反应气中活化后的镍酸镧用于二氧化碳加氢生成甲烷

采用柠檬酸法制备了钙钛矿镍酸镧，并将其作为催化剂的前躯体用于二氧化碳甲烷化反应中。催化剂在400℃~700℃温度下反应气中进行活化处理。活化过程中生成了金属镍颗粒和碳酸氧化镧。金属镍呈高度分散状并被碳酸氧化镧包裹，这种现象有助于反应在400℃和500℃的高温下仍保持高活性和稳定性。XRD、XPS、TEM和H₂-TPD等表征测试表明，在活化过程中生成的碳酸氧化镧对反应起到了至关重要的作用。

Methanation of carbon dioxide over the LaNiO3 perovskite catalysts activated under the reactant stream

In this study, LaNiO₃ perovskite catalysts were prepared by citrate method and used for carbon dioxide (CO₂) methanation. The catalysts were activated at different temperatures (400℃~700℃) under the reactant stream. The activation led to the formation of small metallic nickel particles and hexagonal lanthanum oxocarbonate (La₂O₂CO₃). Ni0 was highly dispersed and enveloped by La₂O₂CO₃, which was responsible for the high catalytic activity and stability of the LaNiO₃ perovskite catalysts even at high temperature (400℃~500℃). The X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and H₂-temperature-programmed desorption measurements illustrated that La₂O₂CO₃ generated from the activation might play an important role in the methanation of CO₂.