Fizika Nizkikh Temperatur: Volume 46, Number 10 (October 2020), p. 1216-1226 ( to contents , go back )
Low-temperature sorption of hydrogen by porous carbon material containing palladium nanoclusters
А. V. Dolbin1, V. I. Dubinko2, N. A. Vinnikov1, V. B. Yeselson1, V. G. Gavrilko1, R. M. Basnukaeva1, M. V. Khlystyuk1, S. V. Cherednichenko1
V. O. Kotsyubinsky3, V. M. Boychuk3, and P. I. Kolkovsky3
1B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine Kharkiv 61103, Ukraine
2National Science Center Kharkov Institute of Physics and Technology, 1 Akademicheskaya Str., Kharkiv 61108, Ukraine
3Vasyl Stefanyk Precarpathian National University, 57 Shevchenko str. 76018 Ivano-Frankivsk, Ukraine
Received April 23, 2020, published online August 21, 2020
Sorption of hydrogen isotopes of composite nanostructured carbon material containing palladium clusters with an average size of 3–5 nm was studied in the temperature range of 8–290 K. It was shown that the total sorbed hydrogen highly depends on the method of producing the composite and accounts for 2–4.5 % of the mass of the sample. It was allocated two processes with characteristic times differing more than an order of magnitude in the kinetics of hydrogen sorption and desorption by a composite. The relatively fast process seems to be consistent filling hydrogen molecules in the cavities of the carbon matrix, and longer process — hydrogen diffusion into the crystal lattice of palladium nanoclusters. There were two temperature zones in the samples in temperature dependences of the diffusion coefficients of deuterium in composite: above 60 K, the activation energy diffusion in a sample containing palladium nanoclusters was more than two times higher values obtained for a pure carbon matrix. Below 60K diffusion coefficient of deuterium in a pure carbon matrix had practically no temperature dependences, while in the case of deuterium diffusion into palladium nano-clusters, the change the nature of the temperature dependence was observed at a lower temperature (~ 30 K), and below this temperature, the activation energy decreased about an order of magnitude.
Key words: low-temperature sorption of hydrogen isotopes, nanoclusters of paladium, sorption kinetics, diffusion coefficients.