Controlled pH precipitation synthesis and antibacterial activity of Ag1.92Mo3O101H2O crystals

• Pristine Ag 1.92 Mo 3 O 10 1H 2 O crystals were obtained by the precipitation method • Rietveld refinement data and cluster coordination for Ag 1.92 Mo 3 O 10 1H 2 O crystals • Ag 1.92 Mo 3 O 10 1H 2 O exhibit highly distorted octahedral Ag 2 O 6 /Mo 1 O 6 clusters • Ag 1.92 Mo 3 O 10 1H 2 O shows a ∼50% drop in antibacterial activity after photoactivation Ag 1.92 Mo 3 O 10 1H 2 O (AMO1H) crystals were synthesized using a controlled precipitation method in which strict acidic pH regulation (pH ≈ 3) was essential to stabilize the desired phase. The crystalline material was characterized by X-ray diffraction with Rietveld refinement, Raman spectroscopy, Fourier transform infrared spectroscopy, and ultraviolet–visible diffuse reflectance spectroscopy, confirming the formation of a highly pure orthorhombic structure composed of hexacoordinated molybdenum–oxygen clusters and an electronic configuration suitable for visible-light activation. Field-emission scanning electron microscopy revealed agglomerated rod-like crystals whose morphology reflects the growth pathway under controlled precipitation conditions. Antibacterial assays demonstrated moderate inhibitory activity in the absence of light, with selectivity toward both Gram-positive and Gram-negative bacteria. Under visible-light irradiation, however, the bactericidal performance increased substantially due to photoinduced processes that promote the formation of silver nanoparticles on the AMO1H crystal surface and enhance reactive species generation. This photoactivation effect significantly improved bacterial elimination efficiency, reaching increases of up to 200%. Overall, the results demonstrate that controlled precipitation with precise pH regulation is an effective strategy for tailoring the structural and functional properties of AMO1H crystals, enabling enhanced antibacterial responses against clinically relevant pathogens such as Escherichia coli, Streptococcus agalactiae, and Pseudomonas aeruginosa. In-depth characterization of the structural, optical, and morphological properties of Ag 1.92 Mo 3 O 10 1H 2 O crystals synthesized through precisely controlled precipitation. This research explores their unique cluster coordination and highlights their remarkable antibacterial properties under WLED illumination.