A Co-Fe/calcium phosphate catalyst improves the release of hydrogen from NaBH4

Abstract

In this study, catalysts for hydrogen release via either hydrolysis or methanolysis were developed with a focus on solid-state hydrogen storage. The catalyst and supports were produced and deposited concurrently during an electrochemical process. The goals of this study include the electrochemical syntheses of Co-Fe/calcium-phosphate catalysts and an assessment of their performance in the release of hydrogen during the hydrolysis and methanolysis of NaBH4. Catalyst synthesis was accomplished via an electrochemical method that uses an electrochemical cell with two chambers separated by a bipolar membrane. The catalyst particles are formed in the cathode chamber. The duration of electrolysis influences the calcium-phosphate phase. The pH is low at the beginning of electrolysis; brushite is formed. Hydroxyapatite is produced when the electrolyte solution is electrolyzed for a longer time, and the pH of the solution becomes high. The pH of the solution impacts both the calcium phosphate phase and the amount of metal catalyst in a solution. A higher metal catalyst content (Co and Fe) makes the hydrogen release rate more significant. Hydrogen was released at a rate of 7173 mL per minute per gram of Fe-Co during the hydrolysis reaction of NaBH4. Between 81,000 and 98,000 mL of hydrogen was produced per gram of Fe-Co each minute during the methanolysis reaction with NaBH4.