Tongtong Yao,Nianjun Hou,Juanjuan Gan,Jun Wang,Xiaojing Zhi,Lijun Fan,Tian Gan,Yicheng Zhao,Yongdan Li
Sr 2-x Na x FeMo 0.65 Ni 0.35 O 6-δ is synthesized as an anode material for solid oxide fuel cells. The effects of Na on the crystalline phase and electrical properties are investigated. The main perovskite phase changes into a Ruddlesden-Popper structure after reduction when x is less than 0.1, while the material with a higher amount of Na keeps the perovskite structure. FeNi x alloy nanoparticles are exsolved during reduction, in which the content of Ni increases with the rise of Na amount. The surface oxygen vacancy concentration is also influenced by the doping of Na, and the highest value is reached when x is 0.1. Sr 1.9 Na 0.1 FeMo 0.65 Ni 0.35 O 6-δ anode exhibits the highest activity, and a single cell supported by a 300-μm-thick La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3-δ electrolyte layer shows maximum power densities of 1495 and 627 mW cm −2 at 850 °C with H 2 and wet CH 4 as fuels, respectively. The coking resistance of the anode is also improved with Na doping.
The Ln 2 NiO 4+δ compound (Ln = La, Pr, Nd) finds extensive use as a cobalt-free oxygen electrode material in protonic ceramic electrolysis cells (PCECs) owing to its unique RP-type structure and remarkable catalytic activity . In this study, Cu and Zn co-substitution is employed to fabricate a series of materials, within the La 1 · 2 Sr 0 · 8 Ni 0.5 Cu x Zn 0.5-x O 4+δ system (x = 0.1, 0.2, 0.3, 0.4, denote as LSNCZ14, LSNCZ23, LSNCZ32, and LSNCZ41), and the crystal structure, conductivity, proton absorption and electrochemical properties are comprehensively investigated. The LSNCZ41 exhibits the lowest polarization resistance of 0.83 Ω cm 2 at 600 °C in the symmetric cell. The PCEC single cell incorporating the LSNCZ41 air electrode demonstrates a high electrolysis current density of 1.5 A cm −2 (1.3 V) at 600 °C under 60 % humidity in air, furthermore, negligible degradation is observed under this high current density during electrolysis for over 250 h. These results indicate that LSNCZ41 possesses a higher concentration of interstitial oxygen ions and superior proton absorption capacity , significantly expediting the oxygen reduction reaction (ORR) and ionic transport processes. This material can be considered as a promising candidate for the PCEC air electrodes due to its superior stability in air with high steam content.
Na Yang,Jingchao Yu,Longfei Zhang,Yongli Sun,Luhong Zhang,Bin Jiang
A 2 BO 4 -type perovskite with Ruddlesden-Popper structure performed favorable catalytic activity in the activation of peroxymonosulfate (PMS) for the degradation of organic pollutants than ABO 3 , but the higher forming temperature limits its further application. In this work, a series of A-site Sr doped La 2 CoO 4-δ perovskites were prepared and used for the degradation of tetracycline hydrochloride (TC). The introduction of Sr lowered the formation temperature of the perovskite and improved the catalytic capability. The LaSrCoO 4 perovskite with 50 % Sr doping possessed the best TC degradation efficiency (complete degradation in 14 min). Besides, to overcome the mass transfer limitation caused by catalyst powder agglomeration and the difficulty of recovery, perovskite powder catalysts were embedded in polyacrylonitrile (PAN) ultrafiltration membrane by phase conversion method. The resulting PAN/LSC catalytic separation membranes achieved efficient degradation of TC due to the partial increase in the concentration of contaminants inside the membrane pores. The membrane embedded with 5 wt% LaSrCoO 4 perovskite degraded 94 % TC in 3 min, which improved over 24 % compared to the perovskite powder. The catalytic degradation mechanism of TC and the toxicity of the intermediates were then analyzed. The effectiveness of catalytic membranes in practical applications was also evaluated. Overall, PAN/LSC membranes provide the potential for rapid purification of organic wastewater.
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