A facile exfoliation-crystal growth route to multicomponent Ag₂CO₃/Ag-Ti₅NbO₁₄ nanohybrids with improved visible light photocatalytic activity

Abstract

Multicomponent Ag2CO3/Ag-layered Ti5NbO14 nanohybrids are synthesized by the crystal growth of silver carbonate on the surface of exfoliated layered titanoniobate 2D nanosheets. In the obtained nanohybrids, the spherical Ag2CO3 nanoparticles with a size of 5-10 nm are immobilized on the surface of the titanoniobate nanosheets with partial formation of neutral Ag metal caused by electron transfer from anionic titanoniobate nanosheets to silver cations. An electronic coupling between Ag2CO3/Ag and Ti5NbO14 nanosheets leads to a remarkable enhancement of visible light absorption and a significant depression of electron-hole recombination. The present Ag2CO3/Ag-layered Ti5NbO14 nanohybrids show much higher visible light photocatalytic activity than the unhybridized Ag2CO3, underscoring the beneficial effect of hybridization with metal oxide nanosheets on the photocatalytic activity of silver oxosalts. Before and after the photoreaction, the crystal structure and crystal morphology of the Ag2CO3/Ag-layered Ti5NbO14 nanohybrids remain unchanged, highlighting the excellent photostability of these materials. All the present experimental findings clearly demonstrate the usefulness of the exfoliation-crystal growth method in exploring novel efficient visible light active photocatalysts.

Application of Exfoliated Inorganic Nanosheets for Strongly‐Coupled Hybrid Photocatalysts

“…Among them, the hybridization of two kinds of semiconductors can provide one of the most effective ways to explore efficient visible‐light photocatalysts. As presented in Figure a, both the Ag 2 CO 3 /Ag–layered Ti 5 NbO 14 and Ag 2 CO 3 –N‐doped TiO 2 nanohybrids show much higher photodegradation of 4‐chlorophenol (4‐CP) under visible light than the unhybridized Ag 2 CO 3 because of the strong electronic coupling between Ag 2 CO 3 /Ag and Ti nanosheets . Similarly, a CdS QD@Ag 3 PO 4 nanocomposite exhibits much better photocatalytic degradation of MB and 4‐CP under visible light than the precursors P25, CdS, and Ag 3 PO 4 .…”

“…a) Schematic and photocatalytic activity test of Ag 2 CO 3 /Ag–layered Ti 5 NbO 14 nanohybrids. Reproduced with permission . Copyright 2014, The Royal Society of Chemistry.…”

“…As shown in Figure e, the intervention of a highly conductive nanosheet prevents the electron–hole recombination because this nanosheet attracts photogenerated charge species from the surrounding material by acting as a charge reservoir. As depicted in Figure f, the narrow‐bandgap semiconducting component can function as a light sensitizer in this hybrid system, even if it is not photocatalytically active …”

Ag2CO3/UiO-66(Zr) composite with enhanced visible-light promoted photocatalytic activity for dye degradation

“…[11,13,19,20]. Almost all of these studies aimed to enhance the photocatalytic activity of pristine Ag 2 CO 3 , and a few of them declared that the substrates could also assist in inhibiting the photocorrosion of Ag 2 CO 3 [15,16].…”

“…In spite of the good photocatalytic activity of pristine Ag 2 CO 3 [8][9][10], most of the studies were focusing on diverse substrates supported Ag 2 CO 3 as photocatalysts for water treatment [11][12][13][14].…”