Enhanced solar-light-driven photocatalytic properties of novel Z-scheme binary BiPO_(4)nanorods anchored onto NiFe_(2)O_(4)nanoplates:Efficient removal of toxic organic pollutants

Global environmental problems have been increasing with the growth of the world economy and have become a crucial issue.To replace fossil fuels,sustainable and eco-friendly catalysts are required for the removal of organic pollutants.In this study,nickel ferrite(NiFe_(2)O_(4))was prepared using a simple wet-chemical synthesis,followed by calcination;bismuth phosphate(BiPO_(4))was also prepared using a hydrothermal method.Further,NiFe_(2)O_(4)/BiPO_(4)nanocomposites were prepared using a hydrothermal technique.Numerous characterization studies,such as structural,morphology,surface area,optical,photoluminescence,and photoelectrochemical investigations,were used to analyze NiFe_(2)O_(4)/BiPO_(4)nanocomposites.The morphology analysis indicated a successful decoration of BiPO_(4)nanorods on the surface of Ni Fe_(2)O_(4)nanoplate.Further,the bandgap of the NiFe_(2)O_(4)/BiPO_(4)nanocomposites was modified owing to the formation of a heterostructure.The as-prepared NiFe_(2)O_(4)/BiPO_(4)nanocomposite exhibited promising properties to be used as a novel heterostructure for tetracycline(TC)and Rhodamine B(Rh B)removal.The NiFe_(2)O_(4)/BiPO_(4)nanocomposite degrades TC(98%)and Rh B(99%)pollutants upon solar-light irradiation within 100 and 60 min,respectively.Moreover,the trapping experiments confirmed the Z-scheme approach of the prepared nanocomposites.The efficient separation and transfer of photogenerated electron-hole pairs rendered by the heterostructure were confirmed by utilizing electrochemical impedance spectroscopy,photocurrent experiments,and photoluminescence.Mott–Schottky measurements were used determine the positions of the conduction and valence bands of the samples,and the detailed mechanism of photocatalytic degradation of toxic pollutants was projected and discussed.

Hydrothermal synthesis and luminescence properties of Eu^(3+) and Sm^(3+) codoped BiPO_4

Eu3＋/Sm3＋codoped BiPO4 phosphors were synthesized via a facile hydrothermal method with surfactant-free environment. The X-ray diffraction analysis demonstrated that the samples possessed the standard BiPO4 monoclinic structure. Scanning electron microscopy images showed that all samples composed of well-dispersed, micrometer-sized crystals with shuttle-like shape. Energy transfer from Sm3＋to Eu3＋was confirmed by the luminescence spectra and the decay processes of Sm3＋ 4G5/2→6H5/2 emission. Or-ange-red luminescence could be obtained in Eu3＋/Sm3＋codoped BiPO4 phosphors. The average lifetime of Sm3＋ 4G5/2→6H5/2 emis-sion decreased from 2.70 ms in BiPO4：0.03Sm3＋ to 2.37 ms in BiPO4：0.03Sm3＋,0.05Eu3＋. The strong and wide absorption band around 395 nm, originating from both 7F0→5L6 transition of Eu3＋and 6H5/2→4K11/2 transition of Sm3＋, endowed BiPO4：Eu3＋,Sm3＋phosphors with the potential application in the fields of near UV-excited white-light-emitting diodes.