Post-illumination activity of Bi_(2)WO_(6) in the dark from the photocatalytic“memory”effect

Photocatalysts with the photocatalytic"memory"effect could resolve the intrinsic activity loss of traditional photocatalysts when the light illumination is turned off.Due to the dual requirements of light absorption and energy storage/release functions,most previously reported photocatalysts with the photocatalytic"memory"effect were composite photocatalysts of two phase components,which may lose their performance due to gradually deteriorated interface conditions during their applications.In this work,a simple solvothermal process was developed to synthesize Bi2WO6 microspheres constructed by aggregated nanoflakes.The pure phase Bi_(2)WO_(6) was found to possess the photocatalytic"memory"effect through the trapping and release of photogenerated electrons by the reversible chemical state change of W component in the(WO_(4))^(2–)layers.When the illumination was switched off,Bi_(2)WO_(6) microspheres continuously produced H_(2)O_(2) in the dark as those trapped photogenerated electrons were gradually released to react with O_(2) through the two-electron O_(2) reduction process,resulting in the continuous disinfection of Escherichia coli bacteria in the dark through the photocatalytic"memory"effect.No deterioration of their cycling H2O2 production performance in the dark was observed,which verified their stable photocatalytic"memory"effect.

In situ synthesis of CNTs/Fe-Ni/TiO_2 nanocomposite by fluidized bed chemical vapor deposition and the synergistic effect in photocatalysis

Carbon nanotube （CNTs）/Fe-Ni/TiO2 nanocomposite photocatalysts have been synthesized by an in situ fluidized bed chemical vapor deposition （FBCVD） method. The composite photocatalysts were characterized by XRD, Raman spectroscopy, BET, FESEM, TEM, UV-vis spectroscopy, and XPS. The results showed that the CNTs were grown in situ on the surface of TiO2. Fe（Ⅲ） in TiO2 showed no chemical changes in the growth of CNTs. Ni（Ⅱ） was partly reduced to metal Ni in the FBCVD process, and the metal Ni acted as a catalyst for the growth of CNTs. The photocatalytic activities of CNTs/Fe-Ni/TiO2 decreased with the rise of the FBCVD reaction temperature. For the sample synthesized at low FBCVD temperature （500 ℃）, more than 90% and nearly 50% of methylene blue were removed under UV irradiation in 180 min and under visible light irradiation in 300 min, respectively. The probable mechanism of synergistic enhancement of photocatalysis on the CNTs/Fe-Ni/TiO2 nanocomposite is proposed.

Synergy effect between tetracycline and Cr(Ⅵ)on combined pollution systems driving biochar-templated Fe_(3)O_(4)@SiO_(2)/TiO_(2)/g-C_(3)N_(4) composites for enhanced removal of pollutants

Biochar-coupled Fe_(3)O_(4)@SiO_(2)/TiO_(2)/g-C_(3)N_(4) composites were successfully constructed through simple sol-gel and calcination methods.The composites efficiently removed high-concentration toxic tetracycline(TC)by means of·OH and·O_(2)^(−),whose removal rate exhibited 91.88%during 3 h,and the degradation rate constant reached up to 0.0068 min^(−1).The excellent performance can be attributed to the high specific surface area,enhanced visible light response,the introduction of magnetic nanoparticles and biochars expediting charge transfer,Z-scheme heterojunction enhancing the spatial separation of photo-generate carriers and,importantly extraordinary adsorption capacity of 147.96 mg g^(−1).Moreover,the composites showed the most excellent efficiency under the calcination temperature of 450℃,and exhibited good stability with tolerance to a wide range of pH and anions.Interestingly,a synergistic photocatalytic effect was discovered in the TC/Cr(Ⅵ)combined pollution systems,resulting in significantly improved removal of Cr(Ⅵ).Besides,the photocatalytic mechanism and degradation path of tetracycline were also elucidated.All these findings suggested the as-synthesized catalyst was an excellent photocatalyst for removal of TC/Cr(Ⅵ)-contaminated water.

Fabrication of a superamphiphobic coating by a simple and flexible method

A facile and flexible method to prepare raspberry-like nanoparticles that can be used as a superamphipho- bic coating is reported. Anatase TiO2 nanoparticles were chosen as the core because of their irregular morphology and photocatalytic performance. Anatase TiO2 nanoparticles were surrounded tightly by tiny functional fluoride-silica nanoparticles via the hydrolysis-condensation reaction of tetraethoxysi- lane and IH, 1H, 2H, 2H-perfluorodecyl triethoxysilane. The obtained Si-F@TiO2 nanoparticles can be sprayed or dipped directly onto various substrates. The coated film exhibited quite good liquid resistance, even when subjected to water jetting and sand abrasion. The photocatalytic effect of the coated anatase TiO2 with respect to formaldehyde was also studied and discussed. This method will provide more opportunities and fast access to practical applications in surface, environmental, and energy engineering.