H2 generation kinetics/thermodynamics and hydrolysis mechanism of high-performance La-doped Mg-Ni alloys in NaCl solution-A large-scale and quick strategy to get hydrogen

In this work, La-doped Mg-Ni multiphase alloys were prepared by resistance melting furnace (RMF) and then modified by high-energy ball milling (HEBM). The hydrolysis H-2 generation kinetics/thermodynamics of prepared alloys in NaCl solutions have been investigated with the help of nonlinear and linear fitting by Avrami-Erofeev and Arrhenius equations. Combining the microstructure information before and after hydrolysis and thermodynamics fitting results, the hydrolysis H-2 generation mechanism based on nucleation & growth has been elaborated. The final H-2 generation capacities of 0La, 5La, 10La and 15 La alloys are 677, 653, 641 and 770 mL.g(-1) H-2 in 240 min at 291 K, respectively. While, the final H-2 generation capacities of HEBM 0La, 5La, 10La and 15 La alloys are 632, 824, 611 and 653 mL.g(-1) H-2 in 20 min at 291 K, respectively. The as-cast 15La alloy and HEMB 5La alloy present the best H-2 production rates and final H-2 production capacities, especially the HEBM 5La can rapidly achieve high H-2 generation capacity (670 and 824 mL.g(-1) H-2) at low temperature (291 K) within short time (5 and 20 min). The difference between the H-2 generation capacities is mainly originated from the initial nucleation rate of Mg(OH)(2) and the subsequent processes affected by the microstructures and phase compositions of the hydrolysis alloys. Relative low initial nucleation rate and fully growth of Mg(OH)(2) nucleus are the premise of high H-2 generation capacity due to the hydrolysis H-2 generation process consisted by the nucleation, growth and contacting of Mg(OH)(2) nucleus. To utilization H-2 by designing solid state H-2 generators using optimized Mg-based alloys is expected to be a feasible H-2 generation strategy at the moment. (C) 2020 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.

Automated summary

La-doped Mg-Ni multiphase alloys modified by high-energy ball milling were investigated for hydrolysis H-2 generation kinetics/thermodynamics in NaCl solutions, showing that HEBM 5La alloy exhibits the best H-2 production rates and final H-2 production capacities.