Highly active cobalt-based catalysts in situ prepared from CoX2 (X = Cl−, NO3−) and used for promoting hydrogen generation from NaBH4 solution

Two kinds of CoX2 (X = Cl−, NO3−) are adopted as the accelerators for the hydrolysis reaction of NaBH4, which is a promising H2-supply method for proton exchange membrane fuel cell (PEMFC). In the reactor, the initial H2 generation is caused by the reaction between pre-infused CoX2 solution and subsequently imported NaBH4 solution, and some precipitates are in situ formed on the catalyst bed by this way; and the following H2 generation is promoted by these precipitates. It is found that there are competitive reactions during H2 generation from an NaBH4 to NaOH solution, the anions of CoX2 are crucial to the reaction pathways, which led to the formation of highly active Co–B or inactive Co(OH)2. The effects of the CoX2 concentration, the NaOH concentration, the NaBH4 feeding rate and the NaBH4 concentration on H2 generation performances are discussed and compared.