| With the decrease of fossil fuels such as coal,oil and natural gas and the environmental pollution caused by the use of fossil fuels,hydrogen energy has become the focus of people's research due to its advantages of energy saving,high efficiency,environmental protection and renewable energy.In industry,alkaline hydrolysis is mostly used to produce hydrogen on a large scale.Because hydrogen evolution overpotential is high,resulting in high energy consumption and cost,it is necessary to develop electrode materials with low hydrogen evolution overpotential.The laboratory has designed and established a large electrode production workshop to produce foam nickel/Ni-Mo alloy by ammonia-sodium molybdate process,which has a low hydrogen evolution overpotential.Due to the large amount of ammonia water used in the ammonia-sodium molybdate process,the volatile ammonia water needs to maintain the pH value of the plating solution to maintain the stability of the production process,and the volatile ammonia gas pollutes the air in the production site.The adhesion of foam nickel/Ni-Mo alloy layer prepared by material C process is poor.This paper mainly focuses on the improvement of these two processes for the preparation of foamed nickel/Ni-Mo alloys.The preparation of foamed nickel/Ni-Mo alloy by ammonia water-substance A process was studied.By orthogonal experiment and single-factor experiment got the best technology of nickel foam/Ni-Mo alloy recipe for NiSO4·6H2O 60g/L,Na3Cit·2H2O 120g/L,material A 6g/L,NaCl 10g/L,additiveB 0.6g/L,NH3·H2O20mL/L,pH9.12,temperature 25?,the current density of 85mA/cm2,time for 30min,medium speed.Measured the nickel foam/Ni-Mo alloy electrode at 25?,30wt%KOH solution of cathodic polarization curves,tafel constants a is 336mV,exchange current density of 30.9mA/cm2,at 200mA/cm2 current density of hydrogen evolution overpotential of 207mV.Using cathodic electrolysis nickel foam was investigated/Ni-Mo alloy at 90?,30wt%KOH solution in the binding force,the plating quality loss,less binding force is good.The apparent morphology of nickel foam/Ni-Mo alloy was observed by scanning electron microscopy.The surface of the coating was enlarged 300 times without cracking or peeling,and the surface of the coating was enlarged 5000 times without obvious cracks.The results of energy spectrometer showed that the atomic composition of nickel foam/Ni-Mo alloy coating was Ni87.1Mo12.9.An optimized material C process for the preparation of foamed nickel/Ni-Mo alloys was studied.In order to improve the adhesion of alloy coating,the activity of hydrogen evolution and the adhesion of alloy were taken into account.By reducing the current density and concentration of sodium molybdate nickel foam/Ni-Mo alloy the best technology of recipe for NiSO4·6H2O 105g/L,Na3Cit·2H2O 110g/L,Na2MoO4·2H2O 25g/L,NaCl 10g/L,additive B 0.4g/L,material C 31mL/L,pH9,temperature of 35?,the current density of 105 mA/cm2,time for 30 min,medium speed.Measured the nickel foam/Ni-Mo alloy electrode at 25?,30wt%KOH solution of cathodic polarization curve,get a 430.4mV tafel constants,exchange current density of 33.2mA/cm2,at 200mA/cm2 current density of hydrogen evolution overpotential of201 mV.Using cathodic electrolysis nickel foam was investigated/Ni-Mo alloy at 90?,30wt%KOH solution in the binding force,alloy electrode binding force has a certain increase before the process optimization.The apparent morphology of nickel foam/Ni-Mo alloy was observed by scanning electron microscopy.The coating surface was 500 times enlarged without peeling and cracking.The coating surface was 3,000times enlarged with ellipsoidal particles at the micron level.The atomic composition of the nickel foam/Ni-Mo alloy coating was Ni89.0Mo11.0.The pilot test of ammonia water-substance A process and material C process process was carried out.Using these two kinds of process were prepared respectively12cm×12cm foam nickel/Ni-Mo alloy,using filter type cell study its comprehensive performance,will be 90?,30wt%KOH solution as the electrolyte,current density of400mA/cm2,the pressure of 0.6MPa.Eight samples were successively prepared by ammonia water-substance A process.The first and second samples showed low surface density,which did not meet the requirements.The third and eighth samples showed uniform black appearance and surface density of 400450g/m2 for assessment.Twelve samples were successively prepared by material C optimization process.The first three samples had low surface density,the fourth and fifth samples had uneven color,and the12th sample had high surface density,all of which did not meet the requirements.The sixth and eleventh samples with uniform black appearance and surface density of460490g/m2 were selected for assessment.The results show that the average chamber pressure of nickel foam/Ni-Mo alloy prepared by ammonia water-substance A process is about 2mV higher than that of ammonia-sodium molybdate process.The average cell pressure of nickel foam/Ni-Mo alloy prepared by the optimized process of material C was about 40mV lower than that of ammonia water-substance A process,but the adhesion of the coating was poor.The coating solution of ammonia water-substance A process was stable,the resultant force of nickel foam/Ni-Mo alloy was better,and the amount of ammonia water was greatly reduced,which improved the air quality of the production site. |
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