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Due to the semi-closed structure of the tunnel, serious air pollution in tunnels from vehicle exhaust becomes an issue which needed to be addressed. Among the exhaust, nitric oxide (NO) is typically considered as one of the main pollutants. In this paper, a superhydrophobic photocatalytic coating was fabricated by a spraying method by airbrush with a WO3/TiO2 photocatalysis for NO degradation. The water advanced contact angle (WACA) of the coating reached 166.32°, and the WACA was still above 145° after the 30 times abrasion test. The coating exhibited an excellent ability to remove inorganic and organic pollutants. Also, the NO degradation efficiency of this superhydrophobic coating under ultraviolet and visible light sources and humid environments was tested. When the relative humidity reached 98%, the NO degradation efficiency of the coating remained unchanged under visible light irradiation compared with the relative humidity of 45%. In addition, the coating exhibited prominent stability of NO degradation during the cyclic test. Furthermore, the WT coating showed stability and synergy of self-cleaning and photocatalysis toward NO degradation, which ensured the long-term use of the coating. Finally, a synergistic mechanism for self-cleaning and photocatalysis was proposed. This may provide a new idea and support for the application of photocatalytic technology in the degradation of NO in the tunnel. [ABSTRACT FROM AUTHOR]

Water pollution caused by dye wastewater is a potential threat to human health. Using photocatalysis technology to deal with dye wastewater has the advantages of strong purification and no secondary pollution, so it is greatly significant to look for new visible-light photocatalysts with high photocatalytic ability for dye wastewater degradation. Semiconductor photocatalyst silver phosphate (Ag3PO4) has high quantum efficiency and photocatalytic degradation activity. However, Ag3PO4 is prone to photoelectron corrosion and becomes unstable during photocatalysis, which severely limits its application in this field. In this study, a tubelike g-C3N4/Ag3PO4 heterojunction was constructed by the chemical precipitation method. An Ag3PO4 nanoparticle was loaded onto the surface of the tubelike g-C3N4, forming close contact. The photocatalytic activity of the photocatalyst was evaluated by the degradation of RhB under visible-light irradiation. The tubelike g-C3N4/Ag3PO4-5% heterojunction exhibited optimal photocatalytic performance. In an optimal process, the degradation rate of the RhB is 90% under visible-light irradiation for 40 min. The recycling experiment showed that there was no apparent decrease in the activity of tubelike g-C3N4/Ag3PO4-5% heterojunction after five consecutive runs. A possible Z-type mechanism is proposed to explain the high activity and stability of the heterojunction. [ABSTRACT FROM AUTHOR]

• PP fiber and nano-TiO 2 modification improves the road performances of PMM. • The optimum ratio of PP fiber and nano-TiO 2 in PMM has been determined. • The PMM showed excellent photocatalytic exhaust degradation capacity. • The PMM significantly reduces the energy consumption and greenhouse gas emissions. To purify severe air pollution in traffic-intensive urban areas and tunnels, an innovative type of photocatalytic micro-surfacing mixture (PMM) was designed, which was enhanced by polypropylene (PP) fiber and nano-TiO 2. In this work, the road performance of sixteen PMMs with the different contents of PP and nano-TiO 2 were evaluated by wet-track abrasion test, wheel rutting deformation test and low-temperature splitting test. The vehicle exhaust (VE) gas degradation capacity of sixteen PMMs was characterized under ultraviolet (UV) light and visible light conditions. The life cycle assessment (LCA) methodology was applied to evaluate the environmental impact of PMM. The results showed that the road performances of PMM were improved with the increase of the PP fibers amount. The VE gas degradation capacity was significantly enhanced with the increase of nano-TiO 2 amount. PMM with 0.2 wt% PP fibers and 60 wt% replacement of mineral filler with nano-TiO 2 was a viable alternative to improve photocatalytic degradation of VE in pavement engineering. In addition, the modified micro-surfacing mixture facilitates a significant reduction in energy consumption and greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

[Display omitted] • A self-cleaning synergistic photocatalytic superamphiphobic coating. • The inhibition of NO 2 production during the NO photocatalytic degradation process. • Synergistic effect of self-cleaning and photocatalysis of photocatalytic coating. • A green NO photocatalytic degradation mechanism of photocatalytic coating. Multitudinous deleterious NO 2 will be produced in the process of NO photocatalytic degradation, which may cause serious secondary pollution. In this study, a self-cleaning synergistic photocatalytic coating was constructed by the simple spray method. The coating has excellent superamphiphobicity and NO degradation performance. In addition, the production of NO 2 in the process of NO degradation by photocatalytic superamphiphobic coating was inhibited, which indicated the greener photocatalytic process exhibited by this photocatalytic coating. Also, to clarify the inhibition of the coating on NO 2 , the NO degradation mechanism of the coating and photocatalyst was investigated by in situ IR, trapping test and EPR spectra, and the possible pathway of NO degradation was summarized. Combining the result of DFT calculation and degradation product analysis, the inhibition of NO 2 and"green" degradation mechanism of the self-cleaning synergistic photocatalytic coating was explored and proposed, which may provide some theoretical support for the "green" application of photocatalysis. [ABSTRACT FROM AUTHOR]

[Display omitted] • g-C 3 N 4 nanosheets were prepared via a molten salts method. • Crystalline g-C 3 N 4 nanosheets was composed of triazine ring unit. • The g-C 3 N 4 nanosheets show the excellent photocatalytic activity for the degradation of RhB. The crystalline g-C 3 N 4 nanosheets have been successfully prepared by one-step molten salts method. The microstructures and optical properties of as-prepared samples were characterized by different techniques, such as XRD, EDS, XPS, SEM, TEM, BET, PL and Uv–vis DRS. The results showed that the unit of the crystalline g-C 3 N 4 nanosheets was composed of triazine ring, which was different from heptazine-based g-C 3 N 4. The crystalline g-C 3 N 4 nanosheets were thin and transparent, which were similar to graphene. The crystalline g-C 3 N 4 nanosheets exhibits the excellent photocatalytic activity, which can degrade 98% RhB within 120 min under visible light irradiation. However, the degradation efficiency of bulk g-C 3 N 4 is only 40% within 120 min. The enhanced photocatalytic activity of g-C 3 N 4 nanosheets can be attributed to 2D nanosheet morphology, which inhibits the electron-hole recombination. In addition, the high specific surface area of g-C 3 N 4 nanosheets positively increases the contact area with pollutants, making the degradation reaction more efficiently. A plausible photocatalytic mechanism was proposed for the degradation of RhB under visible light irradiation. [ABSTRACT FROM AUTHOR]

Photocatalytic coating has been widely studied as a promising material to remove air pollutants. However, the effectiveness and long-term effect of photocatalysis in high relative humidity environment is still the main challenge in this field. In this study, a fluorinated WO 3 -TiO 2 nanorods/SiO 2 epoxy photocatalytic superamphiphobic coating (FTSE coating) was prepared using a simple spraying method. The micromorphology and chemical composition of FTSE coating was characterized by SEM, EDS, FT-IR, XPS and TGA techniques. The advanced contact angle and hysteresis angle test show that the FTSE coating had excellent superamphiphobicity. The mechanical abrasions, corrosion resistance and UV aging tests show that the FTSE coating exhibited reasonable durability. Besides, the NO degradation efficiency of hydrophilic and superamphiphobic coatings with contact angles of 20.19°, 87.74°, 162.93° and 164.47° was tested in different humidity environment. The results showed that the superamphiphobic coating exhibited more superior photocatalytic degradation efficiency (84.02%) than the hydrophilic coating (51.38%) at a high relative humidity (RH=98%). Finally, FTSE coating exhibited prominent photocatalytic stability and the synergistic effect of photocatalysis and self-cleaning. After 30 d outdoor weathering test, the NO degradation efficiency decreased by 13.07% and recovered to the original level after flushing. The improvement mechanism of NO degradation performance was proposed based on the characteristics of superamphiphobic surface. [Display omitted] • A WO 3 -TiO 2 nanorods/SiO 2 photocatalytic superamphiphobic coating. • The reasonable robustness and excellent superamphiphobicity. • The prominent degradation performance in high relative humidity environment. • A mechanism of improving the NO degradation efficiency. [ABSTRACT FROM AUTHOR]