Highly radiation sensitive type IA FBGs for future dosimetry applications

We have studied Co60 gamma-irradiation effect on the characteristics of Type IA fiber Bragg gratings. A record Bragg peak shift of 190 pm was observed for a grating written in Fibercore PS-1250/1500 photosensitive fiber at a radiation dose of 116 kGy. Type IA and Type I gratings show different kinetics under radiation and during post-radiation annealing, which can be used for the design of a grating based dosimetry system.

Highly radiation sensitive type IA FBGs for future dosimetry applications

We have studied Co60 gamma-irradiation effect on the characteristics of Type IA fiber Bragg gratings. A record Bragg peak shift of 190 pm was observed for a grating written in Fibercore PS-1250/1500 photosensitive fiber at a radiation dose of 116 kGy. Type IA and Type I gratings show different kinetics under radiation and during post-radiation annealing, which can be used for the design of a grating based dosimetry system.

Synthesis of novel and stable g-C3N4/N-doped SrTiO3 hybrid nanocomposites with improved photocurrent and photocatalytic activity under visible light irradiation

Hybrid nanocomposites based on N-doped SrTiO3 nanoparticles wrapped in g-C3N4 nanosheets were successfully prepared by a facile and reproducible polymeric citrate and thermal exfoliation method. The results clearly indicated that the N-doped SrTiO3 nanoparticles are successfully wrapped in layers of the g-C3N4 nanosheets. The g-C3N4/N-doped SrTiO3 nanocomposites showed absorption edges at longer wavelengths compared with the pure g-C3N4 as well as N-doped SrTiO3. The hybrid nanocomposites exhibit an improved photocurrent response and photocatalytic activity under visible light irradiation. Interestingly, the hybrid nanocomposite possesses high photostability and reusability. Based on experimental results, the possible mechanism for prolonged lifetime of the photoinduced charge carrier was also discussed. The high performance of the g-C3N4/N-doped SrTiO3 photocatalysts is due to the synergic effect at the interface of g-C3N4 and N-doped SrTiO3 hetero/nanojunction including the high separation efficiency of the charge carrier, band energy matching and the suppressed recombination rate. Therefore, the hybrid photocatalyst could be of potential interest for water splitting and environmental remediation under natural sunlight.

Surface plasmon resonance-induced photocatalysis by Au nanoparticles decorated mesoporous g-C3N4 nanosheets under direct sunlight irradiation

In recent years, surface plasmon-induced photocatalytic materials with tunable mesoporous framework have attracted considerable attention in energy conversion and environmental remediation. Herein we report a novel Au nanoparticles decorated mesoporous graphitic carbon nitride (Au/mp-g-C3N4) nanosheets via a template-free and green in situ photo-reduction method. The synthesized Au/mp-g-C3N4 nanosheets exhibit a strong absorption edge in visible and near-IR region owing to the surface plasmon resonance effect of Au nanoparticles. More attractively, Au/mp-g-C3N4 exhibited much higher photocatalytic activity than that of pure mesoporous and bulk g-C3N4 for the degradation of rhodamine B under sunlight irradiation. Furthermore, the photocurrent and photoluminescence studies demonstrated that the deposition of Au nanoparticles on the surface of mesoporous g-C3N4 could effectively inhibit the recombination of photogenerated charge carriers leading to the enhanced photocatalytic activity. More importantly, the synthesized Au/mp-g-C3N4 nanosheets possess high reusability. Hence, Au/mp-g-C3N4 could be promising photoactive material for energy and environmental applications.

Synthesis of a novel and stable g-C3N4–Ag3PO4 hybrid nanocomposite photocatalyst and study of the photocatalytic activity under visible light irradiation

A facile and reproducible template free in situ precipitation method has been developed for the synthesis of Ag3PO4 nanoparticles on the surface of a g-C3N4 photocatalyst at room temperature. The g-C3N4–Ag3PO4 organic–inorganic hybrid nanocomposite photocatalysts were characterized by various techniques. TEM results show the in situ growth of finely distributed Ag3PO4 nanoparticles on the surface of the g-C3N4 sheet. The optimum photocatalytic activity of g-C3N4–Ag3PO4 at 25 wt% of g-C3N4 under visible light is almost 5 and 3.5 times higher than pure g-C3N4 and Ag3PO4 respectively. More attractively, the stability of Ag3PO4 was improved due to the in situ deposition of Ag3PO4 nanoparticles on the surface of the g-C3N4 sheet. The improved performance of the g-C3N4–Ag3PO4 hybrid nanocomposite photocatalysts under visible light irradiation was induced by a synergistic effect, including high charge separation efficiency of the photoinduced electron–hole pair, the smaller particle size, relatively high surface area and the energy band structure. Interestingly, the heterostructured g-C3N4–Ag3PO4 nanocomposite significantly reduces the use of the noble metal silver, thereby effectively reducing the cost of the Ag3PO4 based photocatalyst.

Synthesis of magnetically separable and recyclable g‑C3N4−Fe3O4 hybrid nanocomposites with enhanced photocatalytic performance under visible-light irradiation

Herein we demonstrate a facile, reproducible, and template-free strategy to prepare g-C3N4–Fe3O4 nanocomposites by an in situ growth mechanism. The results indicate that monodisperse Fe3O4 nanoparticles with diameters as small as 8 nm are uniformly deposited on g-C3N4 sheets, and as a result, aggregation of the Fe3O4 nanoparticles is effectively prevented. The as-prepared g-C3N4–Fe3O4 nanocomposites exhibit significantly enhanced photocatalytic activity for the degradation of rhodamine B under visible-light irradiation. Interestingly, the g-C3N4–Fe3O4 nanocomposites showed good recyclability without loss of apparent photocatalytic activity even after six cycles, and more importantly, g-C3N4–Fe3O4 could be recovered magnetically. The high performance of the g-C3N4–Fe3O4 photocatalysts is due to a synergistic effect including the large surface-exposure area, high visible-light-absorption efficiency, and enhanced charge-separation properties. In addition, the superparamagnetic behavior of the as-prepared g-C3N4–Fe3O4 nanocomposites also makes them promising candidates for applications in the fields of lithium storage capacity and bionanotechnology.