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In this work, highly active graphitic carbon nitride composite photocatalysts with an isotype heterojunction semiconductor structure have been prepared through the molecular composite precursors consisting of urea and melamine. These photocatalysts were characterized by XRD, SEM, TEM, UV-Vis, BET and transient photocurrent responses. The photodegradation of dyes in aqueous solution under visible-light irradiation has been investigated over carbon nitride photocatalysts consisting of different urea/melamine mass ratios. Further studies by photocurrent indicate that the photosynergistic effect of isotype heterojunction can remarkably enhance the photoinduced interfacial charge transfer, thereby increasing the charge separation during the photocatalytic reaction.

Replacing the high theoretical potential of anodic water decomposition (oxygen evolution reaction) with the low theoretical potential of urea oxidation reaction (UOR) is an urgent need for hydrogen energy storage and conversion. Cobalt nitride nanoflakes, high-performance bifunctional catalysts supported on nickel foam (Co${}_{5.47}$N NF/NF), were synthesized by hydrothermal and calcination method. The morphology and composition of the catalyst were studied by XRD, XPS, SEM, TEM, HRTEM and elemental analysis. In order to conduct electrochemical performance and stability, a two-electrode electrolyzer composed of Co${}_{5.47}$N NF/NF as both anode and cathode materials is constructed (Co${}_{5.47}$N NF/$\mathrm{\text{NF}}||{\mathrm{\text{Co}}}_{5.47}$N NF/NF). Only a voltage of 1.687V is needed to complete 100$\mathrm{\text{mA}}\cdot {\mathrm{\text{cm}}}^{-2}$. It is much lower than the voltage of Pt/$\mathrm{\text{C}}||{\mathrm{\text{IrO}}}_2$ (1.816V), because of which it is believed that this work provides a valuable route for the design of inexpensive and efficient urea electrolysis-assisted hydrogen generation.

For the treatment of dye wastewater, it is of great significance to develop new adsorbents with high adsorption capacity and good separation effect. In this study, the Fe-Co magnetic activated carbon material (CN-Fe-Co-AC) was first prepared by high-temperature calcination. CN-Fe-Co-AC is physically characterized by various methods. CN-Fe-Co-AC can efficiently and quickly remove the organic dyes methylene blue (MB) and acid blue 80 (AB80). The adsorption of MB and acid blue based on CN-Fe-Co-AC adsorbent is mainly through the specific surface area and the functional groups on the surface. During this recovery process, the adsorption activity of CN-Fe-Co-AC for MB and AB80 decreased slightly. Kinetic data can be described using a Pseudo-second-order model and the data for adsorption equilibrium can be described using the Langmuir isotherm. The theoretical adsorption capacities of MB and AB80 are 104.82mg/g and 26.94mg/g, respectively. After repeated use of five times, the removal rate of MB exceeded 96%, and the removal rate of AB80 exceeded 75%. The excellent adsorption performance and recyclability of CN-Fe-Co-AC indicate that this material has certain potential application value.

We have previously hypothesized that density-dependent natural selection is responsible for a genetic polymorphism in crowded cultures of Drosophila. This genetic polymorphism entails two alternative phenotypes for dealing with crowded Drosophila larval cultures. The first phenotype is associated with rapid development, fast larval feeding rates but reduced absolute viability, especially in the presence of nitrogenous wastes like ammonia. The second phenotype has associated with it the opposite set of traits, slow development, slow feeding rates and higher viability. We suggested that these traits are associated due to genetic correlations and that an important selective agent in crowded larval cultures was high levels of ammonia. To test this hypothesis we have examined viability and larval feeding rates in populations kept at low larval densities but selected directly for (i) rapid egg-to-adult development, (ii) tolerance of ammonia in the larval environment and (iii) tolerance of urea in the larval environment. Consistent with our hypothesis we found that (i) larvae selected for rapid development exhibited increased feeding rates, and decreased viability in food laced with ammonia or urea relative to controls, and (ii) larvae selected to tolerate either ammonia or urea in their larval environment show reduced feeding rates but elevated survival in toxin-laced food relative to controls. It would appear that development time and larval feeding rate are important characters for larvae adapting to crowded cultures. The correlated fitness effects of these characters provide important insights into the nature of density-dependent natural selection.