Construction of Bi2Sn2O7/Ag/Ag3PO4 heterojunction and its photocatalytic degradation properties

• The Bi 2 Sn 2 O 7 /Ag/Ag 3 PO 4 Z-scheme heterojunctions were reasonably constructed. • The photocatalytic efficiency of optimal Bi 2 Sn 2 O 7 /Ag/Ag 3 PO 4 was enhanced. • The main photocatalytic reactive species are h + and·O 2 − . • The photocatalytic mechanism of the Z-scheme Bi 2 Sn 2 O 7 /Ag/Ag 3 PO 4 was proposed. The construction of heterojunction photocatalysts with excellent redox ability is considered as an effective strategy to address refractory pollutants. The novel Bi 2 Sn 2 O 7 /Ag/Ag 3 PO 4 Z-scheme heterojunctions were designed and constructed by a hydrothermal combined precipitation method. The Ag 3 PO 4 microspheres were simply precipitated and supported the nanoparticles Bi 2 Sn 2 O 7 , and then Ag + cations on the surface were photoreduced to Ag 0 nanoparticles anchored on the surface of Ag 3 PO 4 . Under visible light irradiation, the catalyst 0.4-Bi 2 Sn 2 O 7 /Ag/Ag 3 PO 4 with m(Bi 2 Sn 2 O 7 ):m(Ag 3 PO 4 )= 0.4:1.0 mass ratio has the highest Rhodamine B degradation efficiency of 98.2% in 80 min, which is 8.3 and 4.2 folds higher than that of Bi 2 Sn 2 O 7 and Ag 3 PO 4 , respectively. Besides, Bi 2 Sn 2 O 7 /Ag/Ag 3 PO 4 possessed the effectively degradation of xylenol orange (XO) and Cr (Ⅵ). The results of the radical scavengers reveal that h + and·O 2 − act as the main photocatalytic reactive specie. The photocatalytic mechanism over Z-scheme Bi 2 Sn 2 O 7 /Ag/Ag 3 PO 4 has been proposed based on the experimental results together with the ultraviolet photoelectron spectroscopy (UPS) analysis and scavenger reactions.