The Activation Of Aluminum Powder Surface And Its Hydrogen Production Performance

There are two major problems in the world today:environmental pollution and energy crisis.The development of new energy industries is the key to solving environmental pollution and energy crisis.Hydrogen,as a well-known secondary energy source,has attracted people's extensive attention due to its environmental friendliness and high energy.At present,the vigorous development and utilization of hydrogen energy are the major ways to solve energy problem.Among the common hydrogen production materials,aluminum-based hydrogen production materials have unique advantages.As a light metal,aluminum is cheaper and has a large crust content.And compared with other metal-based hydrogen production materials,the hydrogen production of aluminum-based hydrogen production materials is more,and the hydrogen storage density is higher.This is a major advantage of aluminum-based hydrogen production materials.However,due to the oxidation nature of elemental aluminum,it makes it easy for oxygen to react with Al and is oxidized to aluminum oxide coating on the surface of aluminum powder to form an inert layer.Alumina is relatively stable and can block the contact between the internal elemental aluminum and external water.Destroying the aluminum oxide inert film can increase the reactivity of aluminum powder with water.In this paper,two kinds of inorganic salts BiCl₃ and SnCl₂ are added to act as activators of aluminum powder to increase the activity of aluminum.The prepared materials are Al-BiCl₃ composites and Al-SnCl₂ composites.The studies on the two materials are as follows:?1?Preparation of Al-BiCl₃ composite hydrolyzed hydrogen production materials.The planetary mechanical ball mill is used during the experiment.The ball milling is under the air environment without other grinding aids,which can reduce the requirements for experimental equipment to a certain extent,saves energy,and reduces production costs.By adding BiCl₃ to aluminum powder,the activity of aluminum powder can be effectively increased,and the conversion rate of the reaction of aluminum with water can be improved.The highest conversion rate is 98.58%,and the hydrogen production amount is 1198mL/g.Through a series of explorations,it is learned that aluminum and the active additive BiCl₃ have a substitution reaction through the ball mill contact during the ball-milling to produce elemental niobium and then to increase the activity of aluminum.Through the exploration of the ball milling time,it is found that an appropriate increase in the time of the ball milling reaction contributes to the enhancement of the activity of the aluminum powder,and a long ball milling time is not conducive to increase the activity of the aluminum.When the milling time is 5 hours,the conversion rate of aluminum powder is 98.58%at the highest.Through investigation of the additive amount of active additives,the optimum active additive content of Al-BiCl₃ composite is 10%.It is helpful for the aluminum powder to become smaller in particle size.But too much addition is not conducive to the activity of the aluminum powder.Finally,25?m aluminum powder is experimentally compared with 100 mesh²00 mesh?75?m¹50?m?aluminum powder.Under the same experimental conditions,the composite material obtained by the smaller particle size aluminum powder has higher reactivity,and the smaller the particle size,the greater its activity and the easier it is to activate and modify it.?2?Preparation of Al-SnCl₂ compound hydrolyzed hydrogen production materials.By adding active additive SnCl₂ to aluminum powder can effectively increase the activity of aluminum powder,increase the conversion rate of aluminum and water reaction,the highest conversion rate is 96.91%,hydrogen production capacity At 1034mL/g,the hydrogen production per gram of composite material was9.23g,which reached a very high level of hydrogen production.After a series of investigations on the experimental mechanism,it was learned that aluminum and the active additive SnCl₂ were replaced by ball-milling during the ball-milling reaction to generate elemental tin to achieve the effect of activating aluminum.In addition,through the exploration of ball milling time,it is found that increasing the time of the ball milling reaction is conducive to the enhancement of the activity of aluminum powder.If the ball milling time is too long,the activity of aluminum powder is not increased,and the agglomeration of the material may be affected.The activity of the material reduces its final conversion and the ball milling time is best for 5 hours.Through a study of the amount of active additive,it was determined that the optimal active additive mass fraction of Al-SnCl₂ composite is 20%.And the increase of active additive contributes to the smaller particle size of aluminum powder,but the excessive addition amount is not conducive to the enhancement of aluminum powder activity.