Hydrothermal Preparation of Ag/Ag_1.69Sb_2.27O_6.25 Sesame‐Hollow‐Ball‐Type Nanocomposites: The Formation Mechanism of Metallic Ag in the Ag‐H₂O System at 400 K

Abstract

Ag/Ag1.69Sb2.27O6.25 sesame-hollow-ball-type nanocomposites were prepared via a facile one-step hydrothermal method at 400 K. Power X-ray diffraction analysis shows that all diffraction peaks were well consistent with JCPDS card no: 89-6552 of Ag1.69Sb2.27O6.25. Scanning electron microscopy and high-resolution transmission electron microscopy images of the composites indicate that some smaller metallic Ag particles with size∼18.3 nm uniformly dense on the surface of Ag1.69Sb2.27O6.25 hollow nanospheres with a mean size of about 170 nm, producing Ag/Ag1.69Sb2.27O6.25 hollow-sesame-ball nanocomposites. The surface chemical state of Ag/Ag1.69Sb2.27O6.25 is investigated by XPS, and all peaks of Ag 3d, O 1s, and Sb 3d show their different chemical states. The BET surface area of the sample is 7.268 m2/g, and the pore sizes of nanocomposites are more than 5 nm. The light absorption property of as-prepared materials is studied by UV-vis/DRS, and the adsorption band is located at 445 nm, and the estimated energy band gap (Eg) is 2.55 eV. The calculated partial φ-pH diagrams in the Ag-H2O system at 400 K predict that the Ag+ ion can react with H2 to form metallic Ag.

Hydrothermal Synthesis and Photocatalytic Properties of Graphene@Ag/AgSb2O5.8 Composites: Reaction Laws of the Composites in Sintering Process

“…Firstly, lots of tiny AgSb 2 O 5.8 crystal nuclei are formed by the reaction (equation ( 1)) between S b O 6 H 6 -(dissociated from potassium pyroantimonate) and Ag + (dissociated from silver nitrate) and preferentially adsorb on the interface on the graphene. Some Ag crystal nuclei can be reduced from Ag + in a hydrothermal reaction system (equation ( 2)) [35] and gather on the surface of AgSb 2 O 5.8 particles. Both were aged in a Teflon-lined stainless-steel autoclave after stirring and aging.…”

“…As a comparison, silver antimonate was also prepared by a hydrothermal route like our previous reports [35].…”