Degradation Of RhB Research Articles

A novel composite (BiVO4/TiS2) presenting an excellent Z-scheme photocatalytic degradation for Rhodamine B dye under the visible light irradiation

Dye pollutant in the water is the most challenging problem in the textile industries. Novel composites photo-catalysts (BiVO4/TiS2@3%, BiVO4/TiS2@6%, and BiVO4/TiS2@9%) have been prepared to solve this problem. These composites proved promising materials as they have high photocatalytic performance and excellent electro-conductivity properties. Novel BiVO4/TiS2@3%, BiVO4/TiS2@6%, and BiVO4/TiS2@9% composites nanomaterials characterized by Photoluminescence Spectroscopy, UV–visible Diffuse Reflectance Spectroscopy (DRS), Raman Spectroscopy, Energy dispersive X-ray Spectroscopy, Scanning Electron Microscopy, Transmission Electron Microscopy, Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Diffraction Techniques. BiVO4/TiS2@6% shows superior photocatalytic activity and removed RhB molecules (97%) in a very short time of 70 min when irradiated underneath visible light. Compared to pure BiVO4 and TiS2, the average photocatalytic efficiency of composite materials (BiVO4/TiS2@3%, BiVO4/TiS2@6%, and BiVO4/TiS2@9%) was high. Photo generated carrier's transmission becomes smooth due to the very small resistance of BiVO4/TiS2@3%, BiVO4/TiS2@6%, and BiVO4/TiS2@9%. The photoluminescence spectrum (PL) shows that photo-generated carriers of BiVO4/TiS2@6% have the highest separation efficiency. Focusing on a capturing experiment for the degradation of RhB, a good photocatalytic process was presented. It was unexpected to see how quickly the rate of degradation of a new BiVO4/TiS2@6% composite photocatalytic material could still be up to 90% after six cycles. Finally, proposed an excellent photo-catalyst BiVO4/TiS2@6% for wastewater treatment on an industrial scale.

MoSe2 in flower spheres provides abundant active sites for TiO2 photocatalytic degradation of RhB

In this paper, a MoSe2/TiO2 composite photocatalyst was constructed by modifying TiO2 with MoSe2 as a group catalyst. The results showed that pure TiO2 and MoSe2 had no degradation activity for RhB, and the composite catalyst of 0.03 g MoSe2 had the best photocatalytic degradation activity for RhB. Through SEM, TEM, UV-VIS absorption spectrum, transient photocurrent curve, photoluminescence spectrum, and electrochemical impedance spectrum analysis, it can be seen that the excellent performance of 0.03 g MoSe2 composite sample is due to its excellent nanostructure, and uniform TiO2 nanosheets are attached to MoSe2 flower spheres. The active site of RhB photocatalytic degradation was increased, the visible light response and photobiological carrier separation were enhanced, and TiO2 had photocatalytic activity under simulated sunlight.

Effective development and utilization of SILAR-assisted TiO2 and CsPb2Br5 nanocomposites for photochemical and biological cleaning of environment

Recently, cesium lead halide perovskites such as CsPb2Br5 and CsPbBr3 have drawn the attention of researchers because of their unique optical, electronic, and chemical properties. To improve the photo and/or chemical performance of such CsPb2Br5 (termed as CPB hereafter), we have realized multiple facile routes for its combination with UV-active TiO2 nanoparticles. Resultantly developed binary nanocomposites of TiO2, CPB perovskites and TiO2/CPB-nanocomposite (TiO2/CPB-NC) offered a meaningful photochemical contrast between pseudo-successive ionic layer adsorption and reaction (p-SILAR) and electrostatic self-assembly methods for targeting photocatalytic degradation of toxic dyes under solar irradiation and resulted significant performance as reactant for oxygen evolution (OER) as revealed by extensive electrochemical impedance spectroscopy (EIS). In parallel to extensive material-based characterization using SEM, XRD, and UV Vis. etc, the study was further extended to the theoretical investigation of the structure of CsPb2Br5, and antibacterial activity against gram-positive and gram-negative bacteria namely Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). RhB degradation of TiO2 increased from 13% to 58% by deposition of CPB, in parallel to 100% inhition zone growth.

Boosting Visible-Light Photocatalytic Activity of BiOCl Nanosheets via Synergetic Effect of Oxygen Vacancy Engineering and Graphene Quantum Dots-Sensitization.

In recent years, oxygen vacancy (VO) engineering has become a research hotspot in the field of photocatalysis. Herein, an efficient GQDs/BiOCl-VO heterojunction photocatalyst was fabricated by loading graphene quantum dots (GQDs) onto BiOCl nanosheets containing oxygen vacancies. ESR and XPS characterizations confirmed the formation of oxygen vacancy. Combining experimental analysis and DFT calculations, it was found that oxygen vacancy promoted the chemical adsorption of O2, while GQDs accelerated electron transfer. Benefiting from the synergistic effect of oxygen vacancy, GQDs, and dye sensitization, the as-prepared GQDs/BiOCl-VO sample exhibited improved efficiency for RhB degradation under visible-light irradiation. A 2 wt% GQDs/BiOCl-VO composite effectively degraded 98% of RhB within 20 min. The main active species were proven to be hole (h+) and superoxide radical (·O2-) via ESR analysis and radical trapping experiments. This study provided new insights into the effective removal of organic pollutants from water by combining defect engineering and quantum dot doping techniques in heterojunction catalysts.

Construction of carbon-doped mesoporous g-C3N4 catalytic nanoreactor via bubble template method for visible-light photocatalysis

Morphological control of photocatalysts is an important way to improve photocatalytic activity. Herein, we design a carbon-doped mesoporous g-C3N4 nanoreactor by combining the self-assembly method of supramolecular precursors with the bubble template method. The mesoporous structure can increase the utilization rate of light absorption. Furthermore, the C atoms replace the position of bridging N atoms may generate delocalized large π bonds, both of which can facilitate photocatalysis. This nanoreactor coupled with larger specific surface area and faster electronic transmission efficiency shows an outstanding performance in photocatalytic RhB degradation (97%, 15 min) and reducing CO2 into CO (60.82 μmol/g, 5h). The C-doped mesoporous g-C3N4 nanoreactor would provide some practical reference for environmental improvements and clean energy production.

Band engineering of single-halogen layered Sillén oxyhalide, BaBiO2X (X = Cl, Br, and I): The role of lone-pair effect in photocatalysts

Band structure engineering is an effective way to improve the performance of photocatalysis. Herein, layered oxyhalides, BaBiO2X (X = Cl, Br, and I), with single halogen layers were synthesized by using molten salt synthesis method. Density functional theory (DFT) calculation reveals that the valance band maximum (VBM) of BaBiO2X mainly consists of O 2p orbitals, not halogen p orbitals (Cl-3p, Br-4p, and I-5p), which means that this X1 oxyhalide owns the stability against self-degradation by photogenerated holes during the photocatalytic process. Simultaneously, with the increasing of atomic number from BaBiO2Cl to BaBiO2I, the band gap (Eg) decreases from 3.523 eV to 2.777 eV. Eventually, BaBiO2I exhibits the highest photocatalytic RhB degradation performance among all samples, mostly owning to the enhanced light absorption and improved separation and migration efficiency of photogenerated carriers. This study provides a new idea for designing bismuth-based photocatalysts by band engineering to solve environmental pollution.

G-C3N4/In2O3 heterojunction films and their excellent photocatalytic performance in fruit preservation and organic dye degradation

We prepared g-C3N4/In2O3 composite films on the wire mesh of stainless steel by a hydrothermal method combined with annealing. XRD, SEM, and XPS results confirmed the heterojunction formation of g-C3N4/In2O3. UV–vis spectroscopy showed that the heterojunction films exhibited enhanced visible light absorption capacity compared with the pristine In2O3 films. Compared with the individual In2O3 films, the PL intensity of the g-C3N4/In2O3 composite films was remarkably reduced, their photocurrent density was significantly increased, and the semicircle in EIS plots was reduced. All the above changes are attributed to the heterojunction formation between g-C3N4 and In2O3. According to our proposed mechanism, photogenerated electrons transfer from g-C3N4 to In2O3 while the holes move in the opposite direction. Therefore, the spatial transfer and separation of photoinduced electrons and holes was achieved. In other words, the recombination efficiency of photogenerated electrons and holes was remarkably suppressed. In photocatalytic RhB degradation, g-C3N4/In2O3 heterojunction films exhibited much higher photocatalytic activity than the pristine In2O3 films. In our self-made photocatalytic fruit-preservation system, these g-C3N4/In2O3 heterojunction films showed excellent fruit preservation ability. Specifically, the bananas remained turquoise green without turning yellow or black spots, even black patches, after a seven-day evaluation period.

Effect of pH on the photo-Fenton degradation of rhodamine B by Prussian blue/g-C<sub>3</sub>N<sub>4</sub>

The pH solution is one of the critical factors affecting the photo-Fenton degradation of dyes in wastewater. The photoactivity of Prussian blue/g-C3N4 was investigated using the photodegradation of RhB acidic, neutral, and essential medium. The results implicated that more than 98.5% removal of RhB was achieved at pH = 3.62 after irradiation for 60 minutes under visible light. The photocatalytic activity of Prussian blue/g-C3N4 showed the best performance in an acidic medium. This is due to the formation of hydroxyl radicals during the photocatalytic degradation of RhB. Thus, this study has shown the role and potential of the application of photocatalysts in the degradation of toxic organic compounds the wastewater.

Study structure characteristics and the photocatalytic degradation of Rhodamine B on C/g-C<sub>3</sub>N<sub>4</sub> composites

C/g-C3N4 composites were successfully synthesized by calcination method from precursors g-C3N4 (CN) with carbon from orange peel (OC). The products were characterized by physicochemical methods such as XRD, IR, SEM, BET, UV-Vis. The photocatalytic activity of the material was evaluated through the degradation of RhB in the visible light. Experimental results show that the OC/CN-150 composite exhibits the optimal catalytic activity of 90% after 1 hour of illumination. This study highlights the role of carbon synthesized from biomass sources. Besides, it can be combined with other materials to create composites to apply for photocatalysis to solve environmental problems.

Green fabrication of CuO-egTiO2 composite for photodegradation of organic pollutant under direct visible light illumination

A (CuO-egTiO2) composite coated with copper oxide has been manufactured as a green and facile photocatalyst via Argyreia nervosa leaf extract. The photocatalyst consists of equaixial geometry (egTiO2) particles with copper oxide (CuO) nanocrystals deposited on the TiO2 surface in varying proportions. The structural, morphological, and optical properties of the CuO-egTiO2 photocatalyst nanostructures were inspected via various techniques, through (XRD), (FE-SEM), (DRS), (BET) analysis, (PL) spectra, and (TEM). The results obtained revealed the non-uniform growth of CuO nanocrystals on the surface of TiO2 particles, resembling a (core–shell) structure. The photocatalytic activity of the CuO-egTiO2 nanocomposite was verified in the degradation of Rhodamine B dye (RhB) using an inhomogeneous photocatalytic activation process, with CuO-egTiO2 (10 %) proving to be the most effective photocatalyst under visible light. The effect of the catalyst quantity within concentrations of 0.3–1.8 g/L was studied by exposing aqueous solutions containing the photocatalysts to visible radiation. The dye removal rate was estimated by calculating the remaining concentration, indicating a pseudo-first-order disappearance model with a dye removal percentage of 95.20 %. Additionally, the impact of reactive oxygen species (ROS) types was investigated, The highest photocatalytic degradation rate of 52.16 % was observed when using the inhibitor (EDTA), indicating that the active group contributing to the photocatalytic degradation of RhB is hydroxyl radicals (●OH). At last, in reuse experiments, it was demonstrated that the CuO-egTiO2 (10 %) photocatalyst maintained a remarkable 75.3 % of its initial efficiency even after being recycled for four cycles.

Flexible construction of heteroatom-free g-C3N4/g-C3N4 homojunction with switching charge dynamics toward efficient photo-piezocatalytic performance

Photo-piezocatalysis based on homojunction emerges as an auspicious approach for the environmental crisis, while it is still in early stage with limited strategies and ambiguous reaction mechanisms. Herein, a heteroatom-free homojunction of ultrathin g-C3N4 with N vacancies/pristine g-C3N4 has been innovatively constructed through surface coupling effect. It achieves higher performance on both photo-piezocatalytic RhB degradation and H2O2 production than solely piezocatalysis or photocatalysis. The underlying causes lie in the synergistic effects of the internal electric field constructed in the type II homojunction and the polarized electric field stimulated by the non-centrosymmetric structure, which cooperatively facilitate the driving force of the charge carriers. Notably, due to the unfixed polarization direction, the charge transfer pathways undergo transitions between type-II and Z-scheme mechanisms, which both promote the spatial separation and migration dynamics of electrons and holes. This work provides new insights into structural design and mechanism exploration for highly efficient photo-piezocatalytic applications.

Construction of Z-type Bi12O15Cl6/Ag2CO3 photocatalyst for enhanced photocatalytic degradation of RhB and TC

Construction of Z-type Bi12O15Cl6/Ag2CO3 photocatalyst for enhanced photocatalytic degradation of RhB and TC

Amorphous LaWOx nanoparticles with rich O defects for photocatalytic RhB degradation

Water containing organic pollutants is posing an increasingly serious challenge to the clean water resources on which human beings depend. As a promising environmental purification technology, photocatalytic degradation can directly use solar energy to purify polluted wastewater without any secondary pollution. Synthesized via the wet chemical method, LaWOx nanoparticles display ultraviolet light responsiveness, large surface area, amorphous features, and abundant surface oxygen defects. These characteristics empower LaWOx NPs to efficiently degrade Rhodamine B, achieving a 92.76 % degradation efficiency in 105 min and a rate constant (Kap) of 0.02215 min−1 under full-spectrum irradiation. This study offers insights into developing new amorphous nano-photocatalysts.

The flower-like Ni-MOF modified BiOBr nanosheets with enhancing photocatalytic degradation performance

A novel BiOBr/Ni-MOF composite was fabricated by in-situ growth of BiOBr nanosheets on Ni-MOF through a convenient precipitation process. The optimal photocatalytic performance was achieved with a Ni-MOF mass content of 45 wt% in the BiOBr/Ni-MOF composite. This composite exhibited remarkable efficiency, degrading 98.33 % of Rhodamine B in 90 min, surpassing the degradation rate constants of pristine BiOBr and Ni-MOF by 4.2 and 160 times, respectively. The superior performance was primarily ascribed to the efficient separation of photogenerated carriers facilitated by the formation of heterojunctions. Additionally, the increased specific surface area and pore structure provided numerous adsorption and active sites. Radical scavenger experiments and electron spin resonance experiments further revealed that O2− and h+ played crucial roles in the degradation process. Furthermore, the structural properties of the prepared photocatalysts and the effects of different photocatalytic conditions on the degradation of RhB were investigated. This work offers an alternative perspective on the design and fabrication of BiOBr-based composite photocatalysts.

Preparation of La-doped Ti/SnO2-Sb2O4 anode and its electrochemical oxidation performance of rhodamine B.

In this paper, La-doped Ti/SnO2-Sb2O4 electrode was prepared by electrodeposition and used for electrochemical degradation of rhodamine B. The optimum preparation conditions of the electrode were optimized as deposition time of 15min and calcination at 500 ℃ for 2h. The water treatment conditions were selected as initial pH 3.0, electrolyte Na2SO4 concentration 0.1M, current density 30mAcm-2, and initial rhodamine B concentration 20mg L-1; the color and TOC removal of RhB reached 99.78% and 82.41% within 30min. The FESEM, XRD, XPS, CV, LSV, and EIS characterization studies demonstrated that Ti/SnO2-Sb2O4-1%La electrode had a dense structure and the highest oxygen evolution potential (2.14V) and lowest charge transfer resistance (0.198 Ω cm-2), indicating that doped La has lower energy consumption. Moreover, La doping can expand the specific surface area, active site, performance of pollutant degradation, and service life of the electrode. Especially, the service life of Ti/SnO2-Sb2O4-1%La is increased by three times, and the maximum life span reaches 90min (1000mAcm-2, 1M H2SO4). Free radical quenching experiments show that ·OH plays a major role in the degradation of RhB. The Ti/SnO2-Sb2O4-1%La electrode prepared in this paper and its results will provide data support and reference for the design of efficient electrocatalytic electrode.

Silver zirconate: A versatile visible light harvesting photocatalyst for oxygen evolution, PMS activation, and bactericidal activity

Herein, we have synthesized silver zirconate using a co-precipitation method at room temperature. The synthesized Ag2ZrO3 (SZ) was then subjected to calcination at different temperatures (300 °C, 500 °C, and 700 °C). The synthesized Ag2ZrO3 materials were evaluated for their photocatalytic oxygen evolution, activation of peroxymonosulfate (PMS) ions, and antibacterial activity under visible light irradiation. Among the different samples, the SZ sample (Ag2ZrO3 synthesized at room temperature) exhibited the highest photocatalytic oxygen evolution rate (2175.02 μmolg-1h−1). This enhanced performance can be attributed to the higher surface area of SZ compared to the other samples. Furthermore, all four samples were tested for the photoactivation of peroxymonosulfate (PMS) ions to assess their ability for the decontamination of organic pollutant. The SZ photocatalyst demonstrated complete degradation (100 %) of RhB dye (2.1 × 10-5 M) within 120 min of visible light irradiation in the presence of PMS. In contrast, without PMS, only 54.33 % degradation of RhB was recorded in 300 min. This result indicates that SZ effectively activates PMS ions for the degradation of organic pollutants. Additionally, SZ exhibited excellent bactericidal activity against E. coli and S. aureus bacteria, both in the dark and in the presence of visible light. The findings demonstrate the multifunctional properties of Ag2ZrO3, making it suitable for a wide range of environmental remediation applications.

Synthesis of Efficient S-Scheme Heterostructures Composed of BiPO4 and KNbO3 for Photocatalytic N2 Fixation and Water Purification.

The preparation of catalysts with heterojunction structures is a strategy to achieve efficient charge separation and high photocatalytic activity of photocatalysts. In this work, BiPO4/KNbO3 heterostructure photocatalysts were fabricated by a combination of hydrothermal and precipitation methods and subsequently employed in catalyzing N2-to-NH3 conversion and RhB degradation under light illumination. Morphological analysis revealed the effective dispersion of BiPO4 on KNbO3 nanocubes. Band structure analysis suggests that KNbO3 and BiPO4 exhibit suitable band potentials to form an S-scheme heterojunction. Under the joint action of the built-in electric field at the interface, energy band bending, and Coulomb attraction force, photogenerated electrons and holes with low redox performance are consumed, while those with high redox performance are effectively spatially separated. Consequently, the BiPO4/KNbO3 shows enhanced photocatalytic activity. The NH3 production rate of the optimal sample is 2.6 and 5.8 times higher than that of KNbO3 and BiPO4, respectively. The enhanced photoactivity of BiPO4/KNbO3 is also observed in the photocatalytic degradation of RhB. This study offers valuable insights for the design and preparation of S-scheme heterojunction photocatalysts.

Ag/α-Fe2O3/g-C3N4 nanocomposites as Z-scheme heterojunction photocatalysts for degradation of RhB

In this study, Ag/α-Fe2O3/g-C3N4 composites with varying α-Fe2O3 and Ag contents were synthesized by loading α-Fe2O3 and Ag nanoparticles onto the g-C3N4 with a high specific surface area via acid annealing. These composites were then utilized for the photocatalytic degradation of RhB under the irradiation of visible light. For α-Fe2O3/g-C3N4 composites with 5 wt% content of α-Fe2O3, the degradation efficiency reached a peak of 97.57% within 55 min, which was much higher than that of α-Fe2O3 and acid-annealed g-C3N4 with 45.92% and 83.61%, respectively. Furthermore, the photocatalytic degradation efficiency of Ag/α-Fe2O3/g-C3N4 composites reached its maximum of 99.61% with 1% content of Ag. It was demonstrated that the ternary Z-scheme heterojunction construction leaded to a significant enhancement of carrier separation and transfer effects, while the incorporation of Ag serves as electron reservoirs and photoinduced electrons capturers, thereby significantly enhancing the Fenton reaction and photocatalytic performance. This work is significant to drive the widespread application of g-C3N4 based heterojunctions in photocatalytic water purification.

Enhanced photocatalytic degradation of organic dyes by carbon quantum dots-ZnFe2O4 composites

To safely cope with the hazardous methylene blue (MB) and rhodamine (RhB) dyes in wastewater, ZnFe2O4 has shown promise as attractive photocatalytic degradation material. Therefore, we synthesized CQDs-decorated ZnFe2O4 microspheres and successfully degraded MB and RhB dyes under UV light. The CQDs/ZnFe2O4 composites exhibited superior performance as compared to pure ZnFe2O4, achieving nearly 100% degradation of MB in 60 min and 95% degradation of RhB in 80 min. Additionally, the CQDs/ZnFe2O4 material was found stable after four consecutive cycles during the photocatalytic activity. Density functional theory calculations revealed that CQDs generated new gap states near the Fermi level, enhancing the charge separation and conductivity of the composites. The photocatalytic mechanism involved the generation of holes, .OH and .O2 radicals as the active species. These results demonstrate that CQDs/ZnFe2O4 composites can be promising candidates in wastewater treatment along with other wide range of applications.

Redeeming the photocatalytic potential of CuWO4 incorporating Ag6Si2O7 via S-scheme PN heterostructure

Water pollution and energy crisis are deemed the most prevalent issues of contemporary decades, and enhanced efforts to counteract these issues via semiconductor photocatalyst engineering are among the best-proposed solutions. Semiconductor photocatalysts could effectively transform clean sunlight into chemical energy, thereby facilitating the breakdown of organic dyes. Herein, we demonstrate the PN heterojunction S scheme photocatalyst Ag6Si2O7/CuWO4 via the facile hydrothermal method. The Ag6Si2O7/CuWO4 heterostructure discerns the broadening of the absorption spectrum and enhanced carrier separation owing to the interfacial process at the interface. Both these aspects work as a stimulus regarding the photocatalytic properties and add versatilities to the effective utilization of carriers. The performance of different ratios of Ag6Si2O7 and CuWO4 in Ag6Si2O7/CuWO4 composite was monitored via photocatalytic degradation of Rhodamine B and Methylene Blue under visible irradiation. About 97.50% degradation efficiency for RhB was reached in 50 minutes at a 1:5 molar ratio (AgCW-E). The degradation constant rate of AgCW-E for RhB and MB was 21.12 and 26.13 times higher than pristine, respectively. Based on trapping experiments and electron spin resonance spectra, it was determined that the photogenerated holes (h+) and •O2- played a crucial role as active species in the photocatalytic degradation of RhB. The synthetic substances additionally demonstrated great promise for recycling. The present study delivers an innovative perspective on developing a more potent Ag6Si2O7/ CuWO4 nano heterojunction photocatalyst that can capture visible light.