Understanding the carbon-tolerant mechanisms from a microscopic view is of special importance to develop proper anodes for solid oxide fuel cells. In this work, we employed density-functional theory calculations to study the CH₄ reaction mechanism over a Ni/TiO₂ nanostructure, which experimentally demonstrated good carbon tolerance. Six potential pathways for methane reforming reactions were studied over the Ni/TiO₂(110) surface under both dry and wet atmospheres, and the main concerns were focused on the impact of TiO₂ and Ni/TiO₂ interface on CO/H2 formation. Our calculations suggest that the reaction between carbon and the interfacial lattice oxygen to form CO* is the dominant pathway for CH₄ reforming under both dry and wet atmospheres, and intervention of steam directly to oxidize C* with its dissociated OH* group is less favorable in energy than that to wipe off oxygen vacancy to get ready for next C* oxidation. In all investigated paths, desorption of CO* is one of the most difficult steps. Fortunately, CO* desorption can be greatly promoted by the large heat released from the previous CO* formation process under wet atmosphere. H₂O adsorption and dissociation over the TiO₂ surface are found to be much easier than those over Ni, yttria stabilized zirconia (YSZ) and CeO₂, which should be the key reason for the greatly depressed carbon deposition over Ni-TiO₂ particles than traditional YSZ-Ni and CeO₂-Ni anode. Our study presents the detailed CO* formation mechanism in CH₄ reforming process over the Ni/TiO₂ surface, which will benefit future research for exploring new carbon-tolerant solid oxide fuel cell anodes.

从微观角度了解耐碳机理对于开发用于固体氧化物燃料电池的合适阳极特别重要。在这项工作中，我们采用密度泛函理论计算来研究Ni / TiO ₂纳米结构上的CH ₄反应机理，并通过实验证明了良好的碳耐受性。研究了在干燥和潮湿气氛下，Ni / TiO ₂（110）表面甲烷重整反应的六个潜在途径，主要关注的是TiO ₂和Ni / TiO ₂界面对CO / H2形成的影响。我们的计算表明，碳与界面晶格氧之间形成CO *的反应是CH ₄的主要途径在干燥和潮湿的气氛下进行重整，以及直接用蒸汽分解其OH *离解基团氧化C *的能量，都比消除氧空位为下一次C *氧化做准备的能量不利。在所有研究途径中，CO *的解吸是最困难的步骤之一。幸运的是，先前的CO *形成过程在潮湿气氛下释放的大量热量可以大大促进CO *的解吸。发现H ₂ O在TiO ₂表面上的吸附和解离要比Ni，氧化钇稳定的氧化锆（YSZ）和CeO _2上的吸附和解离容易得多，这应该是Ni-TiO ₂颗粒上碳沉积大大降低的关键原因。比传统的YSZ-Ni和CeO ₂-镍阳极。我们的研究提出了在Ni / TiO ₂表面上CH ₄重整过程中详细的CO *形成机理，这将有助于将来探索新的耐碳固体氧化物燃料电池阳极的研究。