Rapid catalytic hydrolysis performance of Mg alloy enhanced by MoS2 auxiliary mass transfer

Abstract

Mg10Ni-MoS2 composites were synthesized, and the amount of molybdenum disulfide (MoS2) and ball milling time was optimized to obtain rapid initial kinetics with high conversion yield at room temperature in simulated seawater. The microstructures and H2 generation thermodynamics were comprehensively investigated to demonstrate the main influential factors on excellent initial hydrolysis performance. Mg10Ni-5 wt%MoS2-15 min can generate 493.3 mL·g-1 H2 at 298 K with 58% yield in 20 s. The H2 generation capabilities of Mg10Ni-5 wt% MoS2-15 min are 569 mL·g-1 H2 and 67%, which are higher than those of Mg10Ni (495 mL·g-1 H2, 56%) in 2 min. The lowest hydrolysis activation energy (18.74 kJ·mol-1) can be achieved by Mg10Ni-5 wt%MoS2, which means low energy consumption. Mg10Ni with higher specific surface area (4.04 m2⋅g-1) than that of Mg10Ni-5wt.%MoS2-15 min (0.78 m2⋅g-1) presents worse H2 generation performance, indicating that higher specific surface area is the secondary determinant for superior initial hydrolysis kinetics and higher conversion yield compared with the added MoS2. The added MoS2 with specific morphologic structure can provide auxiliary mass transfer paths, which shorten the transfer distance and destroy the continuous colloidal layer. Mg-rich alloys optimized for rapid and efficient H2 production performance are expected to be applied large-scale H2 generators.