| TiNx membrane have attracted extensive attention in the field of hydrogen purification because of their properties of catalyzing the dissociation of hydrogen molecules into hydrogen atoms.In this paper,the effects of process parameters such as nitrogen partial pressure,power supply,bias voltage and substrate temperature on the phase and structure of TiNx hydrogen catalytic membrane were studied systematically by magnetron sputtering membrane preparation technology.Based on the hydrogen evolution catalytic properties of the prepared TiNx membrane,the TiN0.70/V85Ni15/TiN0.70 hydrogen separation composite membrane is prepared by using the TiNx membrane with the highest catalytic activity and the V85Ni15 as-cast alloy membrane with good hydrogen embrittlement resistance as the substrate.The hydrogen transport properties such as hydrogen permeation and hydrogen dissolution were systematically studied,and compared with the performance of the traditional Pd/V85Ni15/Pd hydrogen separation composite membrane.The results of XRD grazing,EDS surface scanning and electrochemical test analysis of TiNx membrane show that the process parameters are 10%nitrogen partial pressure,power supply power 200W,substrate negative bias voltage 200V and substrate temperature 400°C.The single-phase NaCl-type TiN0.70 membrane?111?has the strongest diffraction peak and the best electrocatalytic hydrogen evolution performance.The electrochemical LSV and EIS test results are significantly superior to other process parameters.The SEM test results of the TiN0.70 membrane show that it is a nanocrystalline structure,which is a nano-scale columnar crystal grown perpendicular to the substrate,and the surface is quite flat.The sputtering rate of magnetron sputtering is calculated by the film thickness to be about 13.85 nm/min.The results of hydrogen dissolution experiments show that the process of dissolving hydrogen in TiN0.70/V85Ni15/TiN0.70 hydrogen separation composite membrane is an exothermic process,and its conformity with Sieverts law is better at473K.The theoretical of hydrogen diffusion driving force is provided by chemical potential gradient shows that the permeation amount has a good proportional linear relationship with the PCT factor,and as the temperature increases,the linear slope increases,so the migration rate of hydrogen atoms in the hydrogen separation composite membrane is also increases.The results of hydrogen permeation experiments show that the TiN0.70/V85Ni15/TiN0.70 hydrogen separation composite membrane has good hydrogen permeation performance,and its hydrogen permeability coefficients at 323K,373K473K and 673K are 4.22×10-9,6.22×10-9,1.16×10-8 and 2.18×10-8molH2 m-11 s-11 Pa-0.5.The hydrogen transport properties of TiN0.70/V85Ni15/TiN0.70 hydrogen separation composite membrane was further analyzed.The value of hydrogen intrinsic diffusion coefficient at 473K was calculated to be 6.8×10-10 m2/s,which was much higher than Pd/V85Ni15/Pd hydrogen separation composite membrane.The hydrogen intrinsic diffusion coefficient of the Pd/V85Ni15/Pd hydrogen separation composite membrane at523K was calculated to be 3.6×10-10 m2/s.At the same time,the hydrogen intrinsic diffusion coefficient of TiN0.70/V85Ni15/TiN0.70 hydrogen separation composite membrane at 673K was calculated to be 18.2×10-10 m2/s and the hydrogen intrinsic diffusion coefficient of Pd/V85Ni15/Pd hydrogen separation composite membrane at673K was calculated to be 18.0×10-10 m2/s.Furthermore,it is analyzed that its hydrogen diffusion performance is stronger than Pd/V85Ni15/Pd hydrogen separation composite membrane in the temperature range below 673K. |
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