Mo-promoted spherical Co(OH)2 for enhanced hydrogen generation kinetics under alkaline conditions

In the context of hydrogen energy development, hydrogen production technology based on the hydrolysis of sodium borohydride (NaBH 4 ) has attracted considerable attention owing to its mild reaction conditions and the high-purity hydrogen generation. Nevertheless, the intrinsically sluggish hydrolysis kinetics of NaBH 4 require the development of non-noble metal catalysts that simultaneously achieve high catalytic activity and excellent durability. In this work, a molybdenum-doped cobalt hydroxide (MoO 2 -Co(OH) 2 ) catalyst was fabricated via a homogeneous urea precipitation approach, and its catalytic performance for H 2 generation from NaBH 4 hydrolysis was systematically evaluated. Concurrently, SEM, TEM, and XPS characterizations collectively elucidated the reaction pathway and electronic modulation mechanism involving Mo-doping-induced Co 2+ oxidation and oxygen vacancy generation. Additionally, this study demonstrates that the composite material possesses favorable surface hydrophilicity and exceptional synergistic catalytic activity. Through systematic modulation of the Mo/Co molar ratio, the MoO 2 -Co(OH) 2 catalyst achieved an exceptional hydrogen generation rate (HGR) of 9831.46 mL·min −1 ·g −1 at ambient temperature, concomitant with a markedly reduced activation energy (38.81 kJ·mol −1 ) relative to pristine Co(OH) 2 (68.97 kJ·mol −1 ). Furthermore, the catalytic performance of this system is comparable to, or even superior to, that of state-of-the-art Co-based catalysts. The superior catalytic performance was ascribed to the synergistic contributions of abundant defect sites afforded by the amorphous architecture, the intrinsically enhanced activity stemming from the electronic structure modulation, and the enhanced stability endowed by the compact microstructure.