High-efficient synthesis of NaBH4 by solid-phase electrolysis process on a core-shell-type cathode

NaBH 4 is a promising hydrogen storage material, while faced with enormous difficulties for scale-up application due to regeneration issues. In this study, a highly efficient and economical strategy for the electrosynthesis of NaBH 4 from hydrolysis by-product NaB(OH) 4 has been proposed. By fabricating solid-phase electrodes with NaB(OH) 4 and electrocatalyst etc., the mass transfer process of B(OH) 4 - at the cathode surface was remarkably improved, thus reducing the resistance of the cathodic reaction . Meanwhile, XPS , FTIR , and CV analyses were combined to reveal the reaction path and control steps of B(OH) 4 - reduction to BH 4 − in the electrocatalytic system . The formation of NaBH 4 and intermediates (BH(OH) 3 - , BH 2 (OH) 2 - , and BH 3 (OH) - ) is the gradual replacement of (OH) - in NaB(OH) 4 by H − . Furthermore, this study reveals that PbO has a suitable hydrogen evolution overpotential and excellent selective catalytic activity . The current efficiency for NaBH 4 synthesis via solid-phase electrolysis was up to 68.12 % by systematically regulating various factors.