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a b s t r a c tIn this investigation, a facile modification of g-C 3 N 4 through co-pyrolysis of melamine and sodium nitrate or potassium nitrate was reported and the as-synthesized samples were characterized by a collection of techniques, such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, nitrogen adsorption-desorption, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and elemental analysis. Based upon the analysis, we speculated that the g-C 3 N 4 framework was partially destroyed to produce cyano-containing fragments, which resulted into the variation of physical and optical properties, further affecting the adsorption and photocatalytic performance of g-C 3 N 4 on the dye methylene blue. Furthermore, we found that nitrate anions rather than sodium or potassium ions had important effect on the structure and photocatalytic performance of g-C 3 N 4 . In addition, the photocatalysis mechanism and reusability test were also investigated and discussed in the study.

a b s t r a c tA series of TiO 2 hybrids composited with exfoliated g-C 3 N 4 nanosheets (CNs) were successfully synthesized through a facile sol-gel method and fully characterized by X-ray diffraction patterns (XRD), Fourier transform-infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and UV-vis diffuse reflectance spectra (UV-vis DRS). The CNs-TiO 2 hybrids were exposed to visible light irradiation and showed much higher catalytic capability toward degrading dye rhodamine B (RhB) comparing with bare TiO 2 and N-TiO 2 . The sample CNs-TiO 2 -0.05 exhibited the largest apparent reaction rate constant among all CNs-TiO 2 hybrids, which was 2.4 times and 7.0 times as high as bare TiO 2 and N-TiO 2 , respectively. The enhanced catalytic efficiency could be mainly attributed to the well-matched band gap structure with heterojunction interface, suitable specific surface area, and favorable optical property. In addition, active species trapping experiments were conducted, revealing that photoinduced holes (h + ) had a severe influence on catalytic outcome, through which a possible catalytic mechanism was finally realized and proposed.

The photolysis of tetrabromobisphenol A (TBBPA) in aqueous solution under simulated solar light irradiation was studied under different conditions to find out mechanisms and pathways that control the transformation of TBBPA during photoreaction. Particular attention was paid to the identification of intermediates and elucidation of the photolysis mechanism of TBBPA by UPLC, LC/MS, FT-ICR-MS, NMR, ESR, and stable isotope techniques ( 13 C and 18 O). The results showed that the photolysis of TBBPA could occur under simulated solar light irradiation in both aerated and deaerated conditions. A magnetic isotope effect (MIE)-hydrolysis transformation was proposed as the predominant pathway for TBBPA photolysis in both cases. 2,6-Dibromophenol and two isopropylphenol derivatives were identified as photooxidation products of TBBPA by singlet oxygen. Reductive debromination products tribromobisphenol A and dibromobisphenol A were also observed. This is the first report of a photolysis pathway involving the formation of hydroxyl-tribromobisphenol A.

A family of monomers, including 2,5-hexandiol, 2,7-octandiol, 2,5-furandicarboxylic acid (FDCA), terephthalic acid (TA), and branched-chain adipic and pimelic acid derivatives, all find a common derivation in the biomass-derived platform molecule 5-(chloromethyl)furfural (CMF). The diol monomers, previously little known to polymer chemistry, have been combined with FDCA and TA derivatives to produce a range of novel polyesters. It is shown that the use of secondary diols leads to polymers with higher glass transition temperatures (T) than those prepared from their primary diol equivalents. Two methods of polymerisation were investigated, the first employing activation of the aromatic diacids via the corresponding diacid chlorides and the second using a transesterification procedure. Longer chain diols were found to be more reactive than the shorter chain alternatives, generally giving rise to higher molecular weight polymers, an effect shown to be most pronounced when using the transesterification route. Finally, novel diesters with high degrees of branching in their hydrocarbon chains are introduced as potential monomers for possible low surface energy materials applications.

Exfoliated g-C 3 N 4 nanosheets (CNs) were composited with bismuth oxychloride (BiOCl) to fabricate a series of hybrids via a facile chemical deposition-precipitation method in this investigation. The as-synthesized BiOCl-CNs hybrids were then fully characterized by a collection of analytical techniques. It was obviously observed that CNs were in intimate contact with hierarchical BiOCl flowerlike units to form heterojunction structures, which facilitates transfer and efficient separation of photoinduced electronhole pairs, thus greatly increasing catalytic activity upon visible light irradiation. Together with other merits such as enlarged specific surface area, favorable optical properties, and suitable energy-band structures, these robust BiOCl-CNs hybrids showed significantly enhanced photocatalytic performance towards Rhodamine B (RhB) dye removal. Under identical conditions, the apparent photocatalytic reaction rate of the best hybrid BiOCl-CNs-3% was about 2.1 and 26.6 times as high as those of BiOCl and CNs alone, respectively. A possible photocatalytic mechanism was also proposed by means of active species trapping measurements, revealing that superoxide radicals (cO 2 À ) played a crucial role during the catalytic process.

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a b s t r a c tIn this study, a rapid reduction of Cr(VI) and degradation of 2,4,6-trichlorophenol (2,4,6-TCP) in a simultaneous manner was reported through the catalysis of g-C 3 N 4 under visible light ( > 420 nm) irradiation. The effects of initial concentration of reactants, dissolved O 2 and pH value were investigated systematically. It indicated that, under the optimized concentration, the Cr(VI) reduction and 2,4,6-TCP oxidation could be accomplished in couple of hours in the presence of g-C 3 N 4 . And also, the O 2 involvement and low pH value were able to significantly improve the removal rate of Cr(VI) and 2,4,6-TCP. In addition, the reaction mechanism was investigated through monitoring the reduced states of Cr(VI) and active oxygen intermediates formed during photoreaction by ESR and XPS, as well as determining the degradation products of 2,4,6-TCP by HPLC-MS. The results supported that the redox reactions of Cr(VI) and 2,4,6-TCP can be performed simultaneously via a synergistic oxidation-reduction mechanism in the presence of g-C 3 N 4 under visible light irradiation.