Review on synthetic approaches and PEC activity performance of bismuth binary and mixed-anion compounds for potential applications in marine engineering

Photoelectrochemical (PEC) technology in marine engineering holds significant importance due to its potential to address various challenges in the marine environment. Currently, PEC-type applications in marine engineering offer numerous benefits, including sustainable energy generation, water desalination and treatment, photodetection, and communication. Finding novel efficient photoresponse semiconductors is of great significance for the development of PEC-type techniques in the marine space. Bismuth-based semiconductor materials possess suitable and tunable bandgap structures, high carrier mobility, low toxicity, and strong oxidation capacity, which gives them great potential for PEC-type applications in marine engineering. In this paper, the structure and properties of bismuth binary and mixed-anion semiconductors have been reviewed. Meanwhile, the recent progress and synthetic approaches were discussed from the point of view of the application prospects. Finally, the issues and challenges of bismuth binary and mixed-anion semiconductors in PEC-type photodetection and hydrogen generation are analyzed. Thus, this perspective will not only stimulate the further investigation and application of bismuth binary and mixed-anion semiconductors in marine engineering but also help related practitioners understand the recent progress and potential applications of bismuth binary and mixed-anion compounds.

Potential application of bismuth oxyiodide (BiOI) when it meets light

Bismuth oxyiodide (BiOI) is a kind of typical two-dimensional (2D) material that has been increasingly developed alongside other 2D materials such as graphene, MXenes, and transition-metal dichalcogenide. However, its potential applications have not been widely whispered compared to those of other 2D materials. Using its distinctive properties, BiOI can be used for various applications, especially when it meets sunlight and other light-related electromagnetic waves. In this present review, we discuss the developments of BiOI and challenges in the applications for photodetector and light-assisted sensors, photovoltaic devices, optoelectronic logic devices, as well as photocatalysts. We start the discussion with a basic understanding and development of BiOI, crystal structure, and its properties. The synthesis and further development, such as green synthesis and its challenges in the synthesis-suited industry, as well as device integration, are also explained together with a plausible strategy to enhance the feasibility of BiOI for those various applications. We believe that the provided discussion and perspectives will not only promote BiOI to be one of the highly considered 2D materials but can also assist recent graduates in any materials science discipline and inform the senior scientists and industrial-based stakeholders of the latest advances in bismuth oxide and mixed-anion compounds.

Visible-Light-Active Iodide-Doped BiOBr Coatings for Sustainable Infrastructure

The search for efficient materials for sustainable infrastructure is an urgent challenge toward potential negative emission technologies and the global environmental crisis. Pleasant, efficient sunlight-activated coatings for applications in self-cleaning windows are sought in the glass industry, particularly those produced from scalable technologies. The current work presents visible-light-active iodide-doped BiOBr thin films fabricated using aerosol-assisted chemical vapor deposition. The impact of dopant concentration on the structural, morphological, and optical properties was studied systematically. The photocatalytic properties of the parent materials and as-deposited doped films were evaluated using the smart ink test. An optimized material was identified as containing 2.7 atom % iodide dopant. Insight into the photocatalytic behavior of these coatings was gathered from photoluminescence and photoelectrochemical studies. The optimum photocatalytic performance could be explained from a balance between photon absorption, charge generation, carrier separation, and charge transport properties under 450 nm irradiation. This optimized iodide-doped BiOBr coating is an excellent candidate for the photodegradation of volatile organic pollutants, with potential applications in self-cleaning windows and other surfaces.

Comparative Study of Bi2 O3 , MgO and ZrO2 Nanomaterials designed by Polymer Sacrificial Method for Amoxicillin delivery and Bone Regeneration: In-Vitro Studies.. [DOI: 10.21203/rs.3.rs-3146890/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Hard tissue scientists face many difficulties, including persistent osteomyelitis and diseased bone abnormalities. Inorganic mesoporous nanomaterials are excellent candidates for the adsorption and loading of bioactive medicinal substances because to their chemical-physical characteristics. Recently, zirconium oxide, magnesium oxide and bismuth oxide nanoparticles are of great surface area and biocompatibility, and they have been described as a new drug delivery carrier. In this study, amoxicillin antibiotic was loaded into the prepared mesoporous nanomaterials (ZrO2, MgO and Bi2O3) to form a local antibiotic delivery system. The prepared mesoporous nanomaterials were investigated by XRD, FTIR, TEM, zeta potential and BET surface area measurements. Amoxicillin antibiotic was released from the prepared mesoporous nanomaterials in PBS. The effectiveness of the antibacterial study against several gram-positive and gram-negative bacterial strains was assessed. The cytotoxicity study of the human osteoblast-like cells (MG-63) was tested for all prepared mesoporous nanomaterials utilizing MTT assay. ZrO2 demonstrated particle diameters in the range of (5.26– 11.47nm), MgO was (70–80nm) and Bi2O3 was (9.79– 13.7nm). The greater surface area was confirmed for Bi2O3 sample (3.99 m2g− 1) by BET surface area. Amoxicillin loaded mesoporous nano powders exhibited impressive antibacterial and antifungal activities. MgO and Bi2O3 mesoporous nanoparticles exhibited better antimicrobial activities compared to ZrO2 sample. The proliferation for all samples gave good results especially for MgO and Bi2O3. As a result, the produced mesoporous nanomaterials have a significant potential for use as medicine delivery systems for bone regeneration and for enhancing the properties of other products in medical applications.

Near-Ultraviolet Light-Driven Photocathodic Activity for (001)-Oriented BiOCl Thin Films Synthesized by Mist Chemical Vapor Deposition

Semitransparent and homogeneous bismuth oxychloride (BiOCl) thin films with (001) preferred orientation were synthesized on polycrystalline Sn:In₂O₃-glass substrates by mist chemical vapor deposition. The films showed photocathodic activity even under near-ultraviolet light within the band gap due to the in-gap states induced by oxygen vacancies. Higher synthesis temperatures resulted in a significant increase of photocurrent density under ultraviolet light. While the longer lifetime of photocarriers led to an increase of internal quantum efficiency, the larger band-edge absorption significantly contributed to the higher external quantum efficiency.

Synergistic photocatalytic effect of BiOBr-BiOI heterojunctions due to appropriate layer stacking

The increasing interest in acquiring efficient visible-light active photocatalytic materials has led to the formation of heterojunctions with different combinations of semiconductors. Despite the fact that increasingly more complex structures are proposed, there are still many unclear factors affecting their performance and limiting their prompt implementation. In this work, we used the spray pyrolysis technique to deposit individual visible light-active BiOBr and BiOI films and formed the heterojunctions BiOBr-BiOI and BiOI-BiOBr to determine the effect of the stacking order of semiconductors. These materials were widely characterized; their structural, optical, (photo)electrochemical, and photocatalytic properties were evaluated, revealing that the configuration BiOI-BiOBr boosted the photocatalytic indigo carmine dye removal under simulated sunlight irradiation, but the opposite layout quenched it. The high efficiency is attributed to a better use of the incident radiation and the effective migration of the photogenerated carriers. BiOBr - with a wider band gap and a less negative conduction band with respect to BiOI - provides its good attributes to the heterostructure, such as high stability and low recombination rates, when it is at the surface. We demonstrated that in thin-film heterostructures, the order in which the layers are stacked becomes decisive for the photocatalytic performance and that the energy band gap and the relative band positions of both semiconductors are the principal features that govern the photocatalytic mechanism. These findings provide a key to designing more efficient photocatalysts without several unsuccessful trials.

Oxygen vacancy-rich hierarchical BiOBr hollow microspheres with dramatic CO2 photoreduction activity

Conversion of carbon dioxide into useful chemicals has attracted great attention. However, the significant bottlenecks facing in the field are the poor conversion efficiency of CO₂ and low selectivity of products. Herein, hierarchical BiOBr hollow microspheres are fabricated by a solvothermal method using ethylene glycol (EG) as solvent in presence of polyvinyl pyrrolidone (PVP). The hollow BiOBr microspheres prepared at 120 °C exhibit the best performance for CO₂ photoreduction. The evolution rates of product CO and CH₄ are up to 88.1 µmol g^-1h^-1 and 5.8 µmol g^-1h^-1, which are 8.8 times and 5.8 times higher than that of plate-like BiOBr respectively. The hollow microspheres possess larger specific area and generate multiple reflections of light in the cavity, thus enhancing the utilization efficiency of light. The modulated electronic structure by oxygen vacancy (OVs) is beneficial to the transfer of photogenerated electrons and holes. Especially, the enriched charge density of BiOBr by OVs is conductive to the adsorption and activation of CO₂, which could lower the overall activation energy barrier of CO₂ photoreduction_. In summary, the synergistic effect of the hollow structure with OVs plays a vital role in boosting the photoreduction of CO₂ for BiOBr. This work provides a new opportunity for designing the high efficiency catalyst by morphology engineering with defects at the atomic level for CO₂ photoreduction.

Room temperature synthesis of BiOBr1-x I x thin films with tunable structure and conductivity type for enhanced photoelectric performance

The surface states of semiconductors determine the semiconductor type. Although BiOCI, BiOBr and BiOI all belong to the bismuth oxyhalide semiconductor family and have similar crystal structures and electronic structures, they exhibit different conductivity types due to their respective surface states. In this paper, a modified successive ionic layer adsorption and reaction (SILAR) method was developed to fabricate I-doped BiOBr_1-x I _x nanosheet array films on FTO substrates at room temperature for the first time. Interestingly, the properties of p-type BiOBr were changed by doping an appropriate amount of iodine into a BiOBr film to form an n-type BiOBr_1-x I _x thin film. The I-doped BiOBr_1-x I _x (x = 0.2, 0.4, 0.5) nanosheet arrays had a perfect single-crystal structure, and the dominant growth plane was (110). A higher doping amount of I led to a darker colour of the BiOBr_1-x I _x film and a redshift of the absorption wavelength; consequently, the bandgap value changed from 2.80 eV to 1.85 eV. The highest short-circuit current and open-circuit voltage of the solar cell based on BiOBr_0.5I_0.5 film could reach 1.73 mA cm^-2 and 0.55 V, which was considered to be attributed to the effective light absorbance, long photogenerated charge lifetime and sufficient charge separation in the BiOBr_0.5I_0.5 film.

Epitaxial growth of bismuth oxyhalide thin films using mist CVD at atmospheric pressure

We report the epitaxial growth of bismuth oxyhalide BiOX (X = Cl, Br, and I) thin films using mist chemical vapour deposition at atmospheric pressure. The thin films grown under optimum conditions possessed atomically flat surfaces and high crystallinity, where the lattice constants of BiOX were controlled by epitaxial strain.

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.

A novel zero valent metal bismuth for bromate removal: direct and ultraviolet enhanced reduction

Bromate (BrO₃⁻) is a carcinogenic and genotoxic by-product of the ozone disinfection process. In this study, a new zero-valent metal, bismuth, was used to reduce bromate. Bismuth samples were prepared by a solvothermal method and characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The morphology of the bismuth powder was microspheres assembled with dense nanosheets. The kinetics of the direct bromate reduction by bismuth accorded with the pseudo-first-order kinetics model. The rate coefficients of the initial bromate concentration of 1.00 mg L⁻¹, 2.50 mg L⁻¹, 5.00 mg L⁻¹ were identically close to 0.08 min⁻¹. For 0.20 mg L⁻¹, a reaction rate coefficient near 0.10 min⁻¹ was obtained. The reducing products of bromate included bromide ions (Br⁻) and bismuth oxybromides. The bromate removal efficiency was enhanced remarkably in the presence of ultraviolet (UV) light, and the corresponding kinetic coefficient was 4 times higher than that of direct reduction. The mechanism of ultraviolet enhancement was analyzed by diffuse reflectance spectroscopy (DRS), the density functional theory (DFT) calculation, open circuit potential (OCP) analysis, photocurrent measurement and linear sweep voltammetry (LSV). Besides, the influence of dissolved oxygen (DO) on bromate reduction efficiency and the sustainability of the as-prepared sample were investigated. DO inhibited the reduction rate obviously, but showed a slight effect on the formation of bromide ions. In the long-term periodic experiments, the kinetic coefficient decay occurred in both direct (without UV irradiation) and ultraviolet assisted bromate reduction. However, the kinetic coefficient of UV-assisted reduction (0.115 min⁻¹) was about 2 times higher than that of the direct reduction in the last cycle of periodic experiments. In conclusion, the novel bromate reduction strategy based on the zero-valent bismuth metal material has been proved efficient and sustainable, which contributes to the development of drinking water treatment technologies.

The inert metal bismuth is proved to be effective for the direct reduction of bromate while the reducing process is dramatically promoted under the presence of ultraviolet light, since bismuth is a typical semi-metal.

Manganese ions conjugated on layered bismuth oxyhalides for high-performance pseudocapacitors and efficient oxygen evolution catalysts

The synthesized Mn-BiOX (X = Cl, I and Br).