Biogas as a fuel for solid oxide fuel cells and synthesis gas production: effects of ceria-doping and hydrogen sulfide on the performance of nickel-based anode materials.
Biogas as a fuel for solid oxide fuel cells and synthesis gas production: effects of ceria-doping and hydrogen sulfide on the performance of nickel-based anode materials.
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DOI：
10.1039/c0dt01373k
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发表时间：
2011-05
影响因子：
4
通讯作者：
C. J. Laycock;J. Staniforth;R. Mark Ormerod
中科院分区：
文献类型：
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作者：
C. J. Laycock;J. Staniforth;R. Mark Ormerod
人们对通过 Ni/YSZ 阳极金属陶瓷催化剂将沼气转化为合成气（H(2) + CO 的混合物）进行了大量研究。沼气是一种可变的气体混合物，主要由甲烷和二氧化碳组成（通常比例为 2:1，但因来源而异），其他成分包括含硫气体，如硫化氢，可导致镍催化剂硫中毒。通过在 750-1000 °C 温度范围内，在存在和不存在 H(2)S 的情况下，对富甲烷 (2:1) CH(4)/CO(2) 混合物进行一系列催化反应，研究了温度对沼气转化条件下 90 : 10 mol% Ni/YSZ 的碳沉积和硫中毒的影响。通过在二氧化铈掺杂的 Ni/YSZ 上进行类似的一系列反应，还研究了二氧化铈掺杂对二氧化碳重整、碳沉积和耐硫性的影响。以镍含量的5mol％掺杂二氧化铈，得到85.5∶4.5∶10mol％Ni/CeO(2)/YSZ的阳极催化剂组合物。使用四极质谱法（QMS）跟踪反应，并通过对反应后的催化剂样品进行反应后程序升温氧化（TPO）来分析碳沉积量。在未掺杂的 Ni/YSZ 上，碳沉积主要通过甲烷的热分解发生。氧化铈掺杂显着抑制了甲烷分解，同时在高温下促进了逆布杜反应，显着降低了碳沉积。 Ni/YSZ的硫中毒发生在两个相中，第一相引起的活性损失最多，并且随着反应温度的升高而加速，而第二相具有更大的稳定性并且随着反应温度的升高变得更加有利。添加H(2)S可显着抑制甲烷分解，从而大大减少碳沉积。氧化铈掺杂显着提高了Ni/YSZ的耐硫性，然而，在H(2)S存在下，氧化铈不会促进逆布杜反应，并且在高温下碳沉积比氧化铈掺杂的Ni/YSZ更大。为了进一步研究二氧化铈掺杂的影响，采用二氧化铈阳极金属陶瓷构建了固体氧化物燃料电池（SOFC），并测试了其在模拟沼气和氢气上的电性能。该燃料电池随后使用模拟沼气运行 1000 小时，其整体电气性能没有下降。
Numerous investigations have been carried out into the conversion of biogas into synthesis gas (a mixture of H(2) + CO) over Ni/YSZ anode cermet catalysts. Biogas is a variable mixture of gases consisting predominantly of methane and carbon dioxide (usually in a 2 : 1 ratio, but variable with source), with other constituents including sulfur-containing gases such as hydrogen sulfide, which can cause sulfur poisoning of nickel catalysts. The effect of temperature on carbon deposition and sulfur poisoning of 90 : 10 mol% Ni/YSZ under biogas conversion conditions has been investigated by carrying out a series of catalytic reactions of methane-rich (2 : 1) CH(4)/CO(2) mixtures in the absence and presence of H(2)S over the temperature range 750-1000 °C. The effect of ceria-doping on carbon dioxide reforming, carbon deposition and sulfur tolerance has also been investigated by carrying out a similar series of reactions over ceria-doped Ni/YSZ. Ceria was doped at 5 mol% of the nickel content to give an anode catalyst composition of 85.5 : 4.5 : 10 mol% Ni/CeO(2)/YSZ. Reactions were followed using quadrupolar mass spectrometry (QMS) and the amount of carbon deposition was analysed by subjecting the reacted catalyst samples to a post-reaction temperature programmed oxidation (TPO). On undoped Ni/YSZ, carbon deposition occurred predominantly through thermal decomposition of methane. Ceria-doping significantly suppressed methane decomposition and at high temperatures simultaneously promoted the reverse Boudouard reaction, significantly lowering carbon deposition. Sulfur poisoning of Ni/YSZ occurred in two phases, the first of which caused the most activity loss and was accelerated on increasing the reaction temperature, while the second phase had greater stability and became more favourable with increasing reaction temperature. Adding H(2)S significantly inhibited methane decomposition, resulting in much less carbon deposition. Ceria-doping significantly increased the sulfur tolerance of Ni/YSZ, however, in the presence of H(2)S ceria did not promote the reverse Boudouard reaction and at high temperatures carbon deposition was greater over ceria-doped Ni/YSZ. In order to further study the effects of ceria-doping, a solid oxide fuel cell (SOFC) was constructed with a ceria-doped anode cermet and its electrical performance on simulated biogas compared to hydrogen was tested. This fuel cell was subsequently ran for 1000 h on simulated biogas with no degradation in its overall electrical performance.