Three-Dimensional gelatinous Network-Tailored magnetic Fe3O4@Ag6Si2O7 heterostructures for efficient Visible-Light-Driven water remediation

Severe agglomeration of spherical magnetic photocatalysts can restrict accessible surface area and catalyst recovery. Here, a tailored sol–gel protocol followed by interfacial thiolation was used to construct a three-dimensional gelatinous Fe 3 O 4 @Ag 6 Si 2 O 7 heterostructure (3D-Gel-Fe 3 O 4 @Ag 6 Si 2 O 7 ). The network exhibited a BET surface area of 40.69 m 2 g –1 and an average pore diameter of 22.6 nm, both higher than those of the spherical controls. Optical, photoluminescence, and photocurrent measurements were consistent with altered interfacial charge-transfer behavior, although they did not uniquely establish a specific carrier-transfer pathway. Under the tested visible-light conditions, the 3D-Gel catalyst achieved 96.4% total RhB decolorization after 180 min, including the contribution from dark adsorption, with an apparent pseudo-first-order rate constant of 0.0144 min –1 . This rate constant was 1.47 and 1.11 times those of the Pre-Sph and Post-Sph controls, respectively. After five cycles, the final decolorization efficiency was 90.1%, and the saturation magnetization was 53.13 emu g –1 . These results associate the network morphology with increased accessible surface area, RhB removal, and magnetic recoverability under the tested conditions.