In Situ Synthesis of Bi2S3/BiFeO3 Nanoflower Hybrid Photocatalyst for Enhanced Photocatalytic Degradation of Organic Pollutants

Photocatalytic degradation of Malachite Green oxalate (MG) in a water body is of significant importance to our health protection, as it could cause various serious diseases. However the photocatalytic activity of most catalysts is still unsatisfactory, due to the poor reactive oxygen species production as a result of sluggish charge separation. Here, innovative nanoflower-shaped Bi2S3/BiFeO3 heterojunctions are prepared via a facile sol-gel method, exhibiting an enhanced reactive oxygen species generation, which leads to the excellent photocatalytic performance toward MG degradation. We verify that interfacing BiFeO3 with Bi2S3 could form a fine junction and offers a built-in field to speed up charge separation at the junction area; as a result, this shows much higher charge separation efficiency. By virtue of the aforementioned advantages, the as-prepared Bi2S3/BiFeO3 heterojunctions exhibit excellent photocatalytic performance toward MG degradation, where more than 99% of MG is removed within 2 h of photocatalysis. The innovative design of nanoflower-like Bi2S3/BiFeO3 heterojunctions may offer new viewpoints in designing highly efficient photocatalysts for environmentally related applications.

Strategies for enhancing performance of perovskite bismuth ferrite photocatalysts (BiFeO3): A comprehensive review

Organic pollutants pose a significant threat to water safety, and their degradation is of paramount importance. Photocatalytic technology has emerged as a promising approach for environmental remediation, and Bismuth ferrite (BiFeO3) has been shown to exhibit remarkable potential for photocatalytic degradation of water pollutants, with its excellent crystal structure properties and visible light photocatalytic activity. This review presents an overview of the crystal properties and photocatalytic mechanism of perovskite bismuth ferrite (BiFeO3), as well as a summary of various strategies for enhancing its efficiency in photocatalytic degradation of organic pollutants. These strategies include pure phase preparation, microscopic modulation, composite modification of BiFeO3, and the integration of Fenton-like reactions and external field-assisted methods to improve its photocatalytic performance. The review emphasizes the impact of each strategy on photocatalytic enhancement. By providing comprehensive strategies for improving the efficiency of BiFeO3 photocatalysis, this review inspires new insights for efficient degradation of organic pollutants using BiFeO3 photocatalysis and contributes to the development of photocatalysis in environmental remediation.

Removal of persistent acetophenone from industrial waste-water via bismuth ferrite nanostructures

Increasing water pollution is a severe problem in densely industrialized countries. Nanomaterials provide strong potentials for the efficient elimination of organic pollutants due to their beneficial properties. Advancement in water purification is required to more efficiently remove the emerging organic contaminants, especially in pharmaceuticals wastes such as acetophenone, which shows high solubility in industrial wastewaters. Bismuth ferrite-based nanostructures were fabricated using a novel double solvent sol-gel method. The phase purity and crystallinity of bismuth ferrite were confirmed using XRD and further endorsed by TEM analysis. The SEM and XPS were used to study the particle sizes and presence of co-dopants on the Bi and Fe-sites of bismuth ferrite. After co-doping, the band-gap engineering of pure bismuth ferrites was accomplished by reducing it from 2.06 eV to 1.45 eV, likely attributing to the creation of shallow traps for the incoming photo-generated charge carriers. In particular, the Bi_0.90Gd_0.10Fe_0.95Sn_0.05 and Bi_0.95Sm_0.05Fe_0.75Mn_0.25 successfully eliminated up to 98% of acetophenone from polluted water in 3 h by irradiation of visible-light. These results reveal the suitability of the co-doped bismuth ferrites photocatalysts for the practical removal of pharmaceutical contaminants in hazardous industrial wastewater. The photodegradation of acetophenone by bismuth ferrite nanostructures with potentially long-lasting reusability demonstrate its potential as an advanced photocatalyst for wastewater treatment.

Bismuth-based complex oxides for photocatalytic applications in environmental remediation and water splitting: A review

As an emerging group of visible-light-driven photocatalysts, bismuth-based complex oxides have attracted considerable attention owing to their outstanding photo-oxidation ability and high performance in decomposition of organic contaminants and water oxidation via photocatalytic processes. However, the relatively low level of the conduction band limits their further application in photocatalytic hydrogen evolution and overall water splitting processes. In this paper, three representative and most-studied Bi-based complex oxides of BiOX (X = Cl, Br, I)/BiFeO₃/Bi₂WO₆ are discussed mainly for environmental pollutants degradation and oxygen generation from water splitting. We present a comprehensive overview of their fundamental compositions, electronic structures and synthesis strategies. On the basis of analyzing the structural-property-activity relationships, detailed approaches for enhancement of their photocatalytic performance have been addressed and compared including morphology/facets control, heterostructures construction and introduction of oxygen vacancies. In addition, several techniques such as engineering energy band and building a Z-scheme system have been proposed to modulate the energy band positions of the photocatalysts and overcome the bottleneck to realize overall water splitting into H₂ and O₂ simultaneously. Finally, remarks on the current challenges, research directions and future perspectives are presented to provide guidance for designing and configuring highly efficient solar-light-driven photocatalysts in the field of environmental purification and energy conversion.

Strategies for preparing TiO2/CuS nanocomposites with cauliflower-like protrusions for photocatalytic water purification

A simple and controllable method was developed to prepare TiO2/CuS nanocomposites with high photocatalytic efficiency.

Facile Synthesis of BiVO4@ZIF-8 Composite with Heterojunction Structure for Photocatalytic Wastewater Treatment

Water pollution has always been a serious problem across the world; therefore, facile pollutant degradation via light irradiation has been an attractive issue in the field of environmental protection. In this study, a type of Zn-based metal–organic framework (ZIF−8)-wrapped BiVO₄ nanorod (BiVO₄@ZIF−8) with high efficiency for photocatalytic wastewater treatment was synthesized through a two-step hydrothermal method. The heterojunction structure of BiVO₄@ZIF−8 was confirmed by morphology characterization. Due to the introduction of mesoporous ZIF−8, the specific surface area reached up to 304.5 m²/g, which was hundreds of times larger than that of pure BiVO₄ nanorods. Furthermore, the band gap of BiVO₄@ZIF−8 was narrowed down to 2.35 eV, which enabled its more efficient utilization of visible light. After irradiation under visible light for about 40 min, about 80% of rhodamine B (RhB) was degraded, which was much faster than using pure BiVO₄ or other BiVO₄-based photocatalysts. The synergistic photocatalysis mechanism of BiVO₄@ZIF−8 is also discussed. This study might offer new pathways for effective degradation of wastewater through facile design of novel photocatalysts.

Synergy of ferroelectric polarization and oxygen vacancy to promote CO2 photoreduction

Solar-light driven CO2 reduction into value-added chemicals and fuels emerges as a significant approach for CO2 conversion. However, inefficient electron-hole separation and the complex multi-electrons transfer processes hamper the efficiency of CO2 photoreduction. Herein, we prepare ferroelectric Bi3TiNbO9 nanosheets and employ corona poling to strengthen their ferroelectric polarization to facilitate the bulk charge separation within Bi3TiNbO9 nanosheets. Furthermore, surface oxygen vacancies are introduced to extend the photo-absorption of the synthesized materials and also to promote the adsorption and activation of CO2 molecules on the catalysts' surface. More importantly, the oxygen vacancies exert a pinning effect on ferroelectric domains that enables Bi3TiNbO9 nanosheets to maintain superb ferroelectric polarization, tackling above-mentioned key challenges in photocatalytic CO2 reduction. This work highlights the importance of ferroelectric properties and controlled surface defect engineering, and emphasizes the key roles of tuning bulk and surface properties in enhancing the CO2 photoreduction performance.

In situ Synthesis of Au-Induced Hierarchical Nanofibers/Nanoflakes Structured BiFeO3 Homojunction Photocatalyst With Enhanced Photocatalytic Activity

In order to further improve the photocatalytic performance of BiFeO₃ (BFO), novel Au-induced hierarchical nanofibers/nanoflakes structured BiFeO₃ homojunctions (Au_x-BFO, x = 0, 0. 6, 1.2, 1.8, 2.4 wt%) were in situ synthesized through a simple reduction method with assist of sodium citrate under the analogous hydrothermal environment. The effect of loading amount of Au nanoparticles (NPs) on the physicochemical properties and photocatalytic activity was investigated in detail. The Au_1.2-BFO NFs sample show the best photocatalytic activity (85.76%), much higher than that for pure BFO samples (49.49%), mainly due to the hierarchical nanofibers/nanoflakes structured homojunction, the surface plasmon resonance (SPR) effect of Au NPs, as well as the presence of defects (Fe²⁺/Fe³⁺ pairs and oxygen vacancy). Furthermore, the possible formation mechanism of the unique homojunction and the enhanced photocatalytic mechanism for the degradation of methylene blue (MB) dye are proposed. It is proven that holes (h⁺) play the decisive role in the photocatalytic process. The present work provides a fascinating way to synthesize efficient homojunctions for the degradation of organic pollutes.

Polystyrene-heterojunction semiconductor composite spheres prepared by a hydrothermal synthesis process: a recyclable photocatalyst under visible light irradiation for removing organic dyes from aqueous solution

The composite photocatalyst can absorb both insoluble and soluble organic dyes and can be recycled easily by filtering.

Ferromagnetic-like behaviour in bismuth ferrite films prepared by electrodeposition and subsequent heat treatment

BiFeO₃ films are achieved by electrodeposition followed by heat-treatment in air. The films show ferromagnetic-like behaviour at room temperature.

BiFeO3 nanorings synthesized via AAO template-assisted pulsed laser deposition and ion beam etching

Well-ordered BiFeO₃ nanorings with epitaxial structure, strong ferroelectricity and polarization reversal have been fabricated using this novel and facile method.

Particulates vs. fibers: dimension featured magnetic and visible light driven photocatalytic properties of Sc modified multiferroic bismuth ferrite nanostructures

We report the magnetic and visible light driven photocatalytic properties of scandium (Sc) substituted bismuth ferrite (BSFO) particulate and fiber nanostructures. An increasing concentration of Sc was found to reduce the crystallite size, particle size and band gap energy of the BSFO nanostructures, which was evident from X-ray diffraction, field emission scanning electron microscopy and UV-Visible diffuse reflectance spectroscopy analysis respectively. The temperature dependent magnetic studies carried out using a SQUID magnetometer suggested that the origin of the magnetic properties in the pure BFO system could be the emergence of an antiferromagnetic-core/ferromagnetic-shell like structure, in contrast to the modified spin canted structures in the case of the BSFO nanostructures. The observed photocatalytic efficiency was attributed to the enhanced band bending process and recombination resistance in the BSFO nanostructures. For a comparative study, the photocatalytic activities of some selected compositions were also investigated under simulated solar light along with natural solar light.

Sucrose-templated nanoporous BiFeO3 for promising magnetically recoverable multifunctional environment-purifying applications: adsorption and photocatalysis

​Exhibited high magnetic performance (M_s = 6.37 emu g⁻¹) and a favorable magnetic recycling ratio, nanoporous BiFeO₃ materials can be regarded as a candidate for promising recoverable multifunctional environment-purifying applications in the future.

Mesoporous template-free gyroid-like nanostructures based on La and Mn co-doped bismuth ferrites with improved photocatalytic activity

Template-free and gyroid-like mesoporous nanostructures of La and Mn co-doped bismuth ferrites were fabricated using a simple and low-cost double solvent sol–gel technique.

Compliments of confinements: substitution and dimension induced magnetic origin and band-bending mediated photocatalytic enhancements in Bi(1-x)Dy(x)FeO3 particulate and fiber nanostructures

The manifestation of substitution and dimension induced modifications in the magnetic origin and photocatalytic properties of Dy substituted bismuth ferrite (BDFOx) particulate and fiber nanostructures are reported herein. A gradual transformation from rhombohedral to orthorhombic structure is observed in BFO with the increasing concentration of Dy. Substitution induced size reduction in particulate and fiber nanostructures is evident from the scanning and transmission electron micrographs. Energy band structures of both particulate and fiber nanostructures are considerably influenced by the Dy substitution, which is ascribed to the formation of new energy states underneath the conduction band of host BFO. Field dependent and temperature dependent magnetic studies reveal that the origin of magnetism in pure BFO systems is due to the antiferromagnetic-core/ferromagnetic-shell like structure. On the other hand, it gets completely switched into 'canted' spin structures due to the substitution induced suppression of cycloidal spins in BFO, which is found to be the origin of magnetism in BDFOx particulate and fiber nanostructures. The visible light driven photocatalytic activity of BDFOx nanostructures is found to be enhanced with increasing concentration of Dy. Substitution induced band gap modification, semiconductor band bending phenomenon mediated charge transfer and reduced recombination resistances are attributed to the observed photocatalytic enhancements in these nanostructures.

RV, Balakumar S. Versatility of electrospinning in the fabrication of fibrous mat and mesh nanostructures of bismuth ferrite (BiFeO3) and their magnetic and photocatalytic activities

This study demonstrates the fabrication and properties of electrospun bismuth ferrite (BiFeO₃) fiber mat and fibrous mesh nanostructures consisting of aligned and random fibers respectively.

BiFeO3/YSZ bilayer electrolyte for low temperature solid oxide fuel cell

Highly crystalline perovskite BiFeO₃ is obtained by a facile solution method. We have reported that the YSZ/BFO electrolyte with 17 μm/30 μm thickness, respectively, showed a maximum power density of 165 mW cm⁻² and open-circuit voltage of 0.75 V at 650 °C.

Nanostructured Bi(1−x)Gd(x)FeO3 – a multiferroic photocatalyst on its sunlight driven photocatalytic activity

We report the manifestation of sunlight driven photocatalytic activity in the nanostructured Gd substituted bismuth ferrite (BiFeO₃) multiferroic photocatalyst.