Synthesis and Characterization of Copper-based Electrocatalysts for Alkaline Hydrogen Evolution and Oxidation

Abstract

In this study, copper nanoparticles were synthesized, and later introduced to a small amount of cobalt, in order to compare activities for the hydrogen evolution and oxidation reactions pertinent to the solar-to-hydrogen energy conversion process. Electrochemical tests shows that cobalt-treated copper nanowires were less active and stable for HER and HOR than were copper nanowires. This trend in activity may be attributed to a loss of crystallinity in the sample. TEM confirmed this decrease in crystallinity, while SEM showed that copper nanowires became rougher, shorter, and thicker after cobalt treatment. Additionally, TEM and XPS confirmed the presence of an outer oxide layer on the nanowires, which affected HER/HOR activity as oxygen reduction also occurred. Further efforts should be made to prevent samples from oxidizing, to incorporate cobalt into copper nanowires without a loss in crystallinity, and to completely remove oxygen from the electrochemical cell.