Redox dynamics of sulphur with Ni/GDC anode during SOFC operation at mid- and low-range temperatures: An operando S K-edge XANES study
Redox dynamics of sulphur with Ni/GDC anode during SOFC operation at mid- and low-range temperatures: An operando S K-edge XANES study
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SOFC 在中低温运行期间使用 Ni/GDC 阳极进行硫的氧化还原动力学：一项操作 S K-edge XANES 研究
DOI：
10.1016/j.jpowsour.2013.03.187
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发表时间：
2013
影响因子：
9.2
通讯作者：
R. Struis
中科院分区：
文献类型：
--
作者：
G. Nurk;T. Huthwelker;A. Braun;C. Ludwig;E. Lust;R. Struis
镍基固体氧化物燃料电池(SOFC)阳极催化剂的硫中毒是一个众所周知的缺陷，但尚未完全了解。本文提出了一种新的实验方法来获得实际操作条件下的光谱信息，特别是实际操作条件下固体氧化物燃料电池阳极的K壳层X射线吸收近边结构(XANES)区中硫物种的分子结构，从而使O2−流量从阴极流向阳极。从T=550C逐步冷却到250C，5ppm的H_2S/H_2与掺镍氧化铈(GdC)的阳极反应，产生几种不同氧化态(6+，4+，0，−2)的硫物种，在高温下硫化物的数量最少。根据硫形态分析，硫化物可能分别与-−或SO_3(G)、-SO_3·−或SO_2(G)、S_2(G)或表面吸附的S原子、Ni或Ce硫化物有关。在热力学平衡计算的基础上，分析了不同硫氧化态的共存与温度的关系。实验结果和计算结果之间的偏差很可能是由于一些中间氧化步骤的速度限制，以及计算中使用的化学计量比CeO2和部分还原的Ce0.9Gd0.1O2−δ之间的差异。
Sulphur poisoning of nickel–based solid oxide fuel cell (SOFC) anode catalysts is a well-documented shortcoming, but not yet fully understood. Here, a novel experiment is demonstrated to obtain spectroscopic information atoperandoconditions, in particular the molecular structure of sulphur species in the sulphur K-shell X-ray absorption near edge structure (XANES) region for a SOFC anode under realisticoperandoconditions, thus, with the flux of O2−from cathode to anode. Cooling fromT= 550 °C stepwise down to 250 °C, 5 ppm H2S/H2reacting with Ni-gadolinium doped ceria (GDC) anode resulted in several sulphur species in different oxidation states (6+, 4+, 0, −2) and in amounts being at a minimum at high temperature. According to sulphur speciation analysis, the species could either relate to –SO42−or SO3(g), –SO32−or SO2(g), S2(g) or surface-adsorbed S atoms, and, Ni or Ce sulphides, respectively. The coexistence of different sulphur oxidation states as a function of temperature was analysed in the context of thermodynamic equilibrium calculations. Deviations between experimental results and calculations are most likely due to limitations in the speed of some intermediate oxidation steps as well as due to differences between stoichiometric CeO2used in calculations and partially reduced Ce0.9Gd0.1O2−δ.
影响因子：
9.2
作者：
Brightman, E.;Ivey, D. G.;Brandon, N. P.
通讯作者：
Brandon, N. P.
影响因子：
15
作者：
Sarangi, Ritimukta;George, Serena DeBeer;Solomon, Edward I.
通讯作者：
Solomon, Edward I.