4- and TiO2-doped NaAlH4 added with the co-dopants increases 10–50% as compared with that without a co-dopant, and graphite seems to be the best co-dopant. Moreover, the hydrogen desorption temperature in the subsequent cycle of co-dopant doped samples decreases about 10–15 °C compared to the sample without a co-dopant. It could be explained that high porosity and large surface area of the co-dopants would decrease the segregation of bulk Al after the desorption and improve hydrogen diffusion in/out bulk of desorbed/re-absorbed samples.
Journal: International Journal of Hydrogen Energy - Volume 33, Issue 21, November 2008, Pages 6195–6200