Additional accelerated service life test for testing Ni-Sn coatings under the conditions of industrial hydrogen production

Abstract

The accelerated service life test (ASLT), developed by PERMASCAND and applied in a specially designed flow cell, is presented for the first time in the literature in this work. This test involves the application of six sequences of very high current densities, followed by zero current density, in 5.0 M NaOH at 50 ^oC. The test is performed on Ni-Sn coatings electrodeposited onto Ni mesh, which serves as the substrate for catalytic coatings used by PERMASCAND. The results demonstrate that the overpotential (h) for hydrogen evolution reaction (HER) on several Ni-Sn samples is practically unaffected by the test sequences, remaining approximately -180 mV at j = -1000 mA cm^-2. The same test was applied to PERMASCAND’s commercial cathodes, and the results were compared. Additionally, the Ni-Sn samples were tested in a stationary electrolyte H-cell configuration using polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Nyquist plots recorded at four different values of h were characterize <d by the presence of two semi-circles, indicating the presence of charge transfer reaction and intermediate adsorption reaction. Comparing polarization curves recorded in PERMASCAND’s test cell after the ASLT and in the stationary H-cell after the EIS measurements suggests that long-term performance should be assessed using the ASLT developed by the industry.