Facile Construction of 2D/2D ZnIn2S4-Based Bifunctional Photocatalysts for H2 Production and Simultaneous Degradation of Rhodamine B and Tetracycline.

A two-dimensional/two-dimensional (2D/2D) TiO2/ZnIn2S4 photocatalyst was reasonably proposed and constructed by a two-step oil bath-hydrothermal method. TiO2 nanosheets uniformly grown on the surface of ZnIn2S4 nanosheets and a synergetic effect between the TiO2 and ZnIn2S4 could highly contribute to improving the specific surface area and hydrophilicity of ZnIn2S4 as well as accelerating the separation and transfer of photon-generated e--h+ pairs, and thus enhancing the visible-light photocatalytic degradation and H2 evolution performance of ZnIn2S4. Rhodamine B (RhB) and tetracycline (TC) were simultaneously selected as the target pollutants for degradation in the work. The optimum photocatalytic RhB and TC degradation properties of TiO2/ZnIn2S4-10 wt% were almost 3.11- and 8.61-fold higher than that of pure ZnIn2S4, separately, while the highest photocatalytic hydrogen evolution rate was also observed in the presence of TiO2/ZnIn2S4-10wt% and 4.28-fold higher than that of ZnIn2S4. Moreover, the possible photocatalytic mechanisms for enhanced visible-light photocatalytic degradation and H2 evolution were investigated and proposed in detail. Our research results open an easy pathway for developing efficient bifunctional photocatalysts.

Coupling ZnIn2S4 Nanosheets with MoS2 Hollow Nanospheres as Visible-Light-Active Bifunctional Photocatalysts for Enhancing H2 Evolution and RhB Degradation.

In this study, Mo-glycerate was used as a precursor to create MoS2 hollow nanospheres (HNS), which were then used for the first time to modify ZnIn2S4 nanosheets to create MoS2 HNS/ZnIn2S4 photocatalysts. The findings demonstrate that MoS2 HNS/ZnIn2S4 heterojunctions exhibited remarkably boosted photocatalytic properties and excellent reusability for both RhB degradation and H2 evolution without the use of Pt as a co-catalyst. Among the heterojunctions, the RhB degradation and H2 evolution efficiencies of the optimized MoS2 HNS/ZnIn2S4-3 wt % composite were almost 5 and 34 times higher than those of ZnIn2S4, respectively. The excellent performance of MoS2 HNS/ZnIn2S4-3 wt % might be attributed to the expansion of the visible-light response range and the accelerated separation efficiency of photo-induced carriers, according to the findings of the optical property tests. Based on the established band gap position and characterization results, a potential mechanism for appealing photocatalytic activity over MoS2 HNS/ZnIn2S4 heterojunctions was also postulated.

Fabrication and enhanced visible-light photocatalytic H2production of B-doped N-deficient g-C3N4/CdS Hybrids with robust 2D/2D hetero-interface interaction.

2D layered photocatalysts with proper electronic structure have sparked much attention in the field of visible-light photocatalysis for H2production. Herein, by simply calcining the mixture of ultrathin g-C3N4(CNN) and NaBH4, heteroatom B and N defect were simultaneously introduced into g-C3N4. The obtained modified g-C3N4(BDCNN) was further coupled with 2D flower-like CdS nanosheet. The optimal 2D/2D BDCNN/CdS-15% heterojunction behaved ideal photocatalytic activity for H2revolution by water splitting, and the highest H2revolution rate was as high as 1013.8µmol g-1h-1, which was 6.7 times, 2 times, and 5.8 times of the corresponding values of pristine CNN, BDCNN and CdS respectively. It was evidenced that the band structure of 2D/2D BDCNN/CdS-15% was well tuned for better visible-light adsorption and higher separation efficiency of photo-induced carriers for enhancing H2revolution performance. The achievement in this study provided informative principles for exploring g-C3N4based heterojunctions with higher H2-production performance.

In situ fabrication of a novel CdS/ZnIn2S4/g-C3N4 ternary heterojunction with enhanced visible-light photocatalytic performance.

In this study, a novel g-C3N4-based ternary heterojunction was rationally designed and constructed by the in situ growth of ZnIn2S4 nanosheets and CdS nanoparticles onto the g-C3N4 nanosheets using a facile two-step oil-bath method. Through optimizing the proportion of ZnIn2S4 and CdS component, g-C3N4 nanosheets coupled with ZnIn2S4 nanosheets and CdS nanoparticles (denoted as CdS/ZnIn2S4/g-C3N4) exhibited obviously higher photocatalytic properties for RhB removal than the single-component and dual-component systems. Among the as-obtained ternary photocatalysts, it was found that the ternary CdS/ZnIn2S4/g-C3N4-0.2 photocatalyst displayed the optimum photocatalytic property (96%) within a short time (30 min), which was almost 27.42 and 1.17 times higher than that of pure g-C3N4 and binary ZnIn2S4/g-C3N4-0.7 composite. The excellent activity of the ternary CdS/ZnIn2S4/g-C3N4 heterostructure is assigned to the synergetic effects of CdS nanoparticles, ZnIn2S4 nanosheets and g-C3N4 nanosheets, which not only broaden the visible-light absorption range, but also improve the charge mobility and separation rate, thus boosting the visible-light-driven photocatalytic property of g-C3N4.

In situself-assembly fabrication of ultrathin sheet-like CuS modified g-C3N4heterojunction and its enhanced visible-light photocatalytic performance.

Photocatalysts with heterojunction structure have been widely used for organic degradation. In this study, CuS/g-C3N4heterojunction was formed byin situself-assembly via a simply hydrothermal method. A series of characterizations were applied to analyzing the morphology, structure, optical properties and photo-induced electron transfer of the samples. The effect of CuS mass ratio in the CuS/g-C3N4composite on methyl blue (10 mg l-1) degradation under visible-light illumination was discussed. When CuS mass ratio was 60%, CuS/g-C3N4behaved the highest photocatalytic efficiency which is 17 times higher than that of pure g-C3N4, and the optimal heterojunction exhibited promising photocatalytic stability as well. The synthesized CuS/g-C3N4with intimate contact and promising photocatalytic performance provides important implications on analogous researches on g-C3N4-based heterojunctions for photocatalytic applications.

Enhanced H2evolution performance by carbonized SiC/g-C3N4heterojunction under visible-light illumination.

In this study, carbonized silicon carbide/graphitic carbon nitride ((SiC/C)/g-C3N4) composites were fabricated via a facile calcination method. The optimal SiC/C/g-C3N4composite shows an excellent visible-light photocatalytic activity for water splitting, with the highest hydrogen evolution amount being 200.2µmol, which is four times higher than that of pure g-C3N4when triethanolamine and platinum (1.0 wt%) are used as the sacrificial agent and cocatalyst, respectively. With an intimate interface between SiC/C and g-C3N4, the energy band structure of g-C3N4was well engineered for photocatalytic H2production. This study provides a novel method for fabricating g-C3N4-based heterojunctions for application in environmental conservation.

Enhanced Visible-Light Photocatalytic Performance of SAPO-5-Based g-C3N4 Composite for Rhodamine B (RhB) Degradation.

Novel visible-light responded aluminosilicophosphate-5 (SAPO-5)/g-C3N4 composite has been easily constructed by thermal polymerization for the mixture of SAPO-5, NH4Cl, and dicyandiamide. The photocatalytic activity of SAPO-5/g-C3N4 is evaluated by degrading RhB (30 mg/L) under visible light illumination (λ > 420 nm). The effects of SAPO-5 incorporation proportion and initial RhB concentration on the photocatalytic performance have been discussed in detail. The optimized SAPO-5/g-C3N4 composite shows promising degradation efficiency which is 40.6% higher than that of pure g-C3N4. The degradation rate improves from 0.007 min-1 to 0.022 min-1, which is a comparable photocatalytic performance compared with other g-C3N4-based heterojunctions for dye degradation. The migration of photo-induced electrons from g-C3N4 to the Al site of SAPO-5 should promote the photo-induced electron-hole pairs separation rate of g-C3N4 efficiently. Furthermore, the redox reactions for RhB degradation occur on the photo-induced holes in the g-C3N4 and Al sites in SAPO-5, respectively. This achievement not only improves the photocatalytic activity of g-C3N4 efficiently, but also broadens the application of SAPOs in the photocatalytic field.