Porous Ni-Co surface formation and analysis of hydrogen generation by gas sensor

A NieCo alloy was used as the test piece. The porous NieCo alloy surface was prepared by Al electrodeposition at -1.4 V and -1.8 V and Al dissolution at -0.5 V in a NaCl-KCl-3.5 mol% AlF3 molten salt. The bath temperature was 750 degrees C and 900 degrees C. As a result, a porous NieCo alloy could be prepared by Al electrodeposition and Al dissolution on the Ni-Co alloy in the molten salt. It was clarified that a denser surface was formed at the bath temperature of 750 degrees C than at the bath temperature of 900 degrees C. Furthermore, it was clarified that the porous layer became thicker when the electrodeposition potential was -1.8 V than when it was - 1.4 V. The formed porous NieCo alloy was evaluated for cathode performance in a 10 mass% KOH solution. Furthermore, the amount of generated hydrogen was measured by a constant voltage and constant current test with a gas sensor using a solid electrolyte. In the cathode polarization curve, the porous NieCo alloy showed a higher current density at a lower potential than the untreated NieCo alloy. It was shown that the NieCo alloy formed under the electrodeposition conditions at the electrodeposition potential of similar to 1.4 V and bath temperature of 750 degrees C is a very excellent cathode material. Furthermore, based on the constant voltage test, it was revealed that the porous treated sample generates a higher amount of hydrogen than the untreated sample. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.