Hafnium-an optical hydrogen sensor spanning six orders in pressure.

ABSTRACT: Hydrogen detection is essential for its implementation as an energy vector. So far, palladium is considered to be the most effective hydrogen sensing material. Here we show that palladium-capped hafnium thin films show a highly reproducible change in optical transmission in response to a hydrogen exposure ranging over six orders of magnitude in pressure. The optical signal is hysteresis-free within this range, which includes a transition between two structural phases. A temperature change results in a uniform shift of the optical signal. This, to our knowledge unique, feature facilitates the sensor calibration and suggests a constant hydrogenation enthalpy. In addition, it suggests an anomalously steep increase of the entropy with the hydrogen/metal ratio that cannot be explained on the ba

SUBMITTER: Boelsma C 

PROVIDER: S-EPMC5465374 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature