Synthesis and Optimization of TiO_2/Graphene with Exposed {001} Facets Based on Response Surface Methodology and Evaluation of Enhanced Photocatalytic Activity

Response surface methodology(RSM) was employed to optimize the control parameters of TiO_2/graphene with exposed {001} facets during synthesis, and its enhanced photocatalytic activities were evaluated in the photodegradation of toluene. Experimental results were in good agreement with the predicted results obtained using RSM with a correlation coefficient(R^2) of 0.9345. When 22.06 mg of graphite oxide(GO) and 2.09 mL of hydrofluoric acid(HF) were added and a hydrothermal time of 28 h was used, a maximum efficiency in the degradation of toluene was achieved. X-ray diffraction(XRD), transmission electron microscopy(TEM), and scanning electron microscopy(SEM) were employed to characterize the obtained hybrid photocatalyst. The electron transferred between Ti and C retarded the combination of electron–hole pairs and hastened the transferring of electrons, which enhanced the photocatalytic activity.

Quasi-Spherical Brookite TiO_2 Nanostructures Synthesized Using Solvothermal Method in the Presence of Oxalic Acid

Brookite TiO_2,the latest TiO_2 photocatalyst,promises to be an interesting candidate for photocatalytic applications because of its unique physical and chemical properties. In this study,pure-phase brookite TiO_2 with a quasi-spherical nanostructure was successfully synthesized via a solvothermal method using tetrabutyl titanate(Ti(OC_4H_9)_4,TBOT) as the Ti source in the presence of oxalic acid. NaOH was used to regulate the pH of solution. The structure and morphology of the samples were then analyzed using multiple methods,such as X-ray diff raction(XRD),Raman spectroscopy,scanning electron microscopy(SEM),transmission electron microscopy(TEM),Brunauer–Emmett–Teller(BET) measurements and ultraviolet–visible diff use spectroscopy(UV–Vis). Photocatalytic activities of the as-synthesized brookite TiO_2 were evaluated by degrading aqueous methylene blue solution under UV light irradiation. The effect of thermal treatment temperature on photocatalytic activity of the samples was also investigated. The produced brookite TiO_2 nanopowders calcined at 500 °C for 2 h showed the highest photocatalytic activity,and the corresponding degradation rate of methylene blue(10 mg/L) reached 96.7% after 90 min of illumination. In addition,the formation mechanism of pure-phase brookite TiO_2 was investigated. It was found that the formation of pure-phase brookite TiO_2 in this study was ascribed to the combined action of oxalic acid and sodium hydroxide.

Synthesis and Application of UV-curable Phosphorous-Containing Acrylated Epoxidized Soybean Oil-based Resins

A novel phosphorous-containing acrylated epoxidized soybean oil-based(P-AESO)resin was developed via the ring-opening reaction of epoxidized soybean oil(ESO)with diphenylphosphinic chloride(DPPC),followed by acrylation of the resulting groups.The chemical structure was characterized by Fourier transform infrared spectroscopy(FT-IR),and ^(1)H nuclear magnetic resonance(^(1)H NMR).Subsequently,the viscosity and volumetric shrinkage of the obtained P-AESO resins were studied.Then the oligomer was formulated into UV-curable coatings,and the mechanical,thermal,and coating properties of the resulting UV-cured bioresins were studied by tensile testing,dynamic mechanical thermal analysis(DMA),thermogravimetric analysis(TGA)coupled with FT-IR spectroscopy(TGA-FT-IR),hardness,adhesion,pencil hardness and chemical resistance.Furthermore,the UV-curing behavior of the P-AESO resin was determined by real-time realtime infrared(RT-IR).Meanwhile,compared with coating from acrylated epoxidized soybean oil(AESO),the P-AESO system coatings showed better volumetric shrinkage,excellent adhesion,and enhanced thermal and glass transition temperature(Tg)while maintaining reasonably final C=C conversions and cross-link density.For instance,the obtained P-AESO/trimethylolpropanetriacrylate(TMPTA)20 material possessed a volumetric shrinkage of 4.1%,Tg of 115.6℃,char yield of 9.47%,and final C=C conversions of 81.4%respectively,which exhibited superior values than that of the AESO/TMPTA20 material.The improvement of the P-AESO coating performances could contribute to the architectures that combined the structural features of phosphorous-containing rigid benzene.The developed P-AESO resin is promising for applications in the UV-curable coatings.