Vanadium and its surface oxides were studied as a potential nitrogen-selective membrane material for indirect carbon capture from coal or natural gas power plants. The effects of minor flue gas components (SO₂, NO, NO₂, H₂O, and O₂) on vanadium at 500–600 °C were investigated by thermochemical exposure in combination with X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and in situ X-ray diffraction (XRD). The results showed that SO₂, NO, and NO₂ are unlikely to have adsorbed on the surface vanadium oxides at 600 °C after exposure for up to 10 h, although NO and NO₂ may have exhibited oxidizing effects (e.g., exposure to 250 ppmv NO/N₂ resulted in an 2.4 times increase in surface V₂O₅ compared to exposure to just N₂). We hypothesize that decomposition of surface vanadium oxides and diffusion of surface oxygen into the metal bulk are both important mechanisms affecting the composition and morphology of the vanadium membrane. The results and hypothesis suggest that the carbon capture performance of the vanadium membrane can potentially be strengthened by material and process improvements such as alloying, operating temperature reduction, and flue gas treatment.

中文翻译：

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钒作为碳捕集的潜在膜材料：次要烟气物种的影响

钒及其表面氧化物已被研究为一种潜在的氮选择性膜材料，可用于从燃煤或天然气发电厂间接捕集碳。通过热化学暴露结合X射线光电子能谱（XPS）进行扫描，研究了500-600°C下微量烟气成分（SO ₂，NO，NO ₂，H ₂ O和O ₂）对钒的影响。电子显微镜（SEM）和原位X射线衍射（XRD）。结果表明，暴露10个小时后，在600°C下，SO ₂，NO和NO ₂不太可能吸附在表面钒氧化物上，尽管NO和NO ₂可能表现出氧化作用（例如，暴露于250 ppmv NO / N ₂导致表面V ₂ O ₅相比暴露于N _2而言增加了2.4倍）。我们假设表面钒氧化物的分解和表面氧向金属主体的扩散都是影响钒膜组成和形态的重要机制。结果和假设表明，钒膜的碳捕获性能可以通过材料和工艺改进（例如合金化，降低工作温度和烟道气处理）来增强。