Bifunctional TiO₂/Ag₃PO₄/graphene composites with superior visible light photocatalytic performance and synergistic inactivation of bacteria

Abstract

In this work, bifunctional TiO 2 /Ag 3 PO 4 /graphene (GR) composites have been prepared via the combination of ion-exchange method and hydrothermal approach, and the fabrication of "pizza-like" three-phase TiO 2 / Ag 3 PO 4 /GR composites has been achieved through the electrostatic-driven assembly of positively-charged Ag + on negatively-charged graphene oxide (GO) sheets, followed by the nucleation & controlled growth of Ag 3 PO 4 and the deposition of Degussa P25 on the GO surface. Consequently, the hydrothermal treatment leads to the generation of TiO 2 /Ag 3 PO 4 /GR composites with well-defined structures. The as-prepared composites exhibited highly efficient visible light photocatalytic activity toward organic dye molecule degradation and showed excellent bactericidal performance. This is the first report on the production of bifunctional three-phase metal oxide-Ag 3 PO 4 -GR composite materials with improved photocatalytic and antibacterial properties. The improved photocatalytic activity is attributed to the effective separation of photoexcited electron-hole pairs and fast charge transfer between components in the composite, while its excellent bactericidal performance is believed to come from intrinsic bacterial inactivation of Ag 3 PO 4 and photo-induced antibacterial activity of active oxygen-containing radicals generated in the irradiated system. The proper molar ratio of Ag 3 PO 4 /TiO 2 and the added amount of GO in the precursor have been considered to play crucial roles in the formation of bifunctional composites with promising properties. The TiO 2 /Ag 3 PO 4 /GR composite significantly decreases the percentage of expensive Agcontaining material while it reveals better photocatalytic and antibacterial performance than Ag 3 PO 4 , providing new insights into the low-cost, large-scale production of Ag 3 PO 4 -based function materials for practical applications.

Hydroxyapatite/N-doped carbon dots/Ag3PO4 composite for improved visible-light photocatalytic performance

“…To solve the limitations of Ag 3 PO 4 , hybrid photocatalysts have been proposed. 13,14,22,[36][37][38][39][40] Among them, Zhang et al 22 reported that coupling Ag 3 PO 4 with CDs was an effective strategy to improve the stability of Ag 3 PO 4 , since the dissolution of Ag 3 PO 4 could be impeded by CDs. Hong et al 13 and Chai et al 14 also pointed out hydroxyapatite supported Ag 3 PO 4 prepared via in situ ionexchange method could effectively reduce the cost and improve the photocatalytic activity of the composite.…”

Ag3PO4-TiO2-Graphene Oxide Ternary Composites with Efficient Photodegradation, Hydrogen Evolution, and Antibacterial Properties

“…The XRD patterns of the APTGO ternary composites are displayed in Figure 1 4 , respectively. They demonstrate the presence of Ag 3 PO 4 in the APTGO composites [37,38]. Nevertheless, there is no characteristic peak of GO observed in Figure 1.…”

The Role of Graphene Oxide in Ag3PO4/graphene Oxide Composites for Enhanced Visible-light-driven Photocatalytic Ability

“…The sharp peak is located at 908 cm -1 corresponding to the PO 4 3-symmetric stretching vibration. The higher wave number band at 1002 cm -1 is assigned to the movement of terminal oxygen bond vibrations in phosphate chains, and the broad peak centered at 1132 cm -1 due to symmetric stretch of O-P-O bonds (32)(33)(34). After the incorporation of G 0 and G 24 , the Raman spectra of S 0 and S 24 are similar to the Ag 3 PO 4 , however, there are other two prominent peaks in the spectra which represent the nature of graphene edges (D band) and the degree of the ordered graphite (G band), respectively (35).…”