Efficient photocatalytic degradation of perfluorooctanoic acid by bismuth nanoparticle modified titanium dioxide

Perfluorooctanoic acid (PFOA) is potentially toxic and exceptionally stable attributed to its robust CF bond, which is hard to be removed by UV/TiO2 systems. In this research, bismuth nanoparticle (Bi NP) modified titanium oxides (Bi/TiO2) were synthesized by a simple photochemical deposition-calcination method and were applied as photocatalysts for the first time to degrade PFOA. The removal rate of 50 mg/L PFOA reached 99.3 % with 58.6 % defluorination rate after 30 min of irradiation via a mercury lamp. Bi/TiO2 exhibited superior performance in PFOA degradation compared to commercial photocatalysts (TiO2, Ga2O3, Bi2O3 and In2O3). In addition, Bi/TiO2 showed high degradation activity under actual sunlight, achieved 100 % removal rate and 59.3 % defluorination rate within 2 h. Bi NPs increase the light trapping ability of Bi/TiO2 and promote the separation of photogenerated electron-hole pairs via local surface plasmon resonance (LSPR) effect, which results in more photogenerated holes (h+) and hydroxyl radicals (OH). Combined with DFT calculations and intermediate detections, the degradation reaction is initiated from the oxidation of the PFOA carboxyl group via h+, followed by the loss of the CF2 unit step by step with the participation of OH. This work presents a novel approach for the practical implementation of TiO2-based photocatalysts to achieve highly efficient photocatalytic degradation of perfluorocarboxylic acids (PFCAs).

Construction of p-n-p nano heterojunction through coupling La2O3, (BiO)2CO3 and Ag3PO4 for effective photocatalytic degradation of doxycycline: Insights into mechanism, pathway and intermediate toxicity evaluation

The present work is centred around the development of La2O3/(BiO)2CO3/Ag3PO4 (LBA), a p-n-p nano-heterojunction to photodegrade doxycycline under visible light irradiation. Here, ultrasonication assisted co-precipitation method was employed to synthesize the photocatalyst. The photocatalyst was characterized using different analysis such as SEM, TEM, elemental mapping, XRD, XPS, FTIR, Raman, BET, DRS, PL and EIS which confirmed the successful fabrication of LBA and their excellent ability to refrain the e-/h+ recombination owing to the construction of the heterojunction. LBA was found to degrade DOX by 91.75 % with the high mineralization of 87.23%. The impact of the reaction parameters influencing the photodegradation process including the concentration of the NCs and DOX, pH and the influence of the commonly present anions were studied. The stability and reusability of the LBA was assessed through subjecting it to four cycles of photodegradation of DOX. In addition, the recovered LBA was characterized through XPS and XRD analysis to confirm the particles stability and reusability. The active participation of the photogenerated charges and the reactive oxygen species were identified through the scavenging assay and ESR analysis. Further, GC-MS/MS analysis was performed to put forward a plausible photodegradation pathway. The toxicity of the end products as well as the intermediates was predicted through ECOSAR software.

Fabrication of the flower-like Z-scheme heterojunction photocatalyst Bi-BiOI/UiO 66 for enhanced photodegradation of acetaminophen in simulated wastewater

Acetaminophen is a representative contaminant of emerging persistent organic pollutants that can cause environmental problems when it enters municipal wastewater. An innovative flower-like Z-scheme photocatalyst Bi-BiOI/UiO 66 heterojunction composite was designed and constructed via a one-step solvothermal method. Investigations demonstrated that the Z-scheme structure strongly contributes to increasing the degradation efficiency of micropollutants. The results indicate that the bandgap energy (Eg) of the Bi-BiOI/UiO 66 composite decreases significantly from 3.22 eV to 2.43 eV, in comparison with that of pure copper-based UiO 66. Under suitable conditions (5 mg/L Ace, pH 3, 0.05 g/L), the organic pollutants in the water can be removed completely. A k value of 5.67 × 10-2 min-1 for the Bi-BiOI/UiO 66 heterojunction composite was found to effectively represent the acetaminophen photodegradation process. The reaction mechanism of acetamide in aqueous solution is also discussed. The Bi in Bi-BiOI can use surface plasmon resonance to form an electric field and accelerate the separation of photogenerated electrons and holes. This study highlights the potential of a novel photocatalyst for practical application.

Ultra-sensitive photoelectrochemical biosensor for determination of African swine fever virus based on surface plasmon resonance

Sensitive and specific detection of African swine fever virus (ASFV) is crucial for agricultural production and economic development due to the mortality and infectivity. In this study, a bismuth induced enhanced photoelectrochemical (PEC) biosensor based on in-situ loop mediated isothermal amplification (LAMP) was constructed using deposited bismuth nanoparticles loaded bismuth oxycarbonate (Bi/(BiO)2CO3) as photoactive material, using primers designed according to LAMP as recognition elements, and using in-situ LAMP to achieve nucleic acid amplification of target genes. As the Bi induced surface plasmon resonance (SPR) effect, enhanced light captures and effective electron hole separation, it could effectively enhance the photoelectric activity, so the prepared Bi/(BiO)2CO3 nanohybrid had higher photocurrent intensity and good stability. The constructed PEC biosensor has realized the detection of ASFV in real samples with good sensitivity, specificity and repeatability. In the range from 1.0 × 10-13 to 1.0 × 10-7 g/L, the photoelectric current decreased with the increase of the concentration of ASFV, and the detection limit was 3.0 × 10-14 g/L (about 0.048 copies/μL). Combining the advantages of LAMP with the excellent performance of PEC, it provides a simple, economical and efficient method for nucleic acid diagnosis, and also provides a new idea for biosensor detection.

Dual modification based on electrostatic repulsion of bentonite and SPR effect of Bi facilitate charge transfer of Bi2WO6 for antibiotics degradation

Development of efficient photocatalysts is vital for light-driven removal of refractory antibiotics. Herein, Bi₂WO₆ microspheres were successfully anchored on the surface of bentonite, and metallic Bi was reduced in-situ by a one-step solvothermal method. Notably, the Bi/Bi₂WO₆/BT with a mass ratio of 0.15:1:0.1 exhibited the best photocatalytic activity toward degradation of tetracycline (TC) and ciprofloxacin (CIP) after 120 min of visible light irradiation, and their reaction rate constants were 8.0 and 5.5 folds higher than that of pristine Bi₂WO₆, respectively. The boosted photocatalytic activity over Bi/Bi₂WO₆/BT was ascribed to the establishment of electrostatic repulsion and SPR effect, which synergistically promoted charges transfer, thus achieving more h⁺ and ·O₂^- radical generation. Moreover, possible TC and CIP degradation pathways over Bi/Bi₂WO₆/BT were proposed based on the identified intermediates, and most of the intermediates were less toxic than TC and CIP. The study provides options to develop high-efficiency photocatalytic composites for contaminants elimination using semiconductors and readily available bentonite.

Bismuth-coated 80S15C bioactive glass scaffolds for photothermal antitumor therapy and bone regeneration

Background: Malignant bone tumors usually occur in young people and have a high mortality and disability rate. Surgical excision commonly results in residual bone tumor cells and large bone defects, and conventional radiotherapy and chemotherapy may cause significant side effects. In this study, a bifunctional Bi-BG scaffold for near-infrared (NIR)-activated photothermal ablation of bone tumors and enhanced bone defect regeneration is fabricated. Methods: In this study, we prepared the Bi-BG scaffold by in-situ generation of NIR-absorbing Bi coating on the surface of a 3D-printing bioactive glass (BG) scaffold. SEM was used to analyze the morphological changes of the scaffolds. In addition, the temperature variation was imaged and recorded under 808 nm NIR laser irradiation in real time by an infrared thermal imaging system. Then, the proliferation of rat bone mesenchymal stem cells (rBMSCs) and Saos-2 on the scaffolds was examined by CCK-8 assay. ALP activity assay and RT-PCR were performed to test the osteogenic capacity. For in vivo experiments, the nude rat tumor-forming and rat calvarial defect models were established. At 8 weeks after surgery, micro-CT, and histological staining were performed on harvested calvarial samples. Results: The Bi-BG scaffolds have outstanding photothermal performance under the irradiation of 808 nm NIR at different power densities, while no photothermal effects are observed for pure BG scaffolds. The photothermal temperature of the Bi-BG scaffold can be effectively regulated in the range 26-100°C by controlling the NIR power density and irradiation duration. Bi-BG scaffolds not only significantly induces more than 95% of osteosarcoma cell death (Saos-2) in vitro, but also effectively inhibit the growth of bone tumors in vivo. Furthermore, they exhibit excellent capability in promoting osteogenic differentiation of rBMSCs and finally enhance new bone formation in the calvarial defects of rats. Conclusion: The Bi-BG scaffolds have bifunctional properties of photothermal antitumor therapy and bone regeneration, which offers an effective method to ablate malignant bone tumors based on photothermal effect.

The Strengthened Photocatalytic NOx Removal of Composites Bi4O5Br2/BiPO4: The Efficient Regulation of Interface Carriers by Integrating a Wide-Bandgap Ornament

A series of binary composites Bi₄O₅Br₂/BiPO₄ (PBX) was fabricated through a simple mechanical ball milling protocol. Relevant microstructural, morphological, and optical properties were thoroughly analyzed via various techniques. The integration of both components was confirmed to produce heterojunction domains at the phase boundaries. Upon exposure to visible light irradiation, the as-achieved PBX series possessed the reinforced photocatalytic NO_x removal efficiencies and the weakened generation of toxic intermediate NO₂ in comparison to both bare components, chiefly attributed to the efficient transport and separation of carriers and boosted production of superoxide radicals (·O₂^-) through the combination of a wide-bandgap ornament BiPO₄ as an electron acceptor. In particular, the composite PB5 with the optimal phase composition exhibited the highest NO_x removal of 40% with the lowest NO₂ formation of 40 ppb among all tested candidates. According to the band structures' estimation and reactive species' detection, a reasonable mechanism was ultimately proposed to describe the migration of charge carriers and the enhancement of photocatalytic performance.

Photocatalytic degradation of GenX in water using a new adsorptive photocatalyst

GenX, the ammonium salt of hexafluoropropylene oxide dimer acid, has been used as a replacement for perfluorooctanoic acid. Due to its widespread uses, GenX has been detected in waters around the world amid growing concerns about its persistence and adverse health effects. As relevant regulations are rapidly evolving, new technologies are needed to cost-effectively remove and degrade GenX. In this study, we developed an adsorptive photocatalyst by depositing a small amount (3 wt.%) of bismuth (Bi) onto activated-carbon supported titanate nanotubes, Bi/TNTs@AC, and tested the material for adsorption and subsequent solid-phase photodegradation of GenX. Bi/TNTs@AC at 1 g/L was able to adsorb GenX (100 µg/L, pH 7.0) within 1 h, and then degrade 70.0% and mineralize 42.7% of pre-sorbed GenX under UV (254 nm) in 4 h. The efficient degradation also regenerated the material, allowing for repeated uses without chemical regeneration. Material characterizations revealed that the active components of Bi/TNTs@AC included activated carbon, anatase, and Bi nanoparticles with a metallic Bi core and an amorphous Bi₂O₃ shell. Electron paramagnetic resonance spin-trapping, UV-vis diffuse reflectance spectrometry, and photoluminescence analyses indicated the superior photoactivity of Bi/TNTs@AC was attributed to enhanced light harvesting and generation of charge carriers due to the UV-induced surface plasmon resonance effect, which was enabled by the metallic Bi nanoparticles. ^•OH radicals and photogenerated holes (h⁺) were responsible for degradation of GenX. Based on the analysis of degradation byproducts and density functional theory calculations, photocatalytic degradation of GenX started with cleavage of the carboxyl group and/or ether group by ^•OH, h⁺, and/or e_aq^-, and the resulting intermediates were transformed into shorter-chain fluorochemicals following the stepwise defluorination mechanism. Bi/TNTs@AC holds the potential for more cost-effective degradation of GenX and other per- and polyfluorinated alkyl substances.

Non-Noble Plasmonic Metal-Based Photocatalysts

Solar-to-chemical energy conversion via heterogeneous photocatalysis is one of the sustainable approaches to tackle the growing environmental and energy challenges. Among various promising photocatalytic materials, plasmonic-driven photocatalysts feature prominent solar-driven surface plasmon resonance (SPR). Non-noble plasmonic metals (NNPMs)-based photocatalysts have been identified as a unique alternative to noble metal-based ones due to their advantages like earth-abundance, cost-effectiveness, and large-scale application capability. This review comprehensively summarizes the most recent advances in the synthesis, characterization, and properties of NNPMs-based photocatalysts. After introducing the fundamental principles of SPR, the attributes and functionalities of NNPMs in governing surface/interfacial photocatalytic processes are presented. Next, the utilization of NNPMs-based photocatalytic materials for the removal of pollutants, water splitting, CO₂ reduction, and organic transformations is discussed. The review concludes with current challenges and perspectives in advancing the NNPMs-based photocatalysts, which are timely and important to plasmon-based photocatalysis, a truly interdisciplinary field across materials science, chemistry, and physics.

Construction of plasmonic Bi/Bismuth oxycarbonate/Zinc bismuth oxide ternary heterojunction for enhanced charge carrier separation and photocatalytic performances

In this work, a novel plasmonic ternary Bi/Bismuth oxycarbonate/Zinc bismuth oxide (Bi-Bi₂O₂CO₃-ZnBi₂O₄) is synthesized synergistically by a one-step hydrothermal method. The results show that the metallic Bi spheres and ZnBi₂O₄ nanoparticles are uniformly distributed on the surface of flower-like Bi₂O₂CO₃ layer. Compared with the bare ZnBi₂O₄ and Bi-Bi₂O₂CO₃, the ternary Bi-Bi₂O₂CO₃-ZnBi₂O₄ heterojunction displays a significantly improved solar energy harvesting efficiency and enhanced photocatalytic degradation activity for environmental organic pollutants. The degradation efficiency of organics reaches to 98.4% under simulated solar light illumination. The degradation kinetics indicates that the photocatalytic reaction rate constant of ternary system is about 4.4 and 29.5 times higher than that of pure ZnBi₂O₄ and Bi-Bi₂O₂CO₃, respectively. Moreover, O₂^- and h⁺ are the main active species in the photodegradation reaction. The improvement of the photocatalytic activity of the composites is attributed to the synergistic effect of ternary heterostructure and surface plasmon resonance (SPR), which promotes charge transfer and effectively inhibits the recombination of photogenerated carriers.

An activated carbon fiber supported Fe2O3@bismuth carbonate heterojunction for enhanced visible light degradation of emerging pharmaceutical pollutants

The developed Fe2O3@BC heterojunction photocatalyst supported over activated carbon fiber exhibited efficient photocatalytic activity for degradation of antipyrine under visible light irradiation.

Bi2O2CO3/TiO2 hybrid with 0D/1D nanostructure: design, synthesis and photocatalytic performance

A 0D/1D hybrid structure endows the catalyst with faster migration of photo-generated carriers and less recombination of electron/hole pairs.

Spatially Separating Redox Centers on Z-Scheme ZnIn2 S4 /BiVO4 Hierarchical Heterostructure for Highly Efficient Photocatalytic Hydrogen Evolution

Photocatalysis technology using solar energy for hydrogen (H₂ ) production still faces great challenges to design and synthesize highly efficient photocatalysts, which should realize the precise regulation of reactive sites, rapid migration of photoinduced carriers and strong visible light harvest. Here, a facile hierarchical Z-scheme system with ZnIn₂ S₄ /BiVO₄ heterojunction is proposed, which can precisely regulate redox centers at the ZnIn₂ S₄ /BiVO₄ hetero-interface by accelerating the separation and migration of photoinduced charges, and then enhance the oxidation and reduction ability of holes and electrons, respectively. Therefore, the ZnIn₂ S₄ /BiVO₄ heterojunction exhibits excellent photocatalytic performance with a much higher H₂ -evolution rate of 5.944 mmol g^-1 h^-1 , which is about five times higher than that of pure ZnIn₂ S₄ . Moreover, this heterojunction shows good stability and recycle ability, providing a promising photocatalyst for efficient H₂ production and a new strategy for the manufacture of remarkable photocatalytic materials.

The versatile biomedical applications of bismuth-based nanoparticles and composites: therapeutic, diagnostic, biosensing, and regenerative properties

Studies of nanosized forms of bismuth (Bi)-containing materials have recently expanded from optical, chemical, electronic, and engineering fields towards biomedicine, as a result of their safety, cost-effective fabrication processes, large surface area, high stability, and high versatility in terms of shape, size, and porosity. Bi, as a nontoxic and inexpensive diamagnetic heavy metal, has been used for the fabrication of various nanoparticles (NPs) with unique structural, physicochemical, and compositional features to combine various properties, such as a favourably high X-ray attenuation coefficient and near-infrared (NIR) absorbance, excellent light-to-heat conversion efficiency, and a long circulation half-life. These features have rendered bismuth-containing nanoparticles (BiNPs) with desirable performance for combined cancer therapy, photothermal and radiation therapy (RT), multimodal imaging, theranostics, drug delivery, biosensing, and tissue engineering. Bismuth oxyhalides (BiO_x, where X is Cl, Br or I) and bismuth chalcogenides, including bismuth oxide, bismuth sulfide, bismuth selenide, and bismuth telluride, have been heavily investigated for therapeutic purposes. The pharmacokinetics of these BiNPs can be easily improved via the facile modification of their surfaces with biocompatible polymers and proteins, resulting in enhanced colloidal stability, extended blood circulation, and reduced toxicity. Desirable antibacterial effects, bone regeneration potential, and tumor growth suppression under NIR laser radiation are the main biomedical research areas involving BiNPs that have opened up a new paradigm for their future clinical translation. This review emphasizes the synthesis and state-of-the-art progress related to the biomedical applications of BiNPs with different structures, sizes, and compositions. Furthermore, a comprehensive discussion focusing on challenges and future opportunities is presented.

Synthesis of α-Fe2O3/Bi2WO6 layered heterojunctions by in situ growth strategy with enhanced visible-light photocatalytic activity

Layered heterojunction structure with larger interface region for electron migration has attracted much attention in recent years. In this work, layered α-Fe₂O₃/Bi₂WO₆ heterojunctions with strong interlayer interaction were successfully synthesized through a facile in situ growth method. The strong interaction between α-Fe₂O₃ and Bi₂WO₆ had resulted in excellent photoelectrochemical performance. It was found that such structure promoted the interfacial photogenerated charges separation according to EIS and Tafel analysis, except for the expansion of visible-light absorption range. PL and TRPL characterizations further demonstrated that the recombination ratio of photoexcited electron-hole pairs was greatly reduced. The toluene photocatalytic degradation tests had showed that α-Fe₂O₃/Bi₂WO₆ composites exhibited much well activity under visible-light irradiation. Especially, 4%-Fe₂O₃/Bi₂WO₆ sample displayed the highest photocatalytic activity, which was around 3 and 4 times higher than that of pure Bi₂WO₆ and α-Fe₂O₃. Based on ESR results and free radical trapping experiments, hydroxyl radicals (·OH) and holes (h⁺) were regarded as the main active species. The establishment of Fe₂O₃/Bi₂WO₆ with layered heterojunctions could provide new insights into the construction of novel photocatalysts.

Synthesis of Bi-deficient monolayered Bi2WO6 nanosheets with enhanced photocatalytic activity under visible light irradiation

The strong protonated hydroxyl groups around Bi vacancies could efficiently promote the separation of photoexcited electron–hole pairs.

An inverse opal TiO2/g-C3N4 composite with a heterojunction for enhanced visible light-driven photocatalytic activity

An inverse opal TiO₂/g-C₃N₄ composite with excellent photogenerated electron–hole separation efficiency and enhanced visible light absorption efficiency was constructed.

Significantly Enhanced Aqueous Cr(VI) Removal Performance of Bi/ZnO Nanocomposites via Synergistic Effect of Adsorption and SPR-Promoted Visible Light Photoreduction

Bismuth nanoparticles (BiNPs) and Zinc Oxide photocatalysts (BiNPs/ZnO) with different Bi loadings were successfully prepared via a facile chemical method. Their morphology and structure were thoroughly characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), UV-Vis (Ultraviolet-Visible) diffuse reflectance spectroscopy (DRS), photoluminescence spectra (PL), and electrochemical impedance spectroscopy (EIS). The results showed that a modification of hexagonal wurtzite-phase ZnO nanoparticles with Bi is achievable with an intimate interfacial interaction within its composites. The performance of the photocatalytic Cr(VI) removal under visible light irradiation indicated that BiNPs/ZnO exhibited a superior removal performance to bare ZnO, Bi, and the counterpart sample prepared using a physical mixing method. The excellent performance of the BiNPs/ZnO photocatalysts could be ascribed to the synergistic effect between the considerable physical Cr (VI) adsorption and enhanced absorption intensity in the visible light region, due to the surface plasmon resonance (SPR) as well as the effective transfer and separation of the photogenerated charge carriers at the interface.

Deep Oxidation of NO by a Hybrid System of Plasma-N-Type Semiconductors: High-Energy Electron-Activated "Pseudo Photocatalysis" Behavior

A "pseudo photocatalysis" process, being initiated between plasma and N-type semiconductors in the absence of light, was investigated for NO removal for the first time via dynamic probing of reaction processes by FT-IR spectra. It was demonstrated that N-type semiconductor catalysts could be activated to produce electron-hole (e^--h⁺) pairs by the collision of high-energy electrons (e*) from plasma. Due to the synergy of plasma and N-type semiconductors, major changes were noted in the conversion pathways and products. NO can be directly converted to NO₂^- and NO₃^- instead of toxic NO₂, owing to the formation of O₂^- and ·OH present in catalysts. New species like O₃ or ·O may be generated from the interaction between catalyst-induced species and radicals in plasma at a higher SIE, leading to deep oxidation of existing NO₂ to N₂O₅. Experiments with added trapping agents confirmed the contribution of e^- and h⁺ from catalysts. A series of possible reactions were proposed to describe reaction pathways and the mechanism of this synergistic effect. We established a novel system and realized an e*-activated "pseudo photocatalysis" behavior, facilitating the deep degradation of NO. We expect that this new strategy would provide a new idea for in-depth analysis of plasma-activated catalysis phenomenon.

Nanobismuth: Fabrication, Optical, and Plasmonic Properties—Emerging Applications

Along the twentieth century, the electronic properties of bismuth have been widely studied, especially in relation with its magnetoresistive and thermoelectric responses. In this context, a particular emphasis has been made on electronic confinement effects in bismuth nanostructures (or nanobismuth). In the recent years, the optical properties of bismuth nanostructures are focusing a growing interest. An increasing number of reports point at the potential of such nanostructures to support plentiful optical resonances over an ultrabroad spectral range: “interband plasmonic” resonances in the ultraviolet, visible, and near-infrared; dielectric Mie resonances in mid- and far-infrared; and conventional free-carrier plasmonic resonances in the far-infrared and terahertz. With the aim to provide a comprehensive basis for exploiting the full optical potential of bismuth nanostructures, we review the current progress in their controlled fabrication, the trends reported (from theoretical calculations and experimental observations) for their optical and plasmonic response, and their emerging applications, including photocatalysis and switchable metamaterials.

Bi12O17Cl2/(BiO)2CO3 Nanocomposite Materials for Pollutant Adsorption and Degradation: Modulation of the Functional Properties by Composition Tailoring

Bi₁₂O₁₇Cl₂/(BiO)₂CO₃ nanocomposite materials were studied as bifunctional systems for depuration of wastewater. They are able to efficiently adsorb and decompose rhodamine B (RhB) and methyl orange (MO), used as model pollutants. Bi₁₂O₁₇Cl₂/(BiO)₂CO₃ nanocomposites were synthesized at room temperature and ambient pressure by means of controlled hydrolysis of BiCl₃ in the presence of a surfactant (Brij 76). Cold treatments of the pristine samples with UV light or thermal annealing at different temperatures (370-500 °C) and atmospheres (air, Ar/30% O₂) were adopted to modulate the relative amounts of Bi₁₂O₁₇Cl₂/(BiO)₂CO₃ and hence the morphology, surface area, ζ-potential, optical absorption in the visible range, and the adsorption/degradation of pollutants. The best performance was achieved by (BiO)₂CO₃-rich samples, which adsorbed 80% of MO and decomposed the remaining 20% by visible light photocatalysis. Irrespective of the dye, all of the samples were able to almost complete the adsorption step within 10 min contact time. Bi₁₂O₁₇Cl₂-rich composite materials displayed a lower adsorption ability, but thanks to the stronger absorption in the visible range they behaved as more effective photocatalysts. The obtained results evidenced the ability of the employed strategy to modulate sample properties in a wide range, thus pointing out the effectiveness of this approach for the synthesis of multifunctional inorganic materials for environmental remediation.

Br-Doped Bi2O2CO3 exposed (001) crystal facets with enhanced photocatalytic activity

Br-Doped Bi₂O₂CO₃ exposed (001) facets were synthesized using CTAB as a surfactant and dopant. The highly enhanced photocatalytic performance of Br-doped Bi₂O₂CO₃ is attributed to the synergistic effects of the doping of Br⁻ and the active exposed (001) crystal facet.

In-Situ Hydrothermal Synthesis of Bi-Bi2O2CO3 Heterojunction Photocatalyst with Enhanced Visible Light Photocatalytic Activity

Bismuth containing nanomaterials recently received increasing attention with respect to environmental applications because of their low cost, high stability and nontoxicity. In this work, Bi-Bi₂O₂CO₃ heterojunctions were fabricated by in-situ decoration of Bi nanoparticles on Bi₂O₂CO₃ nanosheets via a simple hydrothermal synthesis approach. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM) were used to confirm the morphology of the nanosheet-like heterostructure of the Bi-Bi₂O₂CO₃ composite. Detailed ultrafast electronic spectroscopy reveals that the in-situ decoration of Bi nanoparticles on Bi₂O₂CO₃ nanosheets exhibit a dramatically enhanced electron-hole pair separation rate, which results in an extraordinarily high photocatalytic activity for the degradation of a model organic dye, methylene blue (MB) under visible light illumination. Cycling experiments revealed a good photochemical stability of the Bi-Bi₂O₂CO₃ heterojunction under repeated irradiation. Photocurrent measurements further indicated that the heterojunction incredibly enhanced the charge generation and suppressed the charge recombination of photogenerated electron-hole pairs.

Hierarchical photocatalysts

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

Controllable self-assembly of a novel Bi2MoO6-based hybrid photocatalyst: excellent photocatalytic activity under UV, visible and near-infrared irradiation

Herein, using a simple one-step method, a Bi₂MoO₆-based photocatalyst with novel ultrathin nanohollow structure and simultaneous sub-10 nm Bi nanoparticles and sub-1 nm graphitic nitrogen-doped carbon nanodots (NCDs) modification were successfully obtained.

Green synthesis of copper nanoparticles for the efficient removal (degradation) of dye from aqueous phase

The present work reports the utilization of a common household waste material (fish scales of Labeo rohita) for the synthesis of copper nanoparticles. The method so developed was found to be green, environment-friendly, and economic. The fish scale extracts were acting as a stabilizing and reducing agents. This method avoids the use of external reducing and stabilizing agents, templates, and solvents. The compositional abundance of gelatin may be envisaged for the effective reductive as well as stabilizing potency. The mechanisms for the formation of nanoparticles have also been presented. The synthesized copper nanoparticles formed were predominantly spherical in nature with an average size of nanoparticles in the range of 25-37 nm. The copper nanoparticles showed characteristic Bragg's reflection planes of fcc which was supported by both selected area electron diffraction and X-ray diffraction pattern and showed surface plasmon resonance at 580 nm. Moreover, the energy dispersive spectroscopy pattern also revealed the presence of only elemental copper in the copper nanoparticles. The prepared nanoparticles were used for the remediation of a carcinogenic and noxious textile dye, Methylene blue, from aqueous solution. Approximately, 96 % degradation of Methylene blue dye was observed within 135 min using copper nanoparticles. The probable mechanism for the degradation of the dye has been presented, and the degraded intermediates have been identified using the liquid chromatography-mass spectroscopy technique. The high efficiency of nanoparticles as photocatalysts has opened a promising application for the removal of hazardous dye from industrial effluents contributing indirectly to environmental cleanup process.

Photo-synergistic promoted in situ generation of Bi0–BiSbO4 nanostructures as an efficient catalyst for nitrobenzene reduction

This work reports on the construction of Bi⁰–BiSbO₄ nanostructures to show photo-synergistic and efficient catalytic activity toward nitrobenzenes reduction.