Bausá Nuria, Serra José M
Instituto de Tecnología Química (Universitat Politècnica de València - Consejo Superior de Investigaciones Científicas) Av. Naranjos s/n E-46022 Valencia Spain
RSC Adv. 2019 Jul 2;9(36):20677-20686. doi: 10.1039/c9ra04044g. eCollection 2019 Jul 1.
Backbone electrodes based on an electronic conductor and a protonic conductor show advantages for proton ceramic electrolyzer cells (PCECs). This work, aims to shed further light on the nature of the rate determining steps in the anode operation and improve the reaction rate in high steam pressure electrolysis mode by (i) adjusting their catalytic activity through electrode infiltration with catalytic electronic-conducting nanoparticles; and (ii) electrochemical activation of surface species by applying a net current through the electrode. A composite formed by LaSrMnO (LSM) and BaCeZrYO (BCZY27) was deposited on proton-conducting BCZY27 electrolytes and studied in symmetrical cells to investigate the anode microstructure and electrochemical performance. Electrochemical impedance spectroscopy (EIS) measurements were performed in the 800-500 °C range under 3 bar of pressure of wet air (75% of steam). LSM/BCZY27 50/50 vol% showed the best performance with an electrode polarization resistance ( ) of 6.04 Ω cm at 700 °C and high steam pressure (0.75 bar of air and 2.25 bar of steam) whereas LSM/BCZY27 60/40 vol% presented a of 18.9 Ω cm. The backbone electrodes were infiltrated using aqueous solutions of metal precursors to boost the electrocatalytic activity towards water splitting and oxygen evolution. The infiltrated cells were fired at 850 °C for 2 h to obtain the desired crystalline nanoparticles (PrO, CeO, ZrO and PrO-CeO) and electrochemically tested under high steam pressures and bias currents to investigate the influence of catalytic activation on surface exchange kinetics. Among the tested catalysts, the lowest electrode polarization resistances (<0.2 Ω cm) were reached for the PrO, CeO and PrO-CeO catalysts at 700 °C by applying current densities ranging from 1.57 to 14.15 mA cm, and the PrO-CeO-activated LSM/BCZY27 electrode exhibited the best performance. Finally, the effect of O and HO was investigated aiming to characterize the rate limiting processes in the electrodes.
基于电子导体和质子导体的骨架电极在质子陶瓷电解槽电池（PCEC）中显示出优势。这项工作旨在进一步阐明阳极运行中速率决定步骤的本质，并通过以下方式提高高蒸汽压电解模式下的反应速率：（i）通过用催化电子导电纳米颗粒渗透电极来调节其催化活性；（ii）通过在电极上施加净电流对表面物种进行电化学活化。由LaSrMnO（LSM）和BaCeZrYO（BCZY27）形成的复合材料沉积在质子导电的BCZY27电解质上，并在对称电池中进行研究，以考察阳极微观结构和电化学性能。在800 - 500℃范围内、3巴湿空气（75%蒸汽）压力下进行电化学阻抗谱（EIS）测量。LSM/BCZY27 50/50体积%在700℃和高蒸汽压（0.75巴空气和2.25巴蒸汽）下表现出最佳性能，电极极化电阻（ ）为6.04Ω·cm，而LSM/BCZY27 60/40体积%的极化电阻为18.9Ω·cm。使用金属前驱体的水溶液渗透骨架电极，以提高对水分解和析氧的电催化活性。渗透后的电池在850℃下烧制2小时，以获得所需的结晶纳米颗粒（PrO、CeO、ZrO和PrO - CeO），并在高蒸汽压和偏置电流下进行电化学测试，以研究催化活化对表面交换动力学的影响。在测试的催化剂中，通过施加1.57至14.15 mA/cm的电流密度，PrO、CeO和PrO - CeO催化剂在700℃时达到了最低的电极极化电阻（<0.2Ω·cm），并且PrO - CeO活化的LSM/BCZY27电极表现出最佳性能。最后，研究了O和HO的影响，旨在表征电极中的速率限制过程。
