Improvement Of Service Life Of Ferrite Catalyst For Hydrogen Production And Lower Temperature Of Reaction

The demand for energy in modern society is getting higher,traditional energy sources are increasingly depleted,and the massive burning of fossil fuels has caused serious environmental problems.The development and the use of pollution-free green energy has become an important issue that human beings must solve in order to achieve sustainable development.At the same time,the excessively high reduction temperature has strict requirements on the heat collection capacity and heat resistance of the photothermal equipment,which hinders the application of ferrite catalytic thermal cracking water to produce hydrogen.This article attempts to improve the production of hydrogen by catalytically pyrolyzing water from ferrite in terms of inhibiting ferrite sintering and reducing the reduction temperature of ferrite.The following investigations were conducted:Hydrogen energy has attracted wide attention due to its pollution-free and high energy density.If it can solve the clean manufacturing and safe use of hydrogen,it may become the ultimate form of clean energy.Hydrogen producted by the pyrolysis of ferric oxide and other polyvalent oxides is one of the main methods of generating hydrogen using solar heat.At present,the main problem is that the specific surface area caused by sintering of oxides during thermal cycling decreases,resulting in a decrease in hydrogen production capacity.In addition,the heating temperature that the photothermal equipment can provide is limited,and the reduction temperature of the ferrite is too high and the temperature supplied by the photothermal equipment does not match.It is necessary to reduce the reduction temperature of the ferrite catalytic thermal cracking to produce hydrogen.This article explores the following from the perspective of suppressing ferrite sintering and reducing the reduction temperature of ferrite:?1?The first part is study on the effect of zirconia doping on the hydrogen production catalyzed by ferrite.The nickel ferrite and manganese ferrite were tested in multiple thermochemical cycles of hydrolysis to produce hydrogen.The experiments found that nickel ferrite has a stronger hydrogen production capacity than manganese ferrite in multiple thermochemical cycles.At the same time,as the number of cycles increases,both nickel ferrite and manganese ferrite powders are sintered,the specific surface area is gradually reduced,the hydrogen production capacity of the material is gradually reduced,and the cycle life of the material is the most important problem.In order to alleviate sintering,we try to dope the nickel ferrite with different quality zirconia and perform multiple thermochemical cycles to produce hydrogen.The experimental results show that doped zirconia has a certain effect on the suppression of sintering,and both the effective cycle life and hydrogen production of nickel ferrite has been improved to a certain extent.When the doping mass ratio is 1:1 or more,the doping effect of zirconia begins to be apparent.Comprehensively considering the factors such as the production of recycled hydrogen,heat loss and economic efficiency caused by zirconia doping,it is best to control the doping ratio at m?Ni Fe₂O₄?:m?Zr O₂?=2:3.?2?The second part is study on the hydrogen production catalyzed by nickel ferrite which is supported by porous alumina ceramics.Although the doping of zirconia has a certain effect on the suppression of ferrite sintering,the uneven distribution of the barrier and ferrite may occur during doping and affect the inhibitory effect of the barrier.In order to ensure the insulation effect,a large amount of barrier agent needs to be doped,which will cause a large amount of heat loss.In order to extend the cycle life of nickel ferrite more economically and effectively,an attempt was made to support nickel ferrite on porous alumina ceramics to suppress sintering.By comparing the hydrogen production capacity and number of cycles of nickel ferrite deposited on porous alumina and zirconia-doped nickel ferrite at different temperatures,it was found that the cycle life of porous alumina ceramics supporting nickel ferrite was significantly improved.The optimal reduction temperature of the nickel ferrite catalyst was investigated.Experiments found that when the reduction temperature is set at about 1250?,nickel ferrite supported by porous alumina ceramics could obtain the most hydrogen production in several thermochemical cycles.?3?The third part is study on the hydrogen production catalyzed by nickel manganese ferrite.Doping manganese in nickel ferrite can effectively reduce the temperature at which the catalyst decomposes and releases oxygen.In order to seek a high catalytic hydrogen production yield while ensuring a low reduction temperature,we have added its manganese metal element to nickel ferrite.The hydrogen-producing ability of nickel-manganese ferrite with different components was investigated,and it was found that Ni_0.5Mn_0.5Fe₂O₄ had the best hydrogen-producing ability at a reduction temperature of 1100?.In order to suppress sintering and prolong the effective cycle life of the catalyst,try to use porous alumina ceramics to support it and achieve good results.Compared with Ni Fe₂O₄ supported by porous alumina ceramics,Ni_0.5Mn_0.5Fe₂O₄ supported by porous alumina ceramics is a better catalyst which has lower requirements for reduction temperature,more hydrogen production output,and excellent cycle performance.