Search

The protection of water resources has attracted enormous consideration aswater pollution is now the bottleneck of sustainable development of popular society. For this purpose, eco-friendly efficient photo-catalysts are urgently required. This work focuses on the synthesis and characterization of nitrogen-doped porous carbon/ZnO nanorod arrays (PC/ZnO NRs) as a photo-degradation catalyst. Using absorbent cotton as a carbon source, nitrogen doped porous carbon was obtained by urea decomposition during the carbonization process of cotton at set temperatures. ZnO NRs were grown on the porous carbon to form the PC/ZnO NR hybrid. The prepared samples were systematically characterized, and their photo-catalysis capability was evaluated by the degradation process of rhodamine B (RhB). It is found that PC500/ZnO NRs demonstrated an efficient photo-catalysis under Xe lamp irradiation, such that over 96.5% of RhB (10 ppm) could be photo-degraded within 20 min with 10 mg. The mechanism is discussed based on the tight interfacial bonding and the appropriate Fermi energy between porous carbon and ZnO NRs, which enhanced the separation efficiency of photo-generated charge carriers and provided an ultrahigh density of catalytic reaction centers. Overall, this green and scalable fabrication technology will provide new insights into a reasonable design for high performance photo-catalysts and environmental pollutant management. [ABSTRACT FROM AUTHOR]

The present study focuses on the synthesis and characterization of a ternary photo-catalyst: rGO–Sb4O5Cl2–Sb2S3. A series of rGO–Sb4O5Cl2–Sb2S3 samples were synthesized by the ultrasonic-assisted chemical co-precipitation method and the photo-catalytic capability was evaluated by the photo-degradation of methyl orange (MO) under visible light irradiation. The photo-catalysis rate of rGO–Sb4O5Cl2–Sb2S3 was higher than those of Sb2S3, 10rGO–Sb2S3, Sb4O5Cl2 and Sb4O5Cl2–Sb2S3. The as-prepared material (30rGO–Sb4O5Cl2–Sb2S3, 5 mg) had the highest photo-degradation effect on MO (50 mL, 20 mg L−1), and 87.4% MO degraded within 16 min. The cycling test has proven that the produced rGO–Sb4O5Cl2–Sb2S3 has anti-photoerosion ability. The morphology, structure and opto-electronic properties have been characterized as well. Thus, the mechanism has been discussed: the extraordinary photo-degradation effect on MO results from the synergetic effect of ultrathin rGO sheets and Sb4O5Cl2 grains. Sb4O5Cl2 was the photo-generated charge carrier migration medium and rGO would enhance the catalytic efficiency because of the ultra-large specific surface area and numerous surface active sites. [ABSTRACT FROM AUTHOR]

The electro-magnetic mechanism and chemical transfer mechanism coexist in the surface-enhanced Raman scattering (SERS) procedure. However, the latter is regretfully neglected due to the poor chemical transfer efficiency without the aid of a direct chemical bond. Herein, to further explore the CM Raman enhancement and understand the mechanism of SERS, Raman testing and the adsorption experiment have been carried out with respect to the exploration and application of metal-free SERS substrate. Thus, functional organic group-modified MoS2 nanosheets have been prepared via the hydrothermal method, and this as-prepared MoS2 shows an apparent Raman signal enhancement effect when serving/as the Raman substrate. Compared with those without organic groups (purchased MoS2) and those with one organic group removed (annealed MoS2), it is found that the minimum detection concentration of Rhodamine B (RhB) with the as-prepared functional MoS2 nanosheets could be 0.1 ppm, while the detection limit of annealed as-prepared MoS2 nanosheets and commercially purchased MoS2 powders were only 1 ppm and 10 ppm, respectively. Fourier transition infrared spectroscopy has revealed that the surface of the as-prepared MoS2 nanosheets was passivated by –NH2 and C=C and C=O groups. The lone pair electrons in –NH2 and the p-bond electrons in C=C and C=O groups would coordinate the nitrogen ethyl of RhB, forming a direct chemical bond, which could significantly contribute to the charge transfer. This led to efficient adsorption of the RhB molecule, which is key to achieving the SERS effect with the prepared MoS2 nanosheets substrate. [ABSTRACT FROM AUTHOR]