Catalysis is the most efficient and economical method for treating volatile organic pollutants (VOCs). Among the many materials that are used in engineering, platinized carbon nitride (Pt/g-C₃N₄) is an efficient and multifunctional catalyst which has strong light absorption and mass transfer capabilities, which enable it to be used in photocatalysis, thermal catalysis and photothermal synergistic catalysis for the degradation of benzene. In this work, Pt/g-C₃N₄ was prepared by four precursors for the photothermal synergistic catalytic degradation of benzene, which show different activities, and many tests were carried out to explore the possible reasons for the discrepancy. Among them, the Pt/g-C₃N₄ prepared from dicyanamide showed the highest activity and could convert benzene (300 ppm, 20 mL·min⁻¹) completely at 162 °C under solar light and 173 °C under visible light. The reaction temperature was reduced by nearly half compared to the traditional thermal catalytic degradation of benzene at about 300 °C.

Photocatalytic water splitting is one of the promising approaches to solving environmental problems and energy crises. However, the sluggish 4e⁻ transfer kinetics in water oxidation half-reaction restricts the 2e⁻ reduction efficiency in photocatalytic water splitting. Herein, cobalt vanadate-decorated polymeric carbon nitride (named CoVO/PCN) was constructed to mediate the carrier kinetic process in a photocatalytic water oxidation reaction (WOR). The photocatalysts were well-characterized by various physicochemical techniques such as XRD, FT-IR, TEM, and XPS. Under UV and visible light irradiation, the O₂ evolution rate of optimized 3 wt% CoVO/PCN reached 467 and 200 μmol h⁻¹ g⁻¹, which were about 6.5 and 5.9 times higher than that of PCN, respectively. Electrochemical tests and PL results reveal that the recombination of photogenerated carriers on PCN is effectively suppressed and the kinetics of WOR is significantly enhanced after CoVO introduction. This work highlights key features of the tuning carrier kinetics of PCN using charge-conducting materials, which should be the basis for the further development of photocatalytic O₂ reactions.

Semiconductor photocatalysis is a novel highly efficient and low-cost method for removing organic pollutants from wastewater. However, the photoreduction performance of semiconductors on organic pollutants is limited due to the weak absorption of visible light caused by its wide band gap and low carrier utilization rate resulting from severe electron-holes recombination. In the present study, flower-like NH2-UiO-66 (NU66)/ZnO nanocomposites were prepared using a facile method and exhibited high efficiency under visible light driven photocatalysts. The X-ray diffractometer (XRD), scanning electron microscope (SEM), transmitor electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the prepared samples, indicating that NU66/ZnO was successfully synthesized. The photocatalytic activity of the prepared NU66/ZnO nanocomposites was determined by measuring the photodegradation of methylene blue (MB) and malachite green (MG) under visible-light irradiation. The optimal nanocomposite loading of 5% wt NU66 to NU66/ZnO demonstrated the highest photocatalytic activity for the degradation of MB. The photocatalytic activity of a 5% NU66/ZnO composite was approximately 95-fold and 19-fold higher than that of NU66 and ZnO samples, respectively. The enhanced activity of the 5% wt NU66/ZnO nanocomposite was further confirmed through photoelectrochemical analysis. The formation of type II heterojunctions between the counterparts significantly suppressed recombination of the photogenerated charge carriers. Photocatalytic degradation experiments with different quenchers indicated that the effect of superoxide anion radicals (•O₂⁻ ) had a greater effect than the other scavengers. Additionally, the improved photocatalytic mechanism underlying the activity of NU66/ZnO nanocomposites was also explored. These findings establish a basis for development of MOF based heterojunction for photocatalytic organic pollution remediation.