Application Of Two-dimensional MXene Hydrogen Permeable Membrane Reactor For Hydrogen Production By Ammonia Decomposition

Energy and environmental issues have become one of the issues of universal concern around the world.Traditional energy can neither meet people’s long-term needs,but also emit a large amount of carbon oxides and cause environmental pollution.Therefore,the development and application of new energy is of great significance.In the development of many new energy sources,hydrogen energy is favored for its advantages of non-pollution,reusable,and high combustion value.In recent years,the production of hydrogen by ammonia decomposition has received widespread attention.This method has the advantages of high purity,small footprint,simple operation,low cost,and no harmful by-products.Hydrogen production by ammonia decomposition offers a solution to the energy problem.In this study,we developed a membrane reactor supported MXene（Ti₃C₂T_X）for hydrogen production by ammonia decomposition.MXene membrane was deposited on the AAO substrate using vacuum-assisted filtration.The mebrane reactor supported MXene demonstrated a H₂ permeability of 2.06×10^-7 mol·m^-2·s^-1·Pa^-1 and H₂/N₂selectivity of 29 at 60 ^oC.The Ni-La/γ-Al₂O₃ catalyst was prepared by impregnation and sintering.Furthermore,the membrane reactor supported MXene（Ti₃C₂T_X）achieved an NH₃ conversion of 99%at 500 ^oC,9%higher than that of the packed catalytic reactor（without membrane）.In addition,a mathematical model of the membrane reactor was developed to help interpret and support the experimental results.The calculated activation energies(E_ad)of the MXene membrane for H₂ and N₂ permeance were 64.95and 69.53 k J·mol^-1,respectively.The activation energy(E_ar)of ammonia decomposition was 147.8 k J·mol^-1.In conclusion,the experimental and modeling results show that the membrane reactor could enhance NH₃ conversion and promote the production of high-purity hydrogen.Using the layered structure of MXene membrane,a vertical array gas separation membrane was constructed using a physical cutting and reassembly strategy.Compared to parallel zigzag channel membranes,gas molecules can directly enter the interlayer channels of vertical array membranes,significantly shortening the transmission distance and reducing the diffusion resistance.Molecules can quickly enter the interlayer to achieve molecular sieving.The vertical array MXene/r GO composite membrane formed by vacuum drying and self-precipitation of MXene/r GO colloidal solution at room temperature has a separation ratio of about 24 for the H₂/N₂ mixture,and a hydrogen permeation rate of 3.85×10^-7mol·m^-2·s^-1·Pa^-1.The hydrogen permeation rate has been significantly improved compared to the horizontal array membrane.