Three-Dimensional Hierarchical Seaweed-Derived Carbonaceous Network with Designed g-C3N4 Nanosheets: Preparation and Mechanism Insight for 4-Nitrophenol Photoreduction

Cu-Based Catalysts Supported on H3PO4-Activated Coffee Biochar for Selective Reduction of Nitroaromatics

Selective reduction of nitroaromatics to the corresponding aromatic amines is extremely an attractive chemical process for both fundamental research and potential commercial applications. Herewith, we report that a highly dispersed Cu catalyst supported on H₃PO₄-activated coffee biochar and the resulting Cu/PBCR-600 catalyst show complete conversion of the nitroaromatics and >97.0% selectivity for the corresponding aromatic amines. The TOF of catalyzing the reduction of nitroaromatics (1.55-460.74 min^-1) is approximately 2 to 15 times higher than those of previously reported non-noble and even noble metal catalysts. Additionally, Cu/PBCR-600 also shows high stability in catalytic recycles. Furthermore, it exhibits long-term catalytic stability (660 min) for practical application in a continuous-flow reactor. The characterizations and activity tests reveal that Cu⁰ existing in Cu/PBCR-600 acts as an active site in nitroaromatics reduction. Also, the further characterization by FTIR and UV-vis demonstrates that N, P co-doped coffee biochar could selectively adsorb and activate the nitro group of nitroaromatics.

Recent Advances in g-C3N4-Based Materials and Their Application in Energy and Environmental Sustainability

Graphitic carbon nitride (g-C₃N₄), with facile synthesis, unique structure, high stability, and low cost, has been the hotspot in the field of photocatalysis. However, the photocatalytic performance of g-C₃N₄ is still unsatisfactory due to insufficient capture of visible light, low surface area, poor electronic conductivity, and fast recombination of photogenerated electron-hole pairs. Thus, different modification strategies have been developed to improve its performance. In this review, the properties and preparation methods of g-C₃N₄ are systematically introduced, and various modification approaches, including morphology control, elemental doping, heterojunction construction, and modification with nanomaterials, are discussed. Moreover, photocatalytic applications in energy and environmental sustainability are summarized, such as hydrogen generation, CO₂ reduction, and degradation of contaminants in recent years. Finally, concluding remarks and perspectives on the challenges, and suggestions for exploiting g-C₃N₄-based photocatalysts are presented. This review will deepen the understanding of the state of the art of g-C₃N₄, including the fabrication, modification, and application in energy and environmental sustainability.

Efficient Activation of Peroxymonosulfate by V-Doped Graphitic Carbon Nitride for Organic Contamination Remediation

Advanced oxidation processes (AOPs) based on peroxymonosulfate (PMS) activation have been developed as an ideal pathway for completely eradication of recalcitrant organic pollutants from water environment. Herein, the V-doped graphitic carbon nitride (g-C₃N₄) is rationally fabricated by one-step thermal polymerization method to activate PMS for contamination decontamination. The results demonstrate the V atoms are successfully integrated into the framework of g-C₃N₄, which can effectively improve light absorption intensity and enhance charge separation. The V-doped g-C₃N₄ displays superior catalytic performance for PMS activation. Moreover, the doping content has a great influence on the activation performances. The radical quenching experiments confirm •O₂^-, SO₄^•-, and h⁺ are the significant species in the catalytic reaction. This work would provide a feasible strategy to exploit efficient g-C₃N₄-based material for PMS activation.