Interaction between V₂O₅ nanowires and high pressure CO₂ gas up to 45 bar: Electrical and structural study

In the oxidative dehydrogenation (ODH) process that converts ethylbenzene to styrene, vanadium-based catalysts, especially V₂O₅, are used in a CO₂ atmosphere to enhance process efficiency. Here we demonstrate that the activation energy of V₂O₅ can be manipulated by exposure to high pressure CO₂, using V₂O₅ nanowires (VON). The oxidation of V⁴⁺ to V⁵⁺ was observed by X-ray photoelectron spectroscopy. The ratio of V⁴⁺/V⁵⁺ which the typical comparable feature decreased 73.42%. We also found an increase in the interlayer distance in VON from 9.95 Å to 10.10 Å using X-ray diffraction patterns. We observed changes in the peaks of the stretching mode of bridging triply coordinated oxygen (V₃-O), and the bending vibration of the bridging V-O-V, using Raman spectroscopy. We confirmed this propensity by measuring the CO₂ pressure-dependent conductance of VON, up to 45 bar. 92.52% of decrease in the maximum conductance compared with that of the pristine VON was observed. The results of this study suggest that ODH process performance can be improved using the VON catalyst in a high pressure CO₂ atmosphere.