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In this work, a novel Ag 3 PO 4 @CoFe 2 O 4 composite photocatalyst was synthesized via a phosphate salts alkalinity adjustment strategy. Structure, morphology, and chemical component analysis indicated that the magnetic CoFe 2 O 4 nanoparticles (NPs) were evenly decorated on the surface of Ag 3 PO 4 particles, forming a sesame ball like structure. This unique structure ensures that the Ag 3 PO 4 @CoFe 2 O 4 composites could be totally separated by the magnet field. Photocatalytic water disinfection and organic pollutants degradation were employed to evaluate the photocatalytic performance of the as-prepared magnetic photocatalysts. The results showed that the optimum 3% Ag 3 PO 4 @CoFe 2 O 4 composite could completely inactivate 1*10 7 cfu/mL of Escherichia coli within 40 min, much faster than the pristine Ag 3 PO 4 . Meanwhile, the 3% Ag 3 PO 4 @CoFe 2 O 4 composite also showed a dramatic enhancement of photocatalytic activities for the organic pollutants degradation. The reactive oxygen species yield measurements, O 2 control photocurrents experiments, O 2 -TPD tests and photoluminescence spectra analysis indicate that the surface modification of CoFe 2 O 4 NPs could facilitate the O 2 adsorption and O O bond activation/cleavage/oxide removal and accelerate the two-electron oxygen reduction reaction for H 2 O 2 generation on the surface of Ag 3 PO 4 , and thus more ROSs were generated. In addition, due to the acceleration of electrons consumption, more holes will be left for the organic pollutants oxidation, and the photocatalytic activities as well as stability of Ag 3 PO 4 therefore have been greatly improved. [ABSTRACT FROM AUTHOR]

A magnetic photocatalytic CoFe 2 O 4 /g-C 3 N 4 composite was successfully synthesized by a simple calcination method. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), infrared (IR) spectra, UV–Vis diffuse reflection spectroscopy (DRS) and X-ray photoelectron spectroscopy (XPS) were applied to characterize the as-prepared samples. The magnetic properties of CoFe 2 O 4 and CoFe 2 O 4 /g-C 3 N 4 composites were measured by using a vibrating sample magnetometer (VSM) at room temperature. Photocatalytic property of the CoFe 2 O 4 /g-C 3 N 4 composite was assessed by degrading methylene blue (MB) in aqueous medium under visible light irradiation. The results showed that the composite of 41.4% CoFe 2 O 4 /g-C 3 N 4 exhibited the highest photocatalytic activity. It could activate H 2 O 2 to degrade MB up to 97.3% in 3 h under the visible light irradiation. This enhancement could be attributed to the synergistic effect between CoFe 2 O 4 and g-C 3 N 4 , which could enhance their activity of activating H 2 O 2 to degrade MB under visible light. The CoFe 2 O 4 /g-C 3 N 4 composites also have a strong magnetic ability. After the photocatalytic reaction, it can be quickly separated from the water by an extra magnetic field. Moreover, a possible photocatalytic mechanism was proposed. [ABSTRACT FROM AUTHOR]

Phase engineering plays a critical role in enhancing photocatalytic performance of metal oxides. Herein, we demonstrate the phase-selective synthesis of MoO 3 (hexagonal h-MoO 3 , orthorhombic α-MoO 3 , and their junction h/α-MoO 3) through controlled phase transitions by adjusting annealing conditions. As evidenced with photocatalytic hydrogen evolution reaction, h/α-MoO 3 (14.20 μmol/h) phase junction shows superior performance to either h-MoO 3 (9.62 μmol/h) or α-MoO 3 (11.31 μmol/h), with a hydrogen yield of 47.6% and 25.6% greater than that of h-MoO 3 and α-MoO 3 (Pt as cocatalyst), respectively. A systematic study of the chemical structure characterizations, photochemical tests, band structure analysis, and photocatalytic activity evaluation reveal that, the enhancement is attributed to the strong built-in electric field in the h/α-MoO 3 phase junction, which effectively facilitates charge separation. Our findings introduce a novel strategy for improving photocatalytic performance using phase engineering. [Display omitted] • MoO 3 with different phase structures can be synthesized by controllable phase transition for h-MoO 3 to α-MoO 3. • Heterophase h/α-MoO 3 demonstrates enhanced photocatalytic hydrogen production efficiency h-MoO 3 and α-MoO 3. • Phase junction induced built-in electric field can promote charge separation toward improved photocatalysis. [ABSTRACT FROM AUTHOR]

The ionic liquid added to bulk C 3 N 4 acts as a good electron migration bridge and improves the electron migration efficiency. At the same time, the band gap is widened, the recombination rate after migration is reduced, and the reaction process is accelerated. • Ionic liquid modified g-C 3 N 4 was constructed for degrading environmental hormones. • IL can improve electron mobility and inhibit carrier recombination during synthesis. • Adding ionic liquids to carbon nitride improve the photocatalytic efficiency. For this study, ionic liquid-modified carbon nitride (hm-CN) was one-step synthesized by 1-butyl-3-methylimidazolium cyanamide and carbon nitride (g-C 3 N 4). After the addition of ionic liquids, the structural change of hm-CN increases the separation of photogenerated electron holes and improves the photocatalytic performance. The colorless pollutant bisphenol A (BPA) is degraded as the target pollutant under the visible light irradiation. The catalytic performance of g-C 3 N 4 modified by ionic liquid is better than pure g-C 3 N 4. The best performance is 30hm-CN, which degrades 95% of the pollutants in 3 hours. Its degradation performance is 4.5 times that of pure g-C 3 N 4 and the degradation performance is still excellent after three cycles. According to electron spin resonance (ESR) and trapping experiments, h+ and •O 2 − play a key role in the photocatalytic degradation process. In addition, we conducted a series of condition experiments to perform degradation under different catalyst concentrations, different ions and different pH to fully understand the impact of external interference on the catalyst. At the same time, the sample also has good activity in degrading other pollutants (Rhodamine B, Methylene blue, Tetracycline, Ciprofloxacin). This study simply designed a method to synthesize ionic liquid modified g-C 3 N 4 for improving photocatalytic performance, and provided a new idea for the research of carbon nitride modification at the same time. [ABSTRACT FROM AUTHOR]

Graphical abstract The interlayer of Fe species on a semiconductor can act as a cocatalyst for photogenerated electrons extraction and offering active sites to boost the ROSs yield, as well as speed up the reaction process. Highlight • Constructed a Fe-doped surface alkalinized g-C 3 N 4 composites remove antibiotics. • Fe species can worked as cocatalyst for extracting the photogenerated electrons. • Fe species provide the active site as a cocatalyst. • Fe species improve the photocatalytic degradation efficiency of tetracycline. Abstract A one-step calcination method was designed to synthesize Fe-doped surface-alkalinized graphitic carbon nitride (g-C 3 N 4). Results of transmission electronmicroscope (TEM) and elemental mapping, X-ray photoelectron spectroscopy (XPS) indicated that the Fe species might exist between layers in g-C 3 N 4. From the photoluminescence (PL) and transient photocurrent response results, doping trace amounts of Fe could accelerate the separation of photo-generated carriers, and further increase the generation of active species. Among various photocatalysts, the composite (0.05 wt% Fe) exerts maximum photocatalytic performance in the degradation of tetracycline (TC) under visible-light irradiation. A very low Fe species content of 0.05% resulted in a 3 fold higher reaction rate than that of bulk g-C 3 N 4. In addition, the as-synthesized materials exhibited efficient and stable visible light driven photodegradation activity in degradation of TC, which could be used as a candidate for application eliminating antibiotics in the environment. [ABSTRACT FROM AUTHOR]

ZnFe 2 O 4 /AgI composites were first prepared successfully with a hydrothermal method, and ZnFe 2 O 4 nanoparticles were uniformly decorated on the surface of AgI particles. The photocatalytic activities of the obtained ZnFe 2 O 4 /AgI composites were investigated by the degradation of organic pollutants and the inactivation of bacteria under visible light irradiation. The results showed that the introduction of ZnFe 2 O 4 greatly enhanced the light harvesting ability and improved the separation efficiency of the photogenerated charge carriers, which contributed to the enhanced generation of reactive species and thus promoted the photocatalytic performance. The 5% ZnFe 2 O 4 /AgI composite exhibited the optimal photocatalytic disinfection of E. coli (100% removal efficiency in 80 min) as well as the photocatalytic degradation of rhodamine B (RhB) (98.5% removal rate in 40 min). Furthermore, four consecutive cycles also demonstrated the stable photocatalytic activity of the as-prepared ZnFe 2 O 4 /AgI composites. In addition, H 2 O 2 was identified as the predominant active species in the photocatalytic inactivation of bacteria. This study indicated that ZnFe 2 O 4 /AgI composites are a promising candidate for the treatment of wastewater. [ABSTRACT FROM AUTHOR]