An one-step approach towards hydrogen production and storage through regeneration of NaBH4

Abstract

The hydrolysis of NaBH4 offers significant advantages for hydrogen storage in fuel cells, whereby suffers from the irreversibility. Thus, a simple and low cost method for NaBH4 regeneration from its hydrolysis byproduct is crucial. Herein, we describe a single step method for NaBH4 regeneration, which combines both hydrogen production and storage in the one step. In the process, a mixture of magnesium silicide and dihydrate sodium metaborate is reacted via ball milling under ambient conditions without the requirements of additional hydrogen sources. The hydrogen only comes from the splitting of H2O in the NaBO2·2H2O that is a direct byproduct of NaBH4 hydrolysis. The purified product demonstrates the same physicochemical properties as commercial NaBH4. Yields for NaBH4 regeneration approaching 80% are achieved using this method. Mechanism study indicates that the high yield is likely to be beneficial from the formation of the Mg-O-Si-H conjugated structure. NaBH4 regeneration using this process demonstrates a 30-fold reduction in cost over a previous study that used MgH2 as the reduction agent.