Investigation On The Al-Ga-In-Sn-X Alloys For Hydrogen Generation

Hydrogen energy has received widespread attention due to its high calorific value,sustainability,and environmental friendliness.However,hydrogen energy is a secondary energy,and the application of hydrogen relies on hydrogen production technology and hydrogen storage technology.Aluminum-water reaction for hydrogen production has attracted a wide spread attention due to its abilities to combine the production and storage of hydrogen,and realize on-demand and real-time hydrogen production.However,since a dense oxide layer is easily formed on the aluminum surface,this oxide film becomes the main obstacle to the production of hydrogen by the aluminum-water reaction.In order to produce hydrogen by the aluminum-water reaction,measures must be taken to destroy the oxide film.In this paper,we used Al and the low-melting-point metals（Ga,In and Sn）as raw materials,and added metal oxides（Al₂O₃,Bi₂O₃ and CaO）or inorganic salts（NaCl and KCl）as modifiers.Then the Al-Ga-In-Sn-Al₂O₃/Bi₂O₃/CaO alloys and the Al-Ga-In-Sn-NaCl/KCl alloys were prepared by mechanical ball milling method.Through a series of microstructure characterization and hydrogen generation experiments,the influence of alloy compositions,milling time and reaction conditions on the hydrogen generation properties of the alloys was studied.The main research contents and conclusions of this paper are as follows:1.Investigation on the Al-Ga-In-Sn-Al₂O₃/Bi₂O₃/CaO alloys for hydrogen generation（1）Compared with the Al-Ga-In-Sn-Al₂O₃/Bi₂O₃/CaO alloys,the hydrogen generation performance of the Al-Ga-In-Sn alloy is more affected by the milling time,and its hydrogen generation decreases with the extension of milling time from 1h to 3h;（2）The Al-Ga-In-Sn-Bi₂O₃ alloy has more defects on its particle surface,and it has the fastest hydrogen generation rate;（3）As the water temperature is 65°C,the hydrogen generation of the Al-Ga-In-Sn,Al-Ga-In-Sn-Bi₂O₃ and Al-Ga-In-Sn-CaO alloys all exceeds 1000 mL g^-1;（4）Reducing the alloy/water ratio can improve the hydrogen generation performance of all the alloys;（5）The air resistance properties of the Al-Ga-In-Sn-Al₂O₃/Bi₂O₃/CaO alloys is better than that of the Al-Ga-In-Sn alloy,and the Al-Ga-In-Sn-CaO alloy exhibits the best air resistance properties.2.Investigation on the Al-Ga-In-Sn-NaCl/KCl alloys for hydrogen generation（1）NaCl has a greater effect on increasing the hydrogen generation rate,while KCl has a greater effect on increasing the hydrogen yield;（2）The particle size of Al-Ga-In-Sn-NaCl alloys decreases with the increase of NaCl content,but the hydrogen generation performance increases first and then decreases with the increase of NaCl content;（3）Reducing the alloy/water ratio can improve the hydrogen generation performance of the Al-Ga-In-Sn-5%NaCl alloy.In addition,this alloy can realize better hydrogen generation performance in pure water than that in NaCl solution;（4）With the extension of milling time from 9h to 21h,the hydrogen generation properties of the Al-Ga-In-Sn-5%NaCl alloy increases first and then decreases.The 18 h milled Al-Ga-In-Sn-5%NaCl alloy achieves a hydrogen yield of 1150 mL g^-1 and reaches a hydrogen conversion yield of 95%in pure water at 25°C;（5）The Al-Ga-In-Sn-10%NaCl alloy has higher activation energy than the Al-Ga-In-Sn-5%NaCl alloy,and its reaction kinetics is more affected by the water temperature;（6）The Al-Ga-In-Sn-5%NaCl alloy and the Al-Ga-In-Sn-10%NaCl alloy exhibit different changes in hydrogen generation after being exposed in the air,and these two alloys can maintain100%and 94%of their original hydrogen yield after being placed in the air for 5 days and 10 days.