Xiangfeng Chu

Acetone Sensors Based on La3+ Doped ZnO Nano-rods Prepared by Solvothermal Method

La 3+ doped ZnO nano-rods with different doping concentration were prepared via solvothermal method. The doped ZnO nano-rods were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively The effect of La 3+ doping on the gas-sensing properties was investigated. The results revealed that the sensor based on 6 mol% La 3+ doped ZnO nano-rods exhibited high response to dilute acetone, and the responses to 0.01 × 10 −6 acetone reached 2.4 when operating at 425 °C. The response time and the recovery time for 0.01 × 10 −6 acetone were only 16 and 3 s, respectively.

NdFeO3 as anode material for S/O2 solid oxide fuel cells

Abstract Sulfur-oxygen solid oxide fuel cells (S/O2-SOFCs) can improve the utilization ratio of energy via converting the combustion heat of sulfur into electrical energy directly, and sulfur trioxide which is an intermediate in sulfuric acid industry can be obtained directly via S/O2-SOFCs. The anode material NdFeO3 was prepared via sol-gel method, the phase stability of NdFeO3 in sulfur vapor or sulfur dioxide atmosphere was investigated. The single cell, consisting of NdFeO3-SDC/SDC/LSM-SDC structure, was fabricated by the screen-printing method and tested by the home-built equipment with sulfur vapor or sulfur dioxide as the fuel. As indicated by X-ray diffraction (XRD) analysis, NdFeO3 was stable in sulfur vapor or sulfur dioxide atmosphere at 800 °C, the phase composition of the mixture of NdFeO3 and SDC (Sm doped CeO2) did not change after the mixture was calcined at 800 °C for 4 h. The transmission electron microscope (TEM) photograph revealed that the average grain size of NdFeO3 powder was about 80 nm. With sulfur vapor or SO2 as the fuel, the maximum open circuit voltages (OCVs) of the single cell were 409 mV at 620 °C and 474 mV at 650 °C, respectively; the maximum power densities of single cell were 0.154 mW/cm2 at 620 °C and 0.265 mW/cm2 at 650 °C, respectively.

Preparation and Gas-sensing Properties of Cu 2+ -doped ZnO Nanorods: Preparation and Gas-sensing Properties of Cu 2+ -doped ZnO Nanorods

通过溶剂热法(无水乙醇)制备了Cu 2+ (0~6mol%)掺杂ZnO纳米棒粉体, 采用X射线衍射仪和扫描电镜对掺杂ZnO纳米粉体的晶体结构和微观形貌进行了表征. 研究了Cu 2+ 掺杂比例、溶剂热反应温度及时间对材料气敏性能的影响; 考察ZnO(120℃, 10 h)和3mol% Cu 2+ 掺杂ZnO(120℃, 10 h)粉体对应元件对甲醛、乙酸、甲苯、乙醇、丙酮、三甲胺等六种气体的气敏性能. 结果表明: 通过溶剂热法制备的ZnO粉体为纳米棒状结构, 棒长度和直径随Cu 2+ 掺杂比例不同发生变化; 3mol% Cu 2+ 掺杂ZnO(120℃, 10 h)样品对应元件对低浓度乙醇有很好的选择性, 在395℃工作温度下对1×10 –3 乙醇的灵敏度为380.5, 响应恢复时间分别为5 s和40 s, 对1×10 –6 乙醇的灵敏度可达4.2.通过溶剂热法(无水乙醇)制备了Cu 2+ (0~6mol%)掺杂ZnO纳米棒粉体, 采用X射线衍射仪和扫描电镜对掺杂ZnO纳米粉体的晶体结构和微观形貌进行了表征. 研究了Cu 2+ 掺杂比例、溶剂热反应温度及时间对材料气敏性能的影响; 考察ZnO(120℃, 10 h)和3mol% Cu 2+ 掺杂ZnO(120℃, 10 h)粉体对应元件对甲醛、乙酸、甲苯、乙醇、丙酮、三甲胺等六种气体的气敏性能. 结果表明: 通过溶剂热法制备的ZnO粉体为纳米棒状结构, 棒长度和直径随Cu 2+ 掺杂比例不同发生变化; 3mol% Cu 2+ 掺杂ZnO(120℃, 10 h)样品对应元件对低浓度乙醇有很好的选择性, 在395℃工作温度下对1×10 –3 乙醇的灵敏度为380.5, 响应恢复时间分别为5 s和40 s, 对1×10 –6 乙醇的灵敏度可达4.2.

Cobalt-free Composite Ba0.5Sr0.5Fe0.9Ni0.1O3-δ-Ce0.8Sm0.2O2-δ as Cathode for Intermediate-Temperature Solid Oxide Fuel Cell

New cobalt-free composites consisting of Ba 0.5 Sr 0.5 Fe 0.9 Ni 0.1 O 3–δ (BSFN) and Ce 0.8 Sm 0.2 O 2–δ (SDC) were investigated as possible cathode materials for intermediate-temperature solid oxide fuel cell (IT-SOFC). BSFN, which was synthesized by auto ignition process, was chemically compatible with SDC up to 1100 °C as indicated by X-ray diffraction analysis. The electrical conductivity of BSFN reached the maximum value of 57 S·cm −1 at 450 °C. The thermal expansion coefficient (TEC) value of BSFN was 30.9×10 −6 K −1 , much higher than that of typical electrolytes. The electrochemical behavior of the composites was analyzed via electrochemical impedance spectroscopy with symmetrical cells BSFN-SDC/SDC/BSFN-SDC. The area specific interfacial polarization resistance (ASR) decreased with increasing SDC content of the composite. The area specific interfacial polarization resistance (ASR) at 700 °C is only 0.49, 0.34 and 0.31 Ω·cm 2 when 30, 40, and 50 wt% SDC was cooperated to BSFN, respectively. These results suggest that BSFN-SDC is a possible candidate for IT-SOFC cathode.