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چکیده
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MoV-based composites stand out as the most promising potential catalysts tar- geted for direct production of acrylic acid from alkane/alkene substances. Herein, MoVTeNbO powder was synthesized and successfully fabricated by adding graphite as an appropriate tableting agent. Without employing graphite as lubricant, the fabrication of tablets was not practicable. The physicochemi- cal effects of graphite on the catalyst properties were investigated via charac- terization by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), scanning electron microscopy (SEM), ammonia temperature-programmed desorption (NH 3-TPD), and thermal gravimetric analysis (TGA) methods. In addition to the easy and operative formation of tablets by consisting graphite, TGA results indicated better thermal stability compared to the bare powder. No harmful impact of graphite on the catalyst crystalline phases and morphol- ogy was detected by XRD and SEM analysis. The SEM images proved the graphite incorporation as a binder in the physical combination of the catalyst particles along the compression process, resulting in the desired physical resis- tance. Graphite caused a slight decrease in the BET surface area and final cata- lyst acidity. Despite the effect of reducing propene conversion, interestingly, a substantial improvement in the yield of acrylic acid was found by tableting. The graphite as an inert agent suppressed hot spots on the catalyst surface, leading to superior consistency in activity over time as well as lower selectivity to undesirable COx .
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