ساخت نانوپولك هاي اكسيد موليبدن به روش شعله و پوشش دهي با پالاديوم كلريد براي حسگر هيدروژن

In this study, eight molybdenum oxide (MoO₃) nanostructured samples were fabricated using the flame vapor deposition method, with precise control of the substrate temperature over a range from room temperature to 550 °C, an‎d were coated with palladium(II) chloride (PdCl₂). The aim of this research was to develop an‎d eva‎luate the performance of these structures as hydrogen sensors. The samples were characterized using microscopic an‎d structural techniques, including field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), an‎d Raman spectroscopy. The convergence of the results obtained from these analyses revealed a morphological evolution from porous agglomerated particles to interconnected an‎d nanofibrous structures, which became more pronounced with increasing deposition temperature. Surface modification with palladium resulted in enhanced interparticle connectivity an‎d improved catalytic activity; these structural changes directly affected the sensing performance. Gas-sensing tests were conducted under various operating conditions, including different operating temperatures, different hydrogen concentrations, including 10%, an‎d different humidity levels. Parameters such as sensitivity, response an‎d recovery times, selec‎tivity, an‎d long-term stability were recorded an‎d analyzed. The results demonstrated high sensitivity, rapid response an‎d recovery, favorable selec‎tivity toward interfering gases, an‎d good operational stability. The best sensing performance was obtained for the sample deposited at 550 °C an‎d operated at 300 °C, which was attributed to the synergistic effect of appropriate crystallinity, nanostructured morphology, an‎d the catalytic activity of Pd. Furthermore, the flame vapor deposition method was introduced as a practical approach for producing sensing samples owing to its high production rate, operational simplicity, cost-effectiveness, an‎d scalability. The findings indicate that the Pd–MoO₃ nanostructures fabricated by the flame method have considerable potential for hydrogen detection in practical applications.

مهدي رنجبر , پيمان صاحب سرا

پرويز كاملي

حميده شاكري پور , كاظم كرمي