EDTA-柠檬酸络合法制备阳极催化剂La0.7Sr0.3Cr0.87Y0.13O3-δ及热力学分析

摘要

采用EDTA−柠檬酸络合法制备固体氧化物燃料电池钙钛矿型耐硫阳极催化剂La0.7Sr0.3Cr0.87Y0.13O3−δ。采用TG−DSC对EDTA−柠檬酸络合法制备的阳极溶胶的热分解温度及晶相的形成温度进行分析；采用XRD和SEM等分析手段对烧结后的阳极粉末进行表征，并与尿素燃烧法制备的阳极粉末进行对比。再通过热力学软件计算分析阳极在H2S气氛中于一定氧分压(p(O2))和硫分压(p(S2))下的稳定性，对硫化前后阳极粉末的红外光谱进行对比分析，并对其耐硫性进行验证。结果表明：EDTA−柠檬酸络合法可以降低La0.7Sr0.3Cr0.87Y0.13O3−δ的烧结温度；La0.7­ Sr0.3Cr0.87Y0.13O3−δ具有一定的耐硫性能，升高操作温度和增大氧分压可以提高其耐硫性，符合耐硫阳极的要求。%The perovskite­type sulfur tolerant anode catalyst La0.7Sr0.3Cr0.87Y0.13O3−δ (LSCY) for solid oxide fuel cells (SOFCs) was synthesized by EDTA­citrate complexing method. The thermal decomposition temperature and forming temperature of the crystal phase of the gel prepared by EDTA­citrate complexing method were analyzed by TG−DSC. The powders after sintering were characterized by XRD and SEM, and compared with the powders prepared by urea combustion method. The thermodynamic calculation was made to analyze the stability of the anode materials when being exposed to H2S in a range of partial pressures of sulphur (p(S2)) and oxygen (p(O2)). The infrared spectra of the anode were compared before and after exposure to H2S to test the resistance to sulfur. The results show that the sintering temperature is decreased by using EDTA­citrate complexing method, the La0.7Sr0.3Cr0.87Y0.13O3−δis resistant to sulfur, and increasing the operating temperature and the partial pressures of oxygen (pO2) can improve its resistance to sulfur. Therefore, it meets the requirements of sulfur­ tolerant anode.