Enhancement of hydrogenation kinetics and thermodynamic properties of ZrCo_1-xCr_x（x = 0–0.1） alloys for hydrogen storage

【摘要】 The vacuum arc melting method was used to prepare ZrCo_1-xCr_x （x=0,0.025,0.05,0.075,0.1） alloys.Afterward,the crystal structure,hydrogenation kinetics,thermodynamic properties,and disproportionation performance of ZrCo_1-xCr_x （x=0–0.1） alloys were investigated.The x-ray diffraction spectra demonstrated that ZrCo_1-xCr_x （x=0–0.1） alloys contained ZrCo and ZrCo₂ phases,and their corresponding hydrides consisted of ZrCo H3and Zr H phases.The activation behaviors of Cr-substituted samples were significantly promoted.The activation time of ZrCo was 7715 s while that of ZrCo_0.9Cr_0.1 was 195 s.The improvement of kinetics can be attributed to the catalytic hydrogenation of ZrCr₂.The activation energy for the hydrogenation of ZrCo was 44.88-k J·mol^-1H2and decreased to 40.34-k J·mol^-1H₂ for ZrCo_0.95Cr_0.05.The plateau pressure and width of the pressure–composition–temperature curves decreased slightly as Cr content increased.The extent of disproportionation of ZrCo was 83.68%after being insulated at 798 K for 10 h and decreased slightly to 70.52%for ZrCo_0.9Cr_0.1.The improvement of anti-disproportionation performance can be attributed to increase in the activation energy of disproportionation from 167.46-k J·mol^-1H₂ for ZrCo to 168.28-k J·mol^-1H₂ for ZrCo_0.95Cr_0.05.更多还原

【Abstract】 The vacuum arc melting method was used to prepare ZrCo_1-xCr_x （x=0,0.025,0.05,0.075,0.1） alloys.Afterward,the crystal structure,hydrogenation kinetics,thermodynamic properties,and disproportionation performance of ZrCo_1-xCr_x （x=0–0.1） alloys were investigated.The x-ray diffraction spectra demonstrated that ZrCo_1-xCr_x （x=0–0.1） alloys contained ZrCo and ZrCo₂ phases,and their corresponding hydrides consisted of ZrCo H3and Zr H phases.The activation behaviors of Cr-substituted samples were significantly promoted.The activation time of ZrCo was 7715 s while that of ZrCo_0.9Cr_0.1 was 195 s.The improvement of kinetics can be attributed to the catalytic hydrogenation of ZrCr₂.The activation energy for the hydrogenation of ZrCo was 44.88-k J·mol^-1H2and decreased to 40.34-k J·mol^-1H₂ for ZrCo_0.95Cr_0.05.The plateau pressure and width of the pressure–composition–temperature curves decreased slightly as Cr content increased.The extent of disproportionation of ZrCo was 83.68%after being insulated at 798 K for 10 h and decreased slightly to 70.52%for ZrCo_0.9Cr_0.1.The improvement of anti-disproportionation performance can be attributed to increase in the activation energy of disproportionation from 167.46-k J·mol^-1H₂ for ZrCo to 168.28-k J·mol^-1H₂ for ZrCo_0.95Cr_0.05.更多还原