It is challenging to improve the low-temperature activity of Ni-based catalyst for the CO methanation reaction. In this study, a molybdenum-doped cerium oxide supported Ni catalyst (Ni/MoCe) was constructed, and it showed remarkable CO methanation performance at low temperatures (<300 °C). Structural analysis revealed that the incorporation of Mo into the CeO lattice could enrich the surface oxygen vacancies, reduce the particle size of Ni species and enhance the metal-support interaction. The Ni/MoCe demonstrated a faster HCOO* pathway for the conversion of CO to CH compared with Ni/CeO. Besides, the rich surface oxygen vacancies in Ni/MoCe facilitated the adsorption form of bidentate carbonates and the enhanced Ni-CeO interaction reduced the approach resistance of active H species from Ni for subsequent hydrogenation process. This work proves that Mo doping is an effective vacancy engineering strategy to design high-performance heterogeneous catalysts for CO hydrogenation.

中文翻译：

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钼掺杂促进 CeO2 表面氧空位，增强 Ni-CeO2 催化剂上的低温 CO2 甲烷化

提高CO甲烷化反应镍基催化剂的低温活性具有挑战性。本研究构建了一种钼掺杂氧化铈负载镍催化剂（Ni/MoCe），它在低温（<300℃）下表现出优异的CO甲烷化性能。结构分析表明，将Mo掺入CeO晶格可以丰富表面氧空位，减小Ni物种的粒径并增强金属-载体相互作用。与 Ni/CeO 相比，Ni/MoCe 表现出更快的 HCOO* 途径将 CO 转化为 CH。此外，Ni/MoCe中丰富的表面氧空位有利于二齿碳酸盐的吸附形式，增强的Ni-CeO相互作用降低了Ni中活性H物种对后续加氢过程的接近阻力。这项工作证明Mo掺杂是设计高性能CO加氢多相催化剂的有效空位工程策略。