In our recent work [1], we report an operando X-ray absorption spectroscopy study of a microheater catalytic hydrogen sensor based on anodic alumina with a Pd : Pt molar ratio of 3 : 1 in the catalyst. When the sensor operates in air, palladium oxidation blocks hydrogen combustion. Only after the reduction of PdO to metallic Pd in presence of hydrogen at 38 °C, the hydrogen catalytic oxidation manifests itself as a sharp increase in sensor response from 0 to 15 mV/vol% H2. The observed feature is important for detecting low hydrogen concentration with no response lag, decreasing the operating temperature of the sensor, and measuring in pulsed mode.
This research was funded by the Russian Science Foundation (grant No. 25-13-00417) and the Ministry of Science and Higher Education of the Russian Federation (grant No. 075-15-2025-608).
[1] I.A. Kalinin, I.V. Roslyakov, I.V. Kolesnik, E.V. Khramov, D.N. Khmelenin, K.S. Napolskii, Microheater-based catalytic hydrogen sensor: Operando X-ray absorption spectroscopy study of Pd–Pt catalyst chemistry // International Journal of Hydrogen Energy, 2025, v. 179, 151472. DOI: 10.1016/j.ijhydene.2025.151472.