Catalysts for the hydrolysis of aqueous borohydride solutions to produce hydrogen for PEM fuel cells

Abstract

The objective of the present study was to understand the superior catalytic performance of PtRu-LiCoO2 catalyst for hydrogen (H2) generation from aqueous sodium borohydride (NaBH4) solutions by comparing the catalytic activity of various PtRu-supported catalysts. Three of the support materials namely cobalt oxide (Co3O4), lithium nickel oxide (LiNiO2) and lithium manganese oxide (LiMnO2) were synthesized and characterized using XRD. The PtRu-supported catalysts with eight different support materials were prepared and characterized using XRD and BET surface area measurements. The results revealed excellent hydrogen generation activity of Co3O4 and LiCoO2 for the hydrolysis of NaBH4. Actually, the catalytic activity of Co3O4 and LiCoO2 is due to the formation of cobalt boride (CoB) by the reduction of these oxides by NaBH4. A model is proposed to explain the hydrogen generation profile of the above catalysts. The CoB formation is confirmed by XPS studies. Further, the performance of Co3O4 and LiCoO2 was compared with various noble metal catalysts. The performance of Co3O4 is at par with the noble metal based catalysts at low concentration of NaBH4 and far superior to noble metal based catalysts at higher concentration.