A comprehensive insight into the parameters that influence the synthesis of Ag2MoO4 semiconductors via experimental design.

This study characterized and statistically evaluated the influence of three parameters that potentially affect the synthesis of Ag₂MoO₄, which have not previously been investigated in conjunction. The study focused on the concentration of a dispersant (polyvinylpyrrolidone, PVP, mmol⁻¹), aging time (h), and pH to evaluate the effects of these factors on the physio-chemical properties of the as-produced semiconductors. Particularly, this study aims to better understand the synthesis of metastable α-Ag₂MoO₄, which is poorly studied, and explore how minor modifications to the chosen parameters, under mild conditions, can impact its formation. To optimize the production of the α-phase, eleven Ag₂MoO₄ catalysts were produced by complete factorial experimental design, varying the aforementioned parameters. XRD results revealed that only two samples presented crystalline α-Ag₂MoO₄ and were significantly influenced by PVP concentration, pH, and their interaction. Additionally, prolonged aging favored an α to β transformation, reducing α content from 68 to 8%. These transformations are correlated with the thermodynamic stability of the crystal, which attempts to reach a more stable matrix. Furthermore, acidic pH modified the stabilization of Ag⁺ with PVP, enabling the formation of α-Ag₂MoO₄. The presence of the α phase was further confirmed by TGA/DTA, FTIR, and Raman spectroscopies results. Only PVP concentration significantly affected particle size, increasing it from ~ 4 to 8 μm upon PVP addition. Moreover, several morphologies were observed (butterfly like, potato like, coral like, polygons, etc.), potentially influencing their catalytic and antibacterial activities. Furthermore, a mechanism was proposed to elucidate how these factors affected the particles’ formation. [ABSTRACT FROM AUTHOR]