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Heterogeneous photo-Fenton system is widely studied as a very promising water treatment technology. However, there are still some challenges, such as the recovery of solid catalysts, weak photo-Fenton activity at neutral pH and unclear mechanism of photo-assisted Fenton. Here, we demonstrated that hydrothermal synthesized pyrrhotite (SP) was a visible light photo-Fenton catalyst with excellent magnetic recovery performance toward the degradation of organic pollutants at neutral pH. The catalytic degradation performance of SP was 7.5 and 10 times that of natural pyrrhotite (NP) and commercial FeS (com-FeS), respectively. We found that the acid-base buffer function of SP composite was responsible for the photo-Fenton activity at neutral pH. Furthermore, we show that absence of atoms in SP, the formation of vacancies, are responsible for the excellent activity. Overall, this work provide new insight toward the understand of photo assisted Fenton mechanisms at neutral pH.

In this paper, novel popcorn balls-like ZnFe 2 O 4 -ZrO 2 composite microspheres were successfully fabricated by a simple hydrothermal method. The morphology, structure and optical property of the microspheres were characterized. The microspheres were used as the photocatalysts to degrade 2,4-dinitrophenol, and exhibited superior photocatalytic performance. Under simulated solar visible light irradiation, the degradation rate of ZnFe 2 O 4 -ZrO 2 photocatalyst (mass ratio of ZnFe 2 O 4 /ZrO 2 = 2:1) was almost 7.4 and 2.4 times higher than those of pure ZnFe 2 O 4 and ZrO 2 . The enhancement could attribute to stronger light absorption, lower carrier recombination and multi-porous structure of the microspheres. Moreover, the popcorn balls-like photocatalysts can be easily separated, because of the magnetism of the samples. After five times runs, the photocatalyst still showed 90% of its photocatalytic degradation efficiency. This work demonstrated a good prospect for removing organic pollutants in water.

The scrupulous design of hierarchical structure and highly active crystal facets exposure is essential for the creation of photocatalytic system. However, it is still a big challenge for scrupulous design of TiO2 architectures. In this paper, bird’s nest-like anatase TiO2 microstructure with exposed highly active (001) surface has been successfully synthesized by a facile one-step solvothermal method. Methylene blue (MB) is chosen as a model pollutant to evaluate photocatalytic activity of as-obtained TiO2 samples. The results show that the photocatalytic activity of the bird’s nest-like sample is more excellent than P25 in the degradation of MB due to high specific surface area and highly active (001) crystal facets exposure when tested under simulated solar light. Besides, it can be readily separated from the photocatalytic system by sedimentation after photocatalytic reaction, which is a significant advantage against conventional powder photocatalyst. The bird’s nest-like microspheres with novel structure may have potential application in photocatalysis and other fields.

The pharmaceutical products have becoming ubiquitous in aquatic environment. Photocatalytic degradation is considered as a promising strategy to address this environmental threat. Here we showed new Mo2C/hollow tubular g-C3N4 hybrids (Mo2C/TCN) consisting of well-designed direct Z-scheme heterojunction with favorable charge transfer channels for efficient contaminants degradation. Compare to the traditional Mo2C/g-C3N4 type-I heterojunction reported in the previous literature, the powerful direct Z-scheme heterojunction retains the original redox ability of the component without changing its oxidation and reduction potential. By virtue of the hollow tubular architecture, more incident electrons are expected to be rapid trapped by Mo2C nanoparticles, which contributes to the effective separation of photoinduced hole-electron pairs. As a result, the optimized Z-scheme system exhibits impressive visible-light photocatalytic performance. Especially, the 2 wt% Mo2C/TCN photocatalysts exhibits superior photocatalytic performance for tetracycline degradation with a reaction rate of 0.0391 min−1, which is 3-times and 9-times higher than those of TCN and pristine g-C3N4, respectively. The outstanding performance strongly depends on the synergistic effects among the favorable electrical conductivity of Mo2C and the multitude of charge transfer channels provided by the Z-scheme heterojunction. This work provides a new idea of designing direct Z-scheme material and it sheds novel insight to establish photocatalytic model for environmental amendment.

Generally, pristine semiconductor materials are difficult to own excellent photocatalytic performance, and doping is considered an effective strategy to improve their performance. Herein, Co-doped BiOBr (0 1 0) was successfully synthesized. The improved performance could be attributed to the enhanced charge separation efficiency and the expanded light absorption region. Moreover, Co-doped BiOBr (0 1 0) owned relatively rough crystal surface with rich atomic defects and large specific surface area, which leaded to its excellent adsorption performance that contributed to the hole-dominated degradation process. Through density functional theoretical (DFT) calculation, the effect of Co doping on electronic structure of BiOBr was investigated, indicating that an additional energy level inserted into the band gap of Co-doped BiOBr, the band structure of Co-doped BiOBr was more intensive than that of BiOBr, and the CBM and VBM of the Co-doped BiOBr shifted towards lower energy regions. Tetracycline hydrochloride was chosen to further evaluate the photocatalytic performance of as-prepared Co-doped BiOBr (0 1 0), and 83% of tetracycline hydrochloride was degrade within 30 min. Finally, the visible-light driven catalytic mechanism of Co-doped BiOBr (0 1 0) was elucidated. Thus, a feasible strategy was proposed for the fabrication of excellent visible-light-driven photocatalytic materials.