Round-the-clock photocatalysis of plasmonic Ag-enhanced Z-scheme heterojunction material Sr2MgSi2O7:(Eu, Dy)/g‑C3N4@Ag under visible-light irradiation

Self-luminous plasmonic photocatalysts Sr2MgSi2O7:(Eu, Dy)/g-C3N4@Ag were prepared using high-temperature sintering and photodeposition. Compared with pristine g-C3N4, the energy storage property of the long-afterglow luminescent material Sr2MgSi2O7:(Eu, Dy) and the noble metal Ag with localized surface plasmon resonance effect enable the composites to perform more excellent in round-the-clock photocatalytic degradation. The improved photocatalytic performance is attributed to the formation of Z-scheme heterojunction by Sr2MgSi2O7:(Eu, Dy) and g-C3N4, and to the fact that the loaded Ag nanoparticles broaden their visible-light absorption range and enable faster carrier transfer and more productive separation of electron-hole (e−-h+) pairs. According to various characterization outcomes and density functional theory calculations, possible pathways for electrons transfer during the photocatalytic reaction and possible mechanisms for the increasing of photocatalytic performance of Sr2MgSi2O7:(Eu, Dy)/g-C3N4@Ag composites are proposed. This work provides a targeted way for the optimization of round-the-clock heterojunction photocatalysts.