Facile synthesis of Bi2S3 hierarchical nanostructure with enhanced photocatalytic activity

Current trends in textile wastewater treatment-bibliometric review

A bibliometric study using 1992 to 2021 database of the Science Citation Index Expanded was carried out to identify which are the current trends in textile wastewater treatment research. The study aimed to analyze the performance of scholarly scientific communications in terms of yearly publications/citations, total citations, scientific journals, and their categories in the Web of Sciences, top institutions/countries and research trends. The annual publication of scientific articles fluctuated in the first ten years, with a steady decrease for the last twenty years. An analysis of the most common terms used in the authors' keywords, publications' titles, and KeyWords Plus was carried out to predict future trends and current research priorities. Adsorbent nanomaterials would be the future of wastewater treatment for decoloration of the residual dyes in the wastewater. Membranes and electrolysis are important to demineralize textile effluent for reusing wastewater. Modern filtration techniques such as ultrafiltration and nanofiltration are advanced membrane filtration applications.

Metal sulphides and their heterojunctions for photocatalytic degradation of organic dyes-A comprehensive review

Water pollution caused by organic dyes is one of the greatest threats to the ecosystem. The removal of dyes from water has remained a challenge for scientists. Recently, metal sulphides have emerged as a potential candidate for water remediation applications. The efficient charge transportation, greater surface-active sites, and low bandgap of metal sulphides make them an excellent choice of semiconductor photocatalysts for degradation of dyes. This review summarises the potential application of metal sulphides and their heterojunctions for the photocatalytic degradation of organic dyes from wastewater. A detailed study has been presented on the synthesis, basics of photodegradation and heterojunctions and photocatalytic activity. The effect of the use of templates, doping agents, synthesis route, and various other factors affecting the photocatalytic activity of metal sulphides have been summarised in this review. The synthesis techniques, characterisation techniques, mechanism of degradation of organic dyes by Z-scheme heterojunction photocatalyst, reusability and stability of metal sulphides, and the scope of future research are also discussed. This study indicates that Scopus-based core gathered data could be used to give an objective overview of the global dye degradation research from 2008 to 2023 (15 years). All data (articles, authors, keywords, and publications) is compiled in the Scopus database. For the bibliometric study, 1962 papers relevant to dye photodegradation by sulfide-based photocatalysts were found, and this number rises yearly. A bibliometric analysis provides a 15-year evaluation of the state-of-the-art research on the impact of metal sulfide-based photocatalysts on the photodegradation of dyes.

Ultrafast photodegradation of textile industry dyes using efficient sulfide based ternary nanocomposites

We developed novel zinc-cadmium-bismuth sulfide (Zn-Cd-Bi₂S₃) and Zn-Cd-SnS nanocomposites to fabricate a heterojunction by an easy chemical technique to improve photocatalytic degradation of textile dye. Crystalline size and lattice parameter are analyzed using X-ray diffraction (XRD) spectrometer. The obtained strong diffraction peaks with various diffraction planes confirm the fabrication of a high crystal quality nanocomposite as well as the identification of its mixed crystal structure. The morphological information is studied using scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (TEM). Due to its higher surface energy, the as-prepared nanocomposite displayed agglomeration by adjoining to tiny particles. The roughness of surface is studied by atomic force microscopy (AFM). Fourier transform-infrared spectroscopy (FT-IR) used to study about presence of organic functional groups on the surface of nanocomposite. Using UV-Visible and photoluminescence spectra, the impact of shifting the positions of Sn and Bi ions on the optical characteristics is investigated. Thermal property of the nanocomposite is studied by thermogravimetric-differential thermal analysis (TG-DTA) at air atmosphere. We examine and compared the photocatalytic activity of Zn-Cd-Bi₂S₃ and Zn-Cd-SnS nanocomposites for the crystal violet (CV) dye. Under the sun light irradiation Zn-Cd-Bi₂S₃ nanocomposite demonstrated a highest percentage of degradation (88.5%) within a short period (120 min). The obtained photocatalytic results indicate that the active radicals •O_2-, h⁺, and •OH- are favourable for the photocatalytic reaction. A possible photocatalytic mechanism for the dye degradation for the photocatalyst is proposed. Due to the narrow band gap, wide range of incident light captured by the heterostructure nanocomposite and the photogenerated electrons and holes is effectively separated in the Zn-Cd-Bi₂S₃.

Enhanced photodegradation of methylene blue from aqueous solution using Al-doped ZnS nanoparticles

The post-transition semiconducting material of pure zinc sulfide (ZnS) and various concentrations of aluminum (Al) (2.5 wt%, 5.0% wt, 7.5 wt%, and 10% calcined at 200 °C) doped ZnS nanoparticles (NPs) were synthesized by sol-gel procedure. The crystal-like nature and phase structure of the product were examined by powder XRD analysis. This analysis shows that the pure ZnS nanoparticle does not form any secondary phase. The functional group of synthesized materials was analyzed by FTIR examination. The energy gap of the materials is calculated using electro-optic analysis and the Kubelka-Munk equation varies from 3.04 nm to 3.63 nm. The photoluminescence studies show the wide emissions (blue to green) for pure ZnS and Al-doped ZnS nanomaterials. The SEM images show the spherical structure and the agglomerated nanostructures. The presence of Zn, S, and Al are confirmed by EDAX spectra. From HR-TEM studies, pure ZnS and Al-doped ZnS nanoparticles exhibit uniform particle sizes. The rate of degradation was observed using MB dye. MB dye has maximum wavelength (λ_max) of 664 nm. The dye degradation efficiency was improved as the dye ratio increased. Photocatalytic activities studies show the intensity of photocatalytic activities decreased for the maximum time interval. Doping of Al in ZnS boosts the photocatalytic activity. Hence, Al-doped ZnS appears to be better decomposing MB dye when exposed to visible light.

A near-infrared light-driven photoelectrochemical aptasensing platform for adenosine triphosphate detection based on Yb-doped Bi2S3 nanorods

Due to its capability of low spectral interference, high light stability, and minimal photodamage to biological species, near-infrared (NIR) light is advantageous in biosensing and biochemical analysis. This work developed a photoelectrochemical (PEC) aptasensor for adenosine triphosphate (ATP) detection using NIR light as the irradiation source. In order to utilize NIR light, we prepared Yb-doped Bi₂S₃ (Yb-Bi₂S₃) nanorods to act as photoelectric transducing materials. Due to the unfilled 4f orbitals of Yb which introduced the impurity level between the valence band and conduction band of Bi₂S₃, Yb-Bi₂S₃ exhibited admirable photo-to-current conversion efficiency under NIR light irradiation. The Yb-Bi₂S₃ modified electrode was employed to construct a NIR light-driven PEC sensor using an ATP-binding aptamer as the recognition element. When ATP was present, the photocurrent signal of the proposed aptasensor declined, owing to the formation of an ATP-aptamer complex which enhanced the steric hindrance of electron transfer on the electrode. Under optimal conditions, the sensor showed a sensitive response to ATP in the concentration range from 0.5 to 300 nmol L^-1 with a detection limit of 0.1 nmol L^-1. The proposed aptasensor exhibited high selectivity, good repeatability and desirable stability. Moreover, it was successfully applied to ATP detection in human serum samples.

Recent advances in degradation of organic pollutant in aqueous solutions using bismuth based photocatalysts: A review

Today, a major concern associated with the environment is the water pollution occurred due to the introduction of variety of persistent organic pollutants and residual dyes from different sources (e.g., dye and dye intermediates industries, paper and pulp industries, textile industries, tannery and craft bleaching industries, pharmaceutical industries, etc.) into our natural water resources. Recently, advanced oxidation processes (AOPs) by photocatalyst have garnered great attention as a new frontier promising eco-friendly and sustainable wastewater treatment technology. Utilization of the photocatalytic technology efficiently is significant for cleaner environment. Bismuth based photocatalyst have aroused widespread attention as a visible light responsive photocatalyst for waste water treatment due to their non-toxicity, low cost, modifiable morphology, and outstanding optical and chemical properties. In this review, we have dealt with the research progress on bismuth-based photocatalysts for waste water treatment. However, it seems to give limitation over pristine photocatalysts such as slow migration of charge carriers, charge carrier recombination, low visible light absorption, etc., Various bismuth based photocatalyst and its modifications via doping, heterojunction, Z-scheme etc., are discussed in detail. Further, the strategies adopted to improve the photocatalytic activity of bismuth based photocatalyst to improve the waste water treatment (mostly drugs and dyes) are critically reviewed. Also, we have discussed the bacterial inactivation by bismuth based photocatalyst. Finally, the challenges and future aspects against bismuth based photocatalyst are explored for further research.

Bi2S3 quantum dots in situ grown on MoS2 nanoflowers: An efficient electron-rich interface for photoelectrochemical N2 reduction

Photoelectrocatalysis is considered a green, environmentally friendly, sustainable technology for NH₃ synthesis. However, the low efficiency of ammonia synthesis is currently the primary problem in photoelectrochemical nitrogen reduction reactions (PEC NRR). Herein, a nanocomposite BQD/MS developed through the in-situ growth of Bi₂S₃ quantum dots (BQD) on MoS₂ (MS) nanoflowers was demonstrated as an efficient PEC NRR catalyst. Experimental results showed that the strong interaction between BQD and MS modulated the interfacial charge distribution and increased the electron density on the MS side. Meanwhile, the excellent structure of BQD/MS promoted the effective migration of photogenerated electrons from excited BQD to the MS surface. The electron-rich MS reaction interface was conducive to cleaving the stable NN bond and improving the N₂ reduction performance. As a result, the prepared BQD/15MS photocathode obtained an excellent Faradaic efficiency of 33.2% and an NH₃ yield of 18.5 μg h^-1 mg^-1, which was about three times that of bare MS.

Investigation of EG-Bi2S3 nanorods photocatalytic activity under visible light for dye degradation from aquatic system

Bi₂S₃, 5 ml EG-Bi₂S₃, and 10 ml EG-Bi₂S₃ were synthesized by employing solvothermal route. X-ray diffraction, UV-vis absorption, photoluminescence, Raman, scanning electron microscopic studies confirmed the structural, optical, morphological behaviors. The XRD pattern of Bi₂S₃, 5 ml EG-Bi₂S₃, and 10 ml EG-Bi₂S₃ was correlated well with JCPDS # 65-2435. The crystallite size was found to be 57, 49, and 40 nm. The photoluminescence spectra showed semiconducting property of prepared Bi₂S₃, 5 ml EG-Bi₂S₃, and 10 ml EG-Bi₂S₃. The absorption spectra of Bi₂S₃, 5 ml EG-Bi₂S₃, and 10 ml EG-Bi₂S₃ nanorods were well matched with the spectra of a previous report. The bandgap values of Bi₂S₃, 5 ml EG-Bi₂S₃, and 10 ml EG-Bi₂S₃ were calculated to be 1.56, 1.45, and 1.3 eV in reducing order. The morphology of Bi₂S₃, 5 ml EG-Bi₂S₃, and 10 ml EG-Bi₂S₃ samples showed the development of nanorods. The 10 ml EG-Bi₂S₃ sample showed better development of nanorods with the addition of ethylene glycol. The agglomeration was considerably reduced with the mixing of solvent. Bi₂S₃, 5 ml EG-Bi₂S₃, and 10 ml EG-Bi₂S₃ catalysts were added to the methylene blue dye solution and its photocatalytic properties were investigated by reducing toxic pollutants under light. The 10 ml EG-Bi₂S₃ sample with neutral pH and 0.1 g of catalyst was added and investigated which showed 86% of efficiency towards dye degradation. The narrow bandgap, defined morphology of 10 ml EG-Bi₂S₃, made a positive result towards efficient photocatalytic activity.

Straightforward Synthesis of SnO2/Bi2S3/BiOCl-Bi24O31Cl10 Composites for Drastically Enhancing Rhodamine B Photocatalytic Degradation under Visible Light

The pursuit of robust photocatalysts that can completely degrade organic contaminants with high performance as well as high energy efficiency, simplicity in preparation, and low cost is an appealing topic that potentially promotes photocatalysts for being used widely. Herein, we introduce a new and efficient SnO2/Bi2S3/BiOCl-Bi24O31Cl10 (SnO2/Bi2S3-Bi25) composite photocatalyst by taking advantage of the robust, simple, and potentially scalable one-pot synthesis, including the hydrothermal process followed by thermal decomposition. Interestingly, we observed the formation of BiOCl-Bi24O31Cl10 (abbreviated as Bi25) heterojunctions derived from reactions between Bi2S3 and SnCl4·5H2O precursor solutions under the hydrothermal condition and thermal decomposition of BiOCl. This Bi25 heterojunction acts as an interface to reduce the recombination of photogenerated electron-hole (e--h+) pairs as well as to massively enhance the visible light harvesting, thereby significantly enhancing the photocatalytic degradation performance of the as-prepared composite photocatalyst. In detail, the photocatalytic degradation of Rhodamine B (RhB) activated by visible light using 15% SnO2/Bi2S3-Bi25 shows the efficiency of 80.8%, which is superior compared to that of pure Bi2S3 (29.4%) and SnO2 (0.1%). The SnO2/Bi2S3-Bi25 composite photocatalyst also presents an excellent photostability and easy recovery from dye for recycling. The trapping test revealed that the photogenerated holes play a crucial factor during the photocatalytic process, whereas superoxide radicals are also formed but not involved in the photocatalytic process. Successful fabrication of SnO2/Bi2S3-Bi25 composite photocatalysts via a straightforward method with drastically enhanced photocatalytic performance under visible light activation would be useful for practical applications.

Morphological variations in Bi2S3 nanoparticles synthesized by using a single source precursor

A simple solvothermal decomposition of bismuth dithiocarbamate complex in oleylamine, oleic acid, and hexadecylamine at 180 °C, yielded bismuth sulphide nanomaterials of different morphologies represented as Bi₂S₃(OAm), Bi₂S₃(OAc) and Bi₂S₃(HDA) respectively. The bismuth complex, used as the single source precursor, was synthesized and characterised by elemental analysis, FTIR, and NMR spectroscopic techniques. The spectroscopic and micro analysis confirmed the proposed compound, while the as-prepared nanoparticles were characterized using UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive spectrometer (EDS). The effects of the different solvent media on the structural properties of the obtained Bi₂S₃ were investigated. An orthorhombic phase bismuthinite of varying intensities were obtained, with an indication that a bias of orientations existed in the (2 1 1) crystallographic planes in the Bi₂S₃(OAm) compared to the characteristic (1 3 0) diffraction peak of Bi₂S₃. The microscopic analysis showed a correlation between the nanoparticles' morphology and the type of solvent used, which also implied that the properties of Bi₂S₃ were affected by the solvent medium.

Fabrication of vessel-like biochar-based heterojunction photocatalyst Bi2S3/BiOBr/BC for diclofenac removal under visible LED light irradiation: Mechanistic investigation and intermediates analysis

In this work, a novel, economical and effective vessel-like biochar-based photocatalyst Bi₂S₃/BiOBr/BC was synthesized by a facile one-pot solvothermal method for the first time. A series of characterization analyses demonstrated the successful preparation of photocatalyst Bi₂S₃/BiOBr/BC. Furthermore, diclofenac (DCF) as the target contaminant was applied to elucidate the enhanced photocatalytic performance (93.65%, 40 min) under energy-saving visible LED light irradiation. Comparison experiments among different photocatalysts and photoelectrochemical tests results illustrated that excellent photocatalytic performance of Bi₂S₃/BiOBr/BC 10% might be attributed to the electrons transfer of biochar and higher charge separation efficiency of heterojunction structure. Besides, lower electrical energy per order value indicated photocatalyst/visible LED light system was more energy-saving. Proper photocatalyst dosage (0.6 g/L) and relatively acidic water environment (pH = 5.0) would be beneficial to DCF photodegrdation by Bi₂S₃/BiOBr/BC. Good reusability and stability of Bi₂S₃/BiOBr/BC were verified via five consecutive recycle experiments. Furthermore, the role of active species was determined through trapping experiments and O₂- and h⁺ dominated the photodegradation reaction to mineralize DCF molecules. Eleven main intermediates and four possible photodegradation pathways were proposed by HRMS analysis. Accordingly, photocatalyst Bi₂S₃/BiOBr/BC would provide potential technical support for emerging pollutant removal in water matrix.

Facile strategy for the fabrication of noble metal/ZnS composites with enhanced photocatalytic activities

The introduction of noble metal nanoparticles to photocatalysts can effectively improve the separation efficiency of the photogenerated electron–holes. Therefore, noble metal/ZnS composites were synthesized using a low-temperature solid-phase chemical method with sodium borohydride as the reducing agent. The characterization results showed that the noble metal/ZnS composites have been successfully obtained and that the noble metals were distributed on the surface of ZnS. The catalytic results suggested that the composites exhibited improved activity after introduction of noble metals, which can be attributed to the rapid migration of carriers and the enhancement of the light absorption, mainly owing to the tight combination between the ZnS and noble metals and the plasmon resonance effect of the noble metals. The catalytic mechanism was explored by using photoluminescence spectroscopy, photocurrent spectra, valence band X-ray photoelectron spectroscopy (XPS-VB) spectra and capture agent experiments, and a possible mechanism was proposed. This work provides a new strategy for the high-volume synthesis of noble metal-based composite photocatalysts, which could be helpful for sustainable development.

The introduction of noble metal nanoparticles to photocatalysts can effectively improve the separation efficiency of the photogenerated electron–holes.

Ultrasonic irradiation-assisted synthesis of Bi2S3 nanoparticles in aqueous ionic liquid at ambient condition

In this work, an easy, fast and environmentally friendly method to obtain Bi₂S₃ nanostructures with sphere-like morphology is introduced. The promising material was successfully synthesized by a sonochemical route in 20% 1-ethyl-3-methylimidazolium ethyl sulfate [EMIM][EtSO₄] ionic liquid solution (IL). Morphological studies by electron microscopy (SEM and TEM) show that the use of IL in the synthesis of Bi₂S₃ favors the formation of nanocrystals non-agglomerated. Micro Raman and energy dispersive X-ray spectroscopy (EDXS) were used to determine the composition and purity of the synthesized material. X-ray powder diffraction (XRD) and selective area electron diffraction (SAED) revealed that ultrasonic radiation accelerated the crystallization of Bi₂S₃ into orthorhombic bismuthinite structure. The band gap calculated from the diffuse reflectance spectra (DRS) was found to be 1.5eV.

Controllable one-pot synthesis of a nest-like Bi2WO6/BiVO4 composite with enhanced photocatalytic antifouling performance under visible light irradiation

In this study, a novel visible-light-sensitive Bi2WO6/BiVO4 composite photocatalyst was controllably synthesized through a facile one-pot hydrothermal method. The Bi2WO6/BiVO4 composite exhibited a perfect nest-like hierarchical microsphere structure, which was constructed by the self-assembly of nanoplates with the assistance of polyvinylpyrrolidone (PVP). The growth mechanism of the Bi2WO6/BiVO4 composite and the effect of its structure on its photocatalytic performance was investigated and proposed. Experimental results showed that the Bi2WO6/BiVO4 composites displayed enhanced photocatalytic antifouling activities under visible light irradiation compared to pure Bi2WO6 and BiVO4. Bi2WO6/BiVO4-1 exhibited the best photocatalytic antifouling performance, and almost all (99.99%) Pseudomonas aeruginosa (P. aeruginosa), Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) bacteria were killed within 30 min. Moreover, the Bi2WO6/BiVO4-1 composite exhibited excellent stability and reusability in the cycled experiments. The photocatalytic antifouling mechanism was proposed based on the active species trapping experiments, revealing that the photo-induced holes (h(+)) and hydroxyl radicals (˙OH) could attack the cell wall and cytoplasmic membrane directly and lead to the death of bacteria. The obviously enhanced photocatalytic activity of the Bi2WO6/BiVO4-1 composite could be mainly attributed to the formation of heterojunctions, accelerating the separation of photo-induced electrons and holes. Furthermore, the large BET surface area combined with the wide photoabsorption region further improved the photocatalytic performance of the Bi2WO6/BiVO4-1 composite. This study provides a new strategy to develop novel composite photocatalysts with enhanced photocatalytic performance for marine antifouling and water purification.

Hierarchical photocatalysts

The design, fabrication, performance and applications of hierarchical semiconductor photocatalysts are thoroughly reviewed and apprised.

Green synthesis of BiOBr modified Bi2O2CO3 nanocomposites with enhanced visible-responsive photocatalytic properties

BiOBr/Bi₂O₂CO₃ nanocomposites with mesh-like structures were simply synthesized by a green solid-state chemical reaction route with no extra template or surfactant.

Synthesis of BiPO4/Bi2S3 Heterojunction with Enhanced Photocatalytic Activity under Visible-Light Irradiation

BiPO4/Bi2S3 photocatalysts were successfully synthesized by a simple two-step hydrothermal process, which involved the initial formation of BiPO4 rod and then the attachment of Bi2S3 through ion exchange. The as-synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV-vis diffuse reflectance spectra (UV-vis DRS). It was found that BiPO4 was regular rods with smooth surfaces. However, BiPO4/Bi2S3 heterojunction had a rough surface, which could be attributed to the attachment of Bi2S3 on the surface of BiPO4 rods. The BiPO4/Bi2S3 composite exhibited better photocatalytic performance than that of pure BiPO4 and Bi2S3 for the degradation of methylene blue (MB) and Rhodamine B (RhB) under visible light. The enhanced photocatalytic performance could be ascribed to synergistic effect of BiPO4/Bi2S3 heterojunction, in which the attached Bi2S3 nanoparticles could improve visible-light absorption and the BiPO4/Bi2S3 heterojunction suppressed the recombination of photogenerated electron-hole pairs. Our work suggested that BiPO4/Bi2S3 heterojunction could be a potential photocatalyst under visible light.

One-step synthesis of Bi2WO6/Bi2O3 loaded reduced graphene oxide multicomponent composite with enhanced visible-light photocatalytic activity

Schematic diagram of charge separation in visible-light irradiation and the energy band mechanism of enhanced photocatalytic activity of BWO@R.

CuS–Bi2S3 hierarchical architectures: controlled synthesis and enhanced visible-light photocatalytic performance for dye degradation

Novel CuS–Bi₂S₃ heterojunctions were fabricated by a one-step solvothermal method using glycol as solvent and l-lysine as structure-directing reagent. The composites showed enhanced photocatalytic activity towards dye degradation under visible light.

Controlled assembly of Bi2S3 architectures as Schottky diode, supercapacitor electrodes and highly efficient photocatalysts

Bi₂S₃ microflowers were controllably fabricated, and their improved electrochemical and photocatalytic properties were observed.