In-situ TEM heating of FeNiCr/C coatings for hydrogen evolution reaction
Jerzy Morgiel, Łukasz Maj, Tomasz Suszko, Małgorzata Pomorska, Ewa Dobruchowska, Witold Gulbiński
Quarterly No. 4, 2025 pages 243-251
DOI: https://doi.org/10.62753/ctp.2025.02.4.4
keywords: hydrogen evolution reaction, metal/carbon composites, coatings, in-situ heating
abstract The catalytic electrolysis of water enables this process to be performed at low over-potential, and therefore at a lower energy expenditure. Materials like Ni, Mo or W could substitute costly Pt in this role, especially when applied in the form of coatings. Experiments conducted to date have shown that the efficiency of electrolysis is still increasing in the case of metal nano-rods separated by carbon sheets. The present work is aimed at assessing the temperature stability of such a coating obtained by the magnetron sputtering of an AISI 316L (Fe69Cr18Ni11Mo2, in wt%) target in an atmosphere of Ar and C2H2. The use of in-situ TEM (transmission electron microscopy) heating allowed the start of crystallization of the so-produced coating to be determined, which occurred at ~400℃. Isothermal annealing at this temperature for 1 hour resulted in the predominant precipitation of -Fe in parallel with a smaller amount of Ni, Fe, C rich nano-particles, while Cr was distributed relatively uniformly throughout the whole coating. Simultaneously, the amorphous carbon underwent transformation to graphite. The experiment showed that the amorphous metal-carbon composite coatings developed for the hydrogen evolution reaction (HER) may be liable to crystallize in the case it was used in the catalytic electrolysis of superheated steam.