Zakharchuk Kiryl, Kovalevsky Andrei, Yaremchenko Aleksey
Department of Materials and Ceramic Engineering, CICECO-Aveiro Institute of Materials, University of Aveiro, 3810-193 Aveiro, Portugal.
Materials (Basel). 2023 Feb 20;16(4):1755. doi: 10.3390/ma16041755.
Ruddlesden-Popper LaBaNiO ( = 0-1.1) nickelates were prepared by a glycine-nitrate combustion route combined with high-temperature processing and evaluated for potential application as electrocatalysts for solid oxide cells and electrochemical NO elimination. The characterization included structural, microstructural and dilatometric studies, determination of oxygen nonstoichiometry, measurements of electrical conductivity and oxygen permeability, and assessment of chemical compatibility with other materials. The formation range of phase-pure solid solutions was found to be limited to = 0.5. Exceeding this limit leads to the co-existence of the main nickelate phase with low-melting Ba- and Ni-based secondary phases responsible for a strong reactivity with Pt components in experimental cells. Acceptor-type substitution of lanthanum by barium in LaBaNiO is charge-compensated by decreasing oxygen excess, from δ ≈ 0.1 for = 0 to nearly oxygen-stoichiometric state for = 0.5 at 800 °C in air, and generation of electron-holes (formation of Ni). This leads to an increase in -type electronic conductivity (up to ~80 S/cm for highly porous LaBaNiO ceramics at 450-900 °C) and a decline of oxygen-ionic transport. LaBaNiO ( = 0-0.5) ceramics exhibit moderate thermal expansion coefficients, 13.8-14.3 ppm/K at 25-1000 °C in air. These ceramic materials react with yttria-stabilized zirconia at 700 °C with the formation of an insulating LaZrO phase but show good chemical compatibility with BaZrYO solid electrolyte.
通过甘氨酸 - 硝酸盐燃烧法结合高温处理制备了Ruddlesden - Popper型LaBaNiO₃₊δ（δ = 0 - 1.1）镍酸盐，并对其作为固体氧化物电池的电催化剂和电化学NO消除的潜在应用进行了评估。表征包括结构、微观结构和膨胀学研究、氧非化学计量的测定、电导率和氧渗透率的测量，以及与其他材料的化学相容性评估。发现纯相固溶体的形成范围限于δ = 0.5。超过此极限会导致主要镍酸盐相与低熔点的Ba基和Ni基第二相共存，这些第二相在实验电池中与Pt组分发生强烈反应。在LaBaNiO₃₊δ中用钡对镧进行受主型取代，通过减少氧过量来进行电荷补偿，在空气中800℃时，从δ≈0.1（对于δ = 0）到δ = 0.5时接近氧化学计量状态，并产生电子空穴（形成Ni⁴⁺）。这导致n型电子电导率增加（对于高度多孔的LaBaNiO₃₊δ陶瓷，在450 - 900℃时高达约80 S/cm），氧离子传输下降。LaBaNiO₃₊δ（δ = 0 - 0.5）陶瓷在空气中25 - 1000℃时表现出中等的热膨胀系数，为13.8 - 14.3 ppm/K。这些陶瓷材料在700℃时与氧化钇稳定的氧化锆反应形成绝缘的LaZrO₃相，但与BaZrY₀.₁O₃ - δ固体电解质表现出良好的化学相容性。
