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Sustainable nanocomposites with transparent, biodegradable, and enhanced mechanical and barrier properties were prepared by the incorporation of SiO2 into poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBH) films and subsequent solvent casting. The crystallinity of composites could be increased by 67% with appropriate contents of SiO2, which proved that SiO2 were effective nucleating agents for PHBH. And it was worth mentioning that the contributions of SiO2 to the crystallization and thermal stability of composites are proved effectively by Avrami relationship and Horowitz and Metzger method. More importantly, compared with PHBH, it had not only an enhancement about 40% and 60% on the tensile strength and elastic modulus, respectively, but also half the reduction of the moisture and oxygen permeability which were much higher than the values of conventional plastics. The above, in conjunction with the low migration rate measured in food substitutes, illustrated unambiguously that the nanocomposites might be suitable for potential application in food packaging.

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As a promising photocatalyst material, g-C 3 N 4 has great application potential in energy production and environmental improvement. In this work, surface-modified g-C 3 N 4 nanosheets with excellent stability and high photocatalytic activity were successfully synthesized by physical steam activation. The charge transfer rate of carbon nitride was improved due to the synergistic effect of nitrogen defect and oxygen doping caused by steam activation. Meanwhile, the specific surface area and pore volume of the optimized sample reached 124.3 m 2 g −1 and 0.42 cm 3 g −1 , respectively, which increased the exposed reaction sites of reactants, enhancing the photocatalytic activity of g-C 3 N 4 . In addition, this novel g-C 3 N 4 displayed a great H 2 evolution rate of 5889.39 μmol h −1 g −1 with a methylene blue degradation rate up to 6.52 × 10 −3 min −1 , which was 3.7 and 2.1 times of original g-C 3 N 4 , respectively. This study provided a simple and economical method to develop a highly efficient g-C 3 N 4 photocatalyst for solar energy conversion.