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

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.