二甲醚的电催化氧化反应

 考察了负载于镓酸镧基电解质上的镍电极与镍－钐掺杂氧化铈复合电极电催化二甲醚氧化反应的特性．结果表明，反应的主要产物均为CO，H2和CH4，同时生成少量完全氧化的产物H2O和CO2．在开路电位下二甲醚发生裂解反应，生成的CO，H2和CH4三种主要产物的比例接近于1．在有电泵氧存在下，二甲醚的电催化氧化反应强烈地依赖于阳极及电解质材料的组成．Ni／La0．9Sr0．1Ga0．8Mg0．2O3界面上发生的主反应是二甲醚的部分氧化，且存在有严重的积碳现象．电极中掺入SDC（15％Sm3＋－掺杂的CeO2）后，二甲醚完全氧化性能明显增强；随着电流的增大，氢的生成速率显著减小，并生成大量的H2O．采用掺钴镓酸镧基电解质后，Ni－SDC主要表现为催化二甲醚部分氧化反应，且显著抑制了积碳的发生．Ni－SDC／La0．8Sr0．2Ga0．8－Mg0．11Co0．09O3上二甲醚电催化氧化反应的主要产物为1∶1的CO和H2．掺钴电解质引起Ni－SDC具有特殊的催化性能，可能与电解质中p型电导的存在有关．

Electrocatalytic Oxidation of Dimethyl Ether

As potential fuel for solid oxide fuel cells, electrocatalytic oxidation of dimethyl ether (DME) was studied on nickel and nickel samarium doped CeO 2 composite anodes supported on series lanthanum gallate electrolytes. The reaction was characterized in a single solid oxide fuel cell, and the electrolytes were La 0 8 Sr 0 2 Ga 0 8 Mg 0 11 Co 0 09 O 3 (LSGMC9), La 0 8 Sr 0 2 Ga 0 8 Mg 0 13 Co 0 07 O 3 (LSGMC7), La 0 8 Sr 0 2 Ga 0 8 Mg 0 15 Co 0 05 O 3 (LSGMC5), and La 0 9 Sr 0 1 Ga 0 8 Mg 0 2 O 3 (LSGM). The composition of composite anode was 75%Ni 25%SDC (SDC15%Sm 3+ doped CeO 2). The main products were CO, H 2 and CH 4 with small amounts of CO 2 and H 2O. DME was decomposed into CO, H 2, and CH 4 under open circuit voltage. The product distribution depended strongly on the composition of anode and electrolyte. The major reaction on Ni/LSGM was partial oxidation of DME, and significant coke deposition was observed during the reaction. With the addition of SDC into Ni anode, complete oxidation was preferred on the catalyst. The formation rate of H 2 decreased with the increase of current on Ni SDC/LSGM, and large amount of H 2O was formed in the reaction. While using Co doped LSGM electrolytes, the major reaction changed to partial oxidation of DME, and the coke deposition was significantly decreased. The main products on Ni SDC/LSGMC9 were CO and H 2. The special property of Co doped LSGM electrolyte could be due to the high p type conductivity. Ni SDC/LSGMC is a kind of ideal anode for electrocatalytic partial oxidation of DME.