Monopulse electrodeposited nanoflower-like Co-Mo-P/Cu catalyst for efficient hydrogen production from hydrolysis of sodium borohydride: Synergistic mechanism and electrochemical reactivation

Abstract

High-performance catalysts for hydrogen generation from sodium borohydride (NaBH 4 ) hydrolysis are pivotal for portable energy applications. In this work, a hierarchical Co-Mo-P/Cu catalyst with spherical nanoflower structure was synthesized via a facile one-step monopulse flow electrodeposition method. The as-prepared catalyst exhibits exceptional catalytic activity, achieving a high hydrogen generation rate (HGR) achieved 15.5 L min −1 ·g −1 cat at 50 °C with a remarkably activation energy (E a ) of 42.16 kJ mol −1 . Density Functional Theory (DFT) calculations elucidate that the synergistic effect of Co, Mo and P optimizes the adsorption of H atoms and significantly lowers the energy barrier for the rate-determining dehydrogenation step (NaBH 3 to NaBH 2 ). Mechanism analysis further reveals that the formation of *NaBOH intermediates is energetically more favorable than *NaOBH due to the easier cleavage of B-H bonds over H-O bonds. To address the activity decay caused by NaBO 2 accumulation on the active sites, an innovative electrochemical reactivation strategy was developed. This approach effectively recovers the catalyst's surface active sites through the electroreduction NaBO 2 , substantially extending its operational lifespan. This work provides a new perspective on designing highly active and regenerable transition metal catalysts for efficient hydrogen storage.