In this work, we integrated Ag3PO4 with Bi4Ti3O12 to form Bi4Ti3O12/Ag3PO4 heterojunction nanocomposites by an ion-exchange method. The as-prepared Bi4Ti3O12/Ag3PO4 composites were systematically characterized by means of XRD, SEM, TEM, BET, XPS, UV-vis DRS, EIS, PL spectroscopy, and photocurrent response. SEM, TEM, and XPS results demonstrate the creation of Bi4Ti3O12/Ag3PO4 heterojunction with obvious interfacial interaction between Bi4Ti3O12 and Ag3PO4. PL spectra, EIS spectra, and photocurrent responses reveal that the composites display an enhanced separation efficiency of photogenerated electron-hole pairs, which is due to the charge transfer between Bi4Ti3O12 and Ag3PO4. Rhodamine B (RhB) was chosen as the target organic pollutant to evaluate its degradation behavior over Bi4Ti3O12/Ag3PO4 composites under simulated sunlight irradiation. Compared to bare Bi4Ti3O12 and Ag3PO4 nanoparticles, the composites exhibit a significantly enhanced photocatalytic activity. The highest photocatalytic activity is observed for the 10% Bi4Ti3O12/Ag3PO4 composite with 10% Bi4Ti3O12 content, which is about 2.6 times higher than that of bare Ag3PO4. The photocatalytic mechanism involved was investigated and discussed in detail.

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A carbon quantum dot (CQDs)/Ag3PO4/BiPO4 heterostructure photocatalyst was constructed by a simple hydrothermal synthesis method. The as-prepared CQDs/Ag3PO4/BiPO4 photocatalyst has been characterized in detail by X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible spectroscopy, and photoelectrochemical measurements. It is demonstrated that the CQDs/Ag3PO4/BiPO4 composite is constructed by assembling Ag3PO4 fine particles and CQDs on the surface of rice-like BiPO4 granules. The CQDs/Ag3PO4/BiPO4 heterostructure photocatalyst exhibits a higher photocatalytic activity for the degradation of the rhodamine B dye than that of Ag3PO4, BiPO4, and Ag3PO4/BiPO4. The synergistic effects of light absorption capacity, band edge position, separation, and utilization efficiency of photogenerated carriers play the key role for the enhanced photodegradation of the rhodamine B dye.

Based on a sonochemical route, the effect of trisodium citrate and acetic acid, which served as the structure-directing agents, on the synthesis of Ag 3 PO 4 nano/micro structures was investigated. It is found that the sample prepared at n(AgNO 3 ) = 3 mmol, n(KH 2 PO 4 ) = 2 mmol, n(Na 3 Cit) = 1 mmol and n(CH 3 COOH) = 3 mL is composed of coral-like microspheres. When varying the contents of reagents to other levels or in the absence of acetic acid, it brings about the formation of mesoporous microspheres or polyhedrons. The photocatalytic activity of the as-prepared Ag 3 PO 4 samples was evaluated by the degradation of rhodamine B (RhB) under simulated-sunlight irradiation. Compared to the mesoporous microspheres or polyhedrons, the coral-like microspheres exhibit a superior photocatalytic activity, and the degradation percentage of RhB after photocatalysis reaction for 60 min reaches 96.8%.

Ag 3 PO 4 nanospheres with an average size of 300 nm were synthesized via a sonochemical process. The electrochemical performances of the as-synthesized Ag 3 PO 4 nanospheres in aqueous KOH electrolyte with different concentrations were investigated by cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy. The measured cyclic voltammetry curves as well as charge-discharge curves reveal a good pseudocapacitive behavior of Ag 3 PO 4 nanospheres. In a 1 M KOH electrolyte at a current density of 0.5 mA cm −2 , the speci c capacitance of Ag 3 PO 4 nanospheres is obtained to be 832 F g −1. However, Ag 3 PO 4 nanospheres exhibit an inferior charge-discharge cycling stability, which could be due to the formation of Ag 2 O during the cycling process.