DIRECT ELECTROCHEMICAL POWER GENERATION FROM CARBON IN FUEL CELLS WITH MOLTEN HYDROXIDE ELECTROLYTE

Historically, despite its compelling cost and performance advantages, the use of a molten metal hydroxide electrolyte has been ignored by direct carbon fuel cell (DCFC) researchers, primarily due to the potential for formation of carbonate salt in the cell. This article describes the electrochemistry of a patented medium-temperature DCFC based on a molten hydroxide electrolyte, which overcomes the historical carbonate formation.

An important technique discovered for significantly reducing carbonate formation in the DCFC is to ensure a high water content of the electrolyte. To date, four successive generations of DCFC prototypes have been built and tested to demonstrate the technology - all using graphite rods as their fuel source. These cells all used a simple design in which the cell containers served as the air cathodes and successfully demonstrated the ability to deliver more than 40 A with the current density exceeding 250 mA/cm². Conversion efficiency greater than 60% was achieved.     

CHARACTERIZATION OF CERIUM OXIDE AND CARBON SUPPORTED Ag-Cu ELECTRO-CATALYSTS FOR ANODE ELECTRODE IN DIRECT ETHANOL FUEL CELLS

In this study, electrochemical and spectroscopic characterization of home-made CeO₂, activated carbon-based Ag-Cu electro-catalysts, and preliminary anode polarization results in a direct ethanol fuel cell test system were presented. Ag-Cu transition metal couples were impregnated onto carbon and cerium oxide supports by wet impregnation, ion exchange, and co-precipitation techniques. Wet impregnation technique was selected for further spectroscopic analysis and fuel cell testing due to its easy metal loading advantage and highest peak currents in ethanol-containing electrolyte environment. When Ag and Cu were loaded 37.5 and 12.5 wt.% onto carbon and cerium oxide by wet impregnation technique, XPS analysis indicated an appreciable amount of Ag and Ag₂O and a high amount of CuO. In cerium oxide-based samples atomic percentage of oxygen fits well with the stoichiometry of CuO/CeO₂. Preliminary results show that BET surface area and the current peaks exhibit a close resemblance (highest BET surface area indicates highest anodic dissolution current), which is thought to be due to the high accessibility of copper layers impregnated onto cerium oxide and activated carbon in H₂SO₄ electrolyte environment. Hydrogen reduction of CeO₂-based samples prepared by wet impregnation at 750°C greatly improved anode polarization and onset oxidation potential.     

固体氧化物电解质燃料电池阴极研究的新进展

阴极（空气电极）是固体氧化物电解质燃料电池的关键部件之一.本文总结了近年来关于固体氧化物电解质燃料电池阴极的研究状况，包括材料的选择和制备、电极的制备和电化学性质的研究，提出了今后的研究重点．     

阳极负载型H2S中温固体氧化物燃料电池电输出性能

以NiO-(CeO2)1-2x(Sm2O3)x固体氧化物燃料电池(solid oxide fuel cell,SOFC)的阳极负载,采用甘氨酸-硝酸盐燃烧法制备(CeO2)0.8(Sm2O3)0.1固体电解质前驱体粉末并流延成膜.在中温(650～850℃),分别测定了H2S-Air SOFC的电输出性能随H2S流速r(H2S)、运行温度的变化情况.实验结果表明:SOFC的开路电压随r(H2S)的增大而呈指数关系增大.电流密度-电压(电功率密度)曲线显示:SOFC电输出性能随r(H2S)的增大而改善;但当r(H2S)=80mL/min时,在高电流密度区间输出电压出现明显的下降,这是由于流速增大产生的浓差极化和阳极Ni受H2S腐蚀导致的结果.温度对极化曲线影响表明,SOFC电输出性能随温度的升高而改善,但基于(CeO2)0.8(Sm2O3)0.1离子-电子混合导电等原因,单体电池开路电压受温度影响比较复杂.     

Ni-CGO阳极支撑ScSZ/CGO复合电解质电池的制备及性能

用柠檬酸溶胶-凝胶法合成了Ce0.85Gd0.15O2-δ(CGO),用共沉淀法合成了掺摩尔分数为11%Sc2O3稳定的ZrO2(scandium oxide-stabilized zirconia,ScSZ)电解质材料.通过X射线衍射和透射电镜对电解质材料的物相、形貌和成分进行表征.结果表明:CGO和ScSZ在各自的煅烧温度下均形成了单-的立方萤石结构晶态;ScSZ颗粒的粒径约为20nm.用共压法分别制备了以NiO-CGO阳极支撑的CGO单层电解质和ScSZ/CGO复合电解质的基体,并在基体上涂覆阴极制作单电池.在650～800℃范围内测试单电池的电性能.结果表明:ScSZ/CGO双层电解质电池的开路电压和最大功率密度均高于单层CGO电解质电池;在800℃电流密度和功率密度达到最大值,分别为677.5 mA/cm2和197.3 mW/cm2.说明SeSZ/CGO双层电解质有效地提高了电池的性能.     

IN-SITU FT-IR SPECTROSCOPIC STUDIES OF FUEL CELL ELECTRO-CATALYSIS: FROM SINGLE-CRYSTAL TO NANOPARTICLE SURFACES

The work presented in this article shows the power of the variable temperature, in-situ FT-IR spectroscopy system developed in Newcastle with respect to the investigation of fuel cell electro-catalysis. On the Ru(0001) electrode surface, CO co-adsorbs with the oxygen-containing adlayers to form mixed [CO + (2 × 2)–O(H)] domains. The electro-oxidation of the Ru(0001) surface leads to the formation of active (1 × 1)–O(H) domains, and the oxidation of adsorbed CO then takes place at the perimeter of these domains. At 20°C, the adsorbed CO is present as rather compact islands. In contrast, at 60°C, the CO_ads is present as a relatively looser and weaker adlayer. Higher temperature was also found to facilitate the surface diffusion and oxidation of CO_ads. No dissociation or electro-oxidation of methanol was observed at potentials below approximately 950 mV; however, the Ru(0001) surface at high anodic potentials was observed to be very active. On both Pt and PtRu nanoparticle surfaces, only one linear bond CO adsorbate was formed from methanol adsorption, and the PtRu surface significantly promoted both methanol dissociative adsorption to CO and its further oxidation to CO₂. Increasing temperature from 20° to 60°C significantly facilitates the methanol turnover to CO₂.     

IN-SITU FT-IR SPECTROSCOPIC STUDIES OF FUEL CELL ELECTRO-CATALYSIS: FROM SINGLE-CRYSTAL TO NANOPARTICLE SURFACES

The work presented in this article shows the power of the variable temperature, in-situ FT-IR spectroscopy system developed in Newcastle with respect to the investigation of fuel cell electro-catalysis. On the Ru(0001) electrode surface, CO co-adsorbs with the oxygen-containing adlayers to form mixed [CO + (2 × 2)-O(H)] domains. The electro-oxidation of the Ru(0001) surface leads to the formation of active (1 × 1)-O(H) domains, and the oxidation of adsorbed CO then takes place at the perimeter of these domains. At 20°C, the adsorbed CO is present as rather compact islands. In contrast, at 60°C, the CO_ads is present as a relatively looser and weaker adlayer. Higher temperature was also found to facilitate the surface diffusion and oxidation of CO_ads. No dissociation or electro-oxidation of methanol was observed at potentials below approximately 950 mV; however, the Ru(0001) surface at high anodic potentials was observed to be very active. On both Pt and PtRu nanoparticle surfaces, only one linear bond CO adsorbate was formed from methanol adsorption, and the PtRu surface significantly promoted both methanol dissociative adsorption to CO and its further oxidation to CO₂. Increasing temperature from 20° to 60°C significantly facilitates the methanol turnover to CO₂.     

同步污水处理/发电技术-微生物燃料电池的研究进展

同步污水处理／发电技术的微生物燃料电池是利用生物催化剂直接把化学能转化为电能,具有能量转化率高、污泥产率低、反应条件温和等优点。本文阐述了微生物燃料电池的工作原理,反应器的类型及结构,综述了其最新的研究进展,并对微生物燃料电池在污水处理领域的发展方向作了展望。     

中国铝用炭阳极市场供需状况的回顾与展望

分析了中国炼铝技术的进展与阳极炭块(铝用炭阳极)市场的发展与演变，计算了铝厂建设和铝生产对炭阳极的需求；根据中国阳极炭块的产量情况，指出市场竞争刺激优质阳极生产；预测未来中国铝生产和阳极炭块市场发展；对阳极生产发展中的一些问题提出思考意见。