Silver nanostructure-loaded starch functionalized magnetite (Ag/s-Fe3O4) photocatalyst for H2O2 production: experimental and molecular dynamics studies

Abstract

The present research investigates photocatalytic H2O2 formation on a composite of Ag and starch-stabilized Fe3O4 (denoted as s-Fe3O4) nanoparticles. Starch functionalization of the Fe3O4 part significantly improved the hydrophilicity of the composite. The charge carrier separation efficiency and photocatalytic activity changed with the amount of Ag loading on s-Fe3O4. H2O2 production on this photocatalyst was investigated in pure water and aqueous solutions of various green sacrificial agents like glycerol. Classical molecular dynamics (MD) was employed to study the adsorption affinity of O2 and H2O on the surface of Fe3O4, s-Fe3O4, and Ag/s-Fe3O4 in an aqueous medium. MD results indicate that functionalizing Fe3O4 with starch (s-Fe3O4 system) enhances water adsorption affinity, and precipitating Ag nanostructures on s-Fe3O4 (Ag/s-Fe3O4) increases O2 adsorption affinity. Water contact angle measurements on Fe3O4, s-Fe3O4, and Ag/s-Fe3O4 nanoparticles also quantify significantly better water adsorption due to starch functionalization. An aqueous solution of glycerol exhibited the best photocatalytic H2O2 production activity. This result is critical given that glycerol is green, economical, and a byproduct of the biodiesel industry. A photocatalysis mechanism for H2O2 generation on Ag/s-Fe3O4 photocatalysts has been proposed based on a series of control experiments and molecular dynamics simulations. © 2025 The Royal Society of Chemistry.