Hydrolysis hydrogen production mechanism of Mg10Ni10Ce alloy surface modified by SnO2 nanotubes in different aqueous systems

(Mg-10wt%Ni)-10wt%Ce (Mg10Ni10Ce) was ball-milled with SnO2 nanotubes and Mg10Ni10Ce-xSnO(2) (x = 0, 5, 10 and 15 wt%) composites have been prepared. The phase compositions, microstructures, morphologies and hydrolysis H-2 generation performance in different aqueous systems (distilled water, tap water and simulated seawater) have been investigated and the corresponding hydrolysis mechanism of Mg10Ni10Ce and Mg10Ni10Ce-SnO2 has been proposed. Adding a small amount of SnO2 nanotubes can significantly enhance the hydrolysis reaction of Mg10Ni10Ce, especially the initial hydrolysis kinetics and the final H-2 generation yield. Unfortunately, the Mg10Ni10Ce-xSnO(2) hardly reacts with distilled water at room temperature. The hydrolysis reaction rate of Mg10Ni10Ce-5SnO(2) composite in tap water is still very slow with only 17.3% generation yield after 1 h at 303 K. Fortunately, in simulated seawater (3.5 wt% NaCl solution), the hydrolytic H-2 generation behavior of the Mg10Ni10Ce-5SnO(2) composite has been greatly improved, which can release as high as 468.6 mL g(-1) H-2 with about 60.9% generation yield within 30 s at 303 K. The Cl- destroys the passivation layer on MgeNieCe alloy surface and the added SnO2 nanotubes accelerate the hydrolysis reaction rate and enhance the H-2 generation yield. The Mg10Ni10Ce-5SnO(2) composite can rapidly generate a large amount of H-2 in simulated seawater in a short time, which is expected to be applied on portable H-2 generators in the future. (C) 2020, Institute of Process Engineering, Chinese Academy of Sciences. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

Automated summary

The study demonstrates that the Mg10Ni10Ce-SnO2 composite exhibits high hydrolytic H-2 generation performance in simulated seawater, with the addition of SnO2 nanotubes significantly enhancing the reaction rate. However, the low yield in distilled water and tap water indicates the significant influence of water quality on the hydrolysis reaction.