Crystalline heptazine carbon nitride (HCN) is an ideal photocatalyst for photocatalytic ammonia synthesis. However, the limited response to visible light has hindered its further development. As a noble metal, Au nanoparticles (NPs) can enhance the light absorption capability of photocatalysts by the surface plasmon resonance (SPR) effect. Therefore, a series of Au NPs-loaded crystalline carbon nitride materials (AH) were prepared for photocatalytic nitrogen fixation. The results showed that the AH displayed significantly improved light absorption and decreased recombination rate of photo-generated carriers owing to the introduction of Au NPs. The optimal 2AH (loaded with 2 wt% Au) sample demonstrated the best photocatalytic performance for ammonia production with a yield of 70.3 μmol g− 1 h− 1, which outperformed that of HCN. This can be attributed to the SPR effect of Au NPs and alkali metal of HCN structure. These findings provide a theoretical basis for studying noble metal-enhanced photocatalytic activity for nitrogen fixation and offer new insights into advances in efficient photocatalysts.

Chlorine is a crucial radionuclide that must be removed in irradiated nuclear graphite. Understanding the interaction between chlorine and graphene-based materials is essential for studying the removal process of 36Cl from irradiated nuclear graphite. In this study, first-principle density functional theory (DFT) was utilized to investigate the adsorption characteristic of chlorine on the original and reconstructed edges of graphene-based materials. Based on the calculation of adsorption energy of the structures after each step of adsorption, the most energetically favorable adsorption routes at four types of edge were determined: Along the armchair edge and reconstructed zigzag edge, the following adatoms would be adsorbed to compensate the distortion induced by the previously adsorbed atom. Meanwhile at the original zigzag edge, chlorine atoms would be adsorbed alternatively along the edge to minimize the repulsion between two adjacent chlorine atoms. The chemical nature of the bonds formed as a result of adsorption was elucidated through an examination of the density of states (DOS) for the two adsorbed chlorine atoms and the carbon atoms attached. Furthermore, to assess the relative stability of the adsorption structures, formation energy of all energetically favorable structures following adsorption was computed. Consequently, the predominant adsorption structure was identified as the reconstructed armchair edge with two chlorine atoms adsorbed. The desorption process of 36Cl2 from the predominant structure following adsorption was simulated, revealing an energy barrier of 1.14 V for desorption. Comparison with experimental results suggests that the chlorine removed from reconstructed armchair edges significantly contributes to the low-temperature removal stage of 36Cl from irradiated nuclear graphite.

This study investigated in vitro antioxidant, anti-inflammatory and cytotoxicity on human lung epithelial A549 cells of different solvent extracts from Jerusalem artichoke (Helianthus tuberosus L.) tuber. The EtOH extract contained amounts of phenolics (22.20 tannic acid equivalent ㎎/ɡ) and exhibited the highest antioxidant activity and anti-inflammatory activity. Several methods were employed for measure the antioxidant activity: 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (IC50 = 206.79 ㎍/㎖), reducing power activity (21.26 ascorbic acid equivalent ㎎/ɡ) and total antioxidant activity (19.05 ascorbic acid equivalent ㎎/ɡ). Meantime, the EtOH extract inhibited the NO production completely with a concentration of 800 ㎍/㎖. Besides, the H2O extract exhibited more potent effect on human lung epithelial A549 cells. This study suggested that Jerusalem artichoke tuber had antioxidant, anti-inflammatory and cytotoxicity on human lung epithelial A549 cells.