Enhancing hydrogen storage and production with an applied electric field

We propose a novel approach where an external electric field can be used not only to enhance hydrogen storage but also to produce hydrogen from hydrogen-rich molecular complexes. We chose BN sheet as an example, which has been synthesized experimentally. We find that in an applied electric field both hydrogen molecules behaving like electric dipoles and the electrons in BN sheet are polarized. The electrostatic interactions between hydrogen molecules and BN sheet greatly improve the storage performance. Once the applied electric field is removed, the stored H2 molecules can be released immediately, thus making the storage reversible. Contrary to the local electric field produced by exposed metal sites embedded in a substrate or matrix, external applied electric field is more effective and provides better control for reversible hydrogen storage. In particular, energetics and kinetics can be manipulated by tuning the field strength. Furthermore, the process avoids complicated synthesis routes for embedding metal ions and does not suffer from the possibility of clustering of these ions during repeated hydrogenation /dehydrogenation process. We also show that when an external electric field is applied to some hydrogen rich molecules such as BH3, AlH3, PH3, and SiH4, H atoms can be released, thus providing a way for producing hydrogen without any metal catalysts.