Ni/YSZ fuel electrodes can only operate under strongly reducing conditions for steam elec- trolysis in an oxide-ion-conducting solid oxide electrolyzer （SOE）. In atmosphere with a low content of H2 or without H2, ca...Ni/YSZ fuel electrodes can only operate under strongly reducing conditions for steam elec- trolysis in an oxide-ion-conducting solid oxide electrolyzer （SOE）. In atmosphere with a low content of H2 or without H2, cathodes based on redox-reversible Nb2TiO7 provide a promising alternative. The reversible changes between oxidized Nb2TiO7 and reduced Nbl.33Tio.6704 samples are systematically investigated after redox-cycling tests. The conductivities of Nb2TiO7 and reduced Nb1.33Tio.6704 are studied as a function of temperature and oxygen partial pressure and correlated with the electrochemical properties of the composite electrodes in a symmetric cell and SOE at 830 ℃. Steam electrolysis is then performed using an oxide-ion-conducting SOE based on a Nb1.33Ti0.6704 composite fuel electrode at 830 ℃. The current-voltage and impedance spectroscopy tests demonstrate that the reduction and activation of the fuel electrode is the main process at low voltage; however, the steam electrolysis dominates the entire process at high voltages. The Faradic efficiencies of steam electrolysis reach 98.9% when 3%H2O/Ar/4%H2 is introduced to the fuel electrode and 89% for that with introduction of 3%H2O/Ar.展开更多
采用室温离子液体乙基三甲基咪唑双三氟甲磺酸亚胺盐(EMIMTFSI)替代原有钠/氯化金属电池(ZEBRA电池)的高熔点电解质氯铝酸钠(NaAlCl_4)来降低ZEBRA电池运行温度。利用循环伏安法、热分析法和交流阻抗法测试过渡金属Fe、Zn、Cu在离子液...采用室温离子液体乙基三甲基咪唑双三氟甲磺酸亚胺盐(EMIMTFSI)替代原有钠/氯化金属电池(ZEBRA电池)的高熔点电解质氯铝酸钠(NaAlCl_4)来降低ZEBRA电池运行温度。利用循环伏安法、热分析法和交流阻抗法测试过渡金属Fe、Zn、Cu在离子液体中氧化还原可逆性、热稳定性以及电导率。结果表明:Cu和Zn电极在该离子液体中的可逆性良好,可组装中温ZEBRA电池,组装的Na/CuCl_2电池可在175℃下平稳运行,首次放电比容量达273 m A·h/g,库伦效率接近100%。展开更多
Three compounds with nitrocarbazole frameworks were synthesized and their electrochemical reversibility as organic electrocatalysts was studied by cyclic voltammetry. The electrochemical reversibility and oxidation‐r...Three compounds with nitrocarbazole frameworks were synthesized and their electrochemical reversibility as organic electrocatalysts was studied by cyclic voltammetry. The electrochemical reversibility and oxidation‐reduction potential of the compounds were greatly affected by their substituents. The oxidation‐reduction potential of the compound with an electron‐donating group was negative, while that of the compound with an electron‐withdrawing group on the carbazole framework was positive. The electrocatalytic oxidation activities of the nitrocarbazole compounds were investigated through cyclic voltammetry and controlled potential electrolysis at room tem‐perature. The electrocatalysts showed excellent selectivity for p‐methoxybenzyl alcohol, converting it to the corresponding aldehyde through electro‐oxidation with just 2.5 mol%of the electrocata‐lysts presented. The electrocatalysts maintained their excellent electroredox activity following re‐cycling.展开更多
文摘Ni/YSZ fuel electrodes can only operate under strongly reducing conditions for steam elec- trolysis in an oxide-ion-conducting solid oxide electrolyzer （SOE）. In atmosphere with a low content of H2 or without H2, cathodes based on redox-reversible Nb2TiO7 provide a promising alternative. The reversible changes between oxidized Nb2TiO7 and reduced Nbl.33Tio.6704 samples are systematically investigated after redox-cycling tests. The conductivities of Nb2TiO7 and reduced Nb1.33Tio.6704 are studied as a function of temperature and oxygen partial pressure and correlated with the electrochemical properties of the composite electrodes in a symmetric cell and SOE at 830 ℃. Steam electrolysis is then performed using an oxide-ion-conducting SOE based on a Nb1.33Ti0.6704 composite fuel electrode at 830 ℃. The current-voltage and impedance spectroscopy tests demonstrate that the reduction and activation of the fuel electrode is the main process at low voltage; however, the steam electrolysis dominates the entire process at high voltages. The Faradic efficiencies of steam electrolysis reach 98.9% when 3%H2O/Ar/4%H2 is introduced to the fuel electrode and 89% for that with introduction of 3%H2O/Ar.
文摘采用室温离子液体乙基三甲基咪唑双三氟甲磺酸亚胺盐(EMIMTFSI)替代原有钠/氯化金属电池(ZEBRA电池)的高熔点电解质氯铝酸钠(NaAlCl_4)来降低ZEBRA电池运行温度。利用循环伏安法、热分析法和交流阻抗法测试过渡金属Fe、Zn、Cu在离子液体中氧化还原可逆性、热稳定性以及电导率。结果表明:Cu和Zn电极在该离子液体中的可逆性良好,可组装中温ZEBRA电池,组装的Na/CuCl_2电池可在175℃下平稳运行,首次放电比容量达273 m A·h/g,库伦效率接近100%。
基金supported by the Special Program for the National Basic Research Program of China(973 Program,2012CB722604)~~
文摘Three compounds with nitrocarbazole frameworks were synthesized and their electrochemical reversibility as organic electrocatalysts was studied by cyclic voltammetry. The electrochemical reversibility and oxidation‐reduction potential of the compounds were greatly affected by their substituents. The oxidation‐reduction potential of the compound with an electron‐donating group was negative, while that of the compound with an electron‐withdrawing group on the carbazole framework was positive. The electrocatalytic oxidation activities of the nitrocarbazole compounds were investigated through cyclic voltammetry and controlled potential electrolysis at room tem‐perature. The electrocatalysts showed excellent selectivity for p‐methoxybenzyl alcohol, converting it to the corresponding aldehyde through electro‐oxidation with just 2.5 mol%of the electrocata‐lysts presented. The electrocatalysts maintained their excellent electroredox activity following re‐cycling.
