Enriched photocatalytic and photoelectrochemical activities of a 2D/0D g-C3N4/CeO2 nanostructure

The Preparation of g-C3N4/ZnIn2S4 Nano-Heterojunctions and Their Enhanced Efficient Photocatalytic Hydrogen Production

Hydrogen production technology has triggered a research boom in order to alleviate the problems of environmental pollution and the pressure on non-renewable energy sources. The key factor of this technology is the use of an efficient photocatalyst. g-C3N4 is a typical semiconductor photocatalytic material that is non-toxic and environmentally friendly and does not cause any serious harm to human beings. Therefore, it can be applied to drug degradation and the photocatalytic production of H2. Combined with ZnIn2S4, this semiconductor photocatalytic material, with a typical lamellar structure, has become one of the most promising catalysts for research due to its suitable bandgap structure and excellent photoelectric properties. In this study, 10% g-C3N4/ZnIn2S4 nano-heterojunction composite photocatalytic materials were successfully prepared by compounding ZnIn2S4 and g-C3N4 semiconductor materials with good visible-light-trapping ability. Under visible light irradiation, the photocatalytic activity of the composites was significantly better than that of pure g-C3N4 and ZnIn2S4. This is attributed to the formation of a heterojunction structure, which effectively inhibited the recombination of photogenerated carriers through the interfacial contact between the two semiconducting materials, and then improved the separation efficiency of the photogenerated electron-hole pairs, thus enhancing the catalytic activity. In this study, pure g-C3N4 and ZnIn2S4 were prepared using calcination and hydrothermal methods, and then, the composites were synthesized using ultrasonic and hydrothermal means. The differences in the structure, morphology, and hydrogen production performance of the materials before and after recombination were analyzed in detail using XRD, SEM, and FTIR characterization, which further verified that the 10% g-C3N4/ZnIn2S4 nano-heterojunction composites possessed excellent photocatalytic activity and stability, providing new possibilities for the optimization and application of photocatalytic hydrogen production technology.

All-solid-state Z-scheme ZnFe-LDH/rGO/g-C3N5 heterojunction for enhanced sonophotocatalytic degradation of ciprofloxacin: Performance and mechanistic insights

The fabrication of all-solid-state Z-scheme sonophotocatalysts is vital for improving the transfer rate of photogenerated electrons to remove antibiotics present in wastewater. Herein, a novel indirect Z-scheme ZnFe-layered double hydroxide (LDH)/reduced graphene oxide (rGO)/graphitic carbon nitride (g-C3N5) heterojunction was synthesized using a simple strategy. The ZnFe-LDH/rGO/g-C3N5 (ZF@rGCN) ternary composites were systematically characterized using different techniques. Results revealed that the 15%ZF@rGCN catalyst achieved a ciprofloxacin (CIP) degradation efficiency of 95% via the synergistic effect of sonocatalysis and photocatalysis. The improved sonophotocatalytic performance of the ZF@rGCN heterojunction was attributed to an increase in the number of active sites, a Z-scheme charge-transfer channel in ZF@rGCN, and an extended visible light response range. The introduction of rGO further enhanced the charge-transfer rate and preserved the reductive and oxidative sites of the ZF@rGCN system, thereby affording additional reactive species to participate in CIP removal. In addition, owing to its unique properties, rGO possibly increased the absorption of incident light and served as an electronic bridge in the as-formed ZF@rGCN catalyst. Finally, the possible CIP degradation pathways and the sonophotocatalytic Z-scheme charge-migration route of ZF@rGCN were proposed. This study presents a new approach for fabricating highly efficient Z-scheme sonophotocatalysts for environmental remediation.