Search Results (19)

A novel photoelectrochemical (PEC) biosensor was proposed by preparing Au NP/MXene–BiOCl Moiré superlattice nanosheets as the probes. Upon irradiation with visible light, the probe exhibited excellent electrical conductivity as well as high photoelectric conversion efficiency. Benefitting from the excellent PEC property of the hybrid probe, sensitive and accurate detection of protein kinase activity was demonstrated with a limit of detection of 0.0029 U mL⁻¹. This study verifies the great PEC potential of MXene hybrid nanomaterials. Full article

In this study, biochar-loaded E³⁺:BiOCl (C/3E³⁺:BiOCl) was synthesized with varying levels of E³⁺ doping using a one-step solvothermal method and used for tetracycline hydrochloride (TC-HCl) degradation. Their structure, shape and morphology were not only characterized by power X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) but also by UV-vis diffuse reflectance spectra and upconversion (UC). The results indicated a significant enhancement in the photocatalytic activity of the catalyst following the introduction of Er³⁺. The composite material C/3E³⁺:BiOCl, with a doping concentration of 3 mol%, demonstrated the highest photocatalytic activity, achieving an impressive visible light degradation efficiency of 89.2% for TC HCl within 90 min. This marks an increase of 33.5% compared to the BiOCl monomer and 17.4% compared to C/BiOCl. Additionally, when exposed to light with wavelengths exceeding 600 nm, C/3E³⁺:BiOCl maintained a photodegradation efficiency of 44.3%, while BiOCl and C/BiOCl showed no photocatalytic activity under the same conditions. This finding highlights the effectiveness of BiOCl as a doping matrix, which enhances the photocatalytic performance of BiOCl through the upconversion effect of E³⁺ and the electron transfer mechanisms associated with biochar. Full article

Polyurethane/silk protein–bismuth halide oxide composite films were fabricated using a blending-wet phase transformationin situsynthesis method. The crystal structure, micromorphology, and optical properties were conducted using XRD, SEM, and UV-Vis DRS characterize techniques. The results indicated that loaded silk protein enhanced the hydrophilicity and pore structure of the polyurethane composite films. The active species BiOX were observed to grow as nanosheets with high dispersion on the internal skeleton and silk protein surface of the polyurethane–silk protein film. The photocatalytic efficiency of BiOX/PU-SF composite films was assessed through the degradation of Rhodamine B under visible light irradiation. Among the tested films, the BiOBr/PU-SF composite exhibited the highest removal rate of RhB at 98.9%, surpassing the removal rates of 93.7% for the BiOCl/PU-SF composite and 85.6% for the BiOI/PU-SF composite. Furthermore, an active species capture test indicated that superoxide radical (•O₂⁻) and hole (h⁺) species played a predominant role in the photodegradation process. Full article

In recent years, oxygen vacancy (V_O) engineering has become a research hotspot in the field of photocatalysis. Herein, an efficient GQDs/BiOCl-V_O 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-V_O sample exhibited improved efficiency for RhB degradation under visible-light irradiation. A 2 wt% GQDs/BiOCl-V_O 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. Full article

Doping engineering of metallic elements is of significant importance in photocatalysis, especially in the transition element range where metals possess empty ‘d’ orbitals that readily absorb electrons and increase carrier concentration. The doping of Mn ions produces dipole interactions that change the local structure of BiOCl, thus increasing the specific surface area of BiOCl and the number of mesoporous distributions, and providing a broader platform and richer surface active sites for catalytic reactions. The combination of Mn doping and metal Bi reduces the forbidden bandwidth of BiOCl, thereby increasing the absorption in the light region and strengthening the photocatalytic ability of BiOCl. The degradation of norfloxacin by Bi/Mn-doped BiOCl can reach 86.5% within 10 min. The synergistic effect of Mn doping and Bi metal can change the internal energy level and increase light absorption simultaneously. The photocatalytic system created by such a dual-technology combination has promising applications in environmental remediation. Full article

Semiconductor photocatalysts are essential materials in the field of environmental remediation. Various photocatalysts have been developed to solve the contamination problem of norfloxacin in water pollution. Among them, a crucial ternary photocatalyst, BiOCl, has attracted extensive attention due to its unique layered structure. In this work, high-crystallinity BiOCl nanosheets were prepared using a one-step hydrothermal method. The obtained BiOCl nanosheets showed good photocatalytic degradation performance, and the degradation rate of highly toxic norfloxacin using BiOCl reached 84% within 180 min. The internal structure and surface chemical state of BiOCl were analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman, Fourier transform infrared spectroscopy (FTIR), UV–visible diffuse reflectance (UV-vis), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectra (XPS), and photoelectric techniques. The higher crystallinity of BiOCl closely aligned molecules with each other, which improved the separation efficiency of photogenerated charges and showed high degradation efficiency for norfloxacin antibiotics. Furthermore, the obtained BiOCl nanosheets possess decent photocatalytic stability and recyclability. Full article

Fe-BiOCl-V_o nanosheets with electron-capture centers of doped Fe and surface oxygen vacancies (V_o) for enhanced photocatalytic-Fenton performances were conducted. Compared with pristine BiOCl nanosheets, the band gap of the resulting Fe-BiOCl-V_o nanosheets was narrowed, and defective bands were introduced due to the Fe doping and V_o. Furthermore, the integrated electron trapping effect of V_o and doped Fe can efficiently drive charge transfer and separation. As a result, the photocatalytic-Fenton performances of phenol over Fe-BiOCl-V_o nanosheets were enhanced. The photocatalytic-Fenton performances of Fe-BiOCl-V_o nanosheets were enhanced two-fold and four-fold, respectively, as compared with the photocatalytic performances of Fe-BiOCl-V_o and pristine BiOCl nanosheets. During the photocatalytic-Fenton process, the multiple reactive species referring holes (h⁺), superoxide radicals (●O₂⁻), and hydroxyl radicals (●OH) induced by the efficiently separated charge carriers and Fenton reaction played synergetic roles in phenol degradation and mineralization. This work provides a sophisticated structure design of catalysts for efficient charge transfer and separation, promoting photocatalytic-Fenton performance. Full article

BiOIO₃ exhibits excellent oxidation capacity in the photocatalytic degradation of contaminants thanks to its unique polarized electric and internal electrostatic field. However, the synthetic method of BiOIO₃ nanomaterials is mainly focused on hydrothermal technology, owing to its high energy consumption and time-consuming nature. In this work, a BiOIO₃ nanosheet was prepared by a simple solid-state chemical reaction, which was identified by XRD, EDS, XPS, and HRTEM. Benefiting from the strong oxidation ability of the valence band maximum, the distinctive layer structure, and the promoted generation of ·O₂⁻, the BiOIO₃ nanosheet exhibits excellent photo-degradation activity for methyl orange (MO) and its apparent rate constant is 0.2179 min⁻¹, which is about 3.02, 8.60, and 10.26 times higher than that of P25, BiOCl, and Bi₂O₂CO₃, respectively. Interestingly, the BiOIO₃ nanosheet also has good photocatalytic degradation performance for phenolic compounds; in particular, the degradation rate of BPA can reach 96.5% after 16 min, mainly due to hydroxylation reaction. Full article

Photocatalytic degradation has gained much attention as a means of reducing water contamination as, with increasing industrialization and population growth, water pollution is a menace to both individuals and the environment. In this respect, metal oxide photocatalysts demonstrate effectiveness due to their excellent properties, such as their narrow band gap and low recombination rate of charge carriers. Here, various weight ratios of BiOCl/PANI composites have been synthesized by the simple wet chemical method. The crystallinity, oxidation state and surface chemical composition of the elements were analyzed by XRD and XPS techniques. FESEM and HRTEM images verified the formation of BiOCl nanosheets, covered well with PANI nanofibers, while EDX spectra revealed the uniform distribution of elements. The high surface area of the photocatalyst with a mesoporous nature was revealed by BET analysis. Low recombination rate and narrow band gap, suitable for photocatalysis, were confirmed by PL and UV–DRS spectroscopy. The photocatalytic performance of the photocatalyst was tested for the photodegradation of rhodamine-B (Rh-B) and tetracycline (TC) under natural sunlight irradiation. Kinetic results demonstrated that the 15% BiOCl/PANI hybrid exhibits excellent photocatalytic activity, degrading 97% of Rh-B and 77% of TC with a high rate constant (for Rh-B 0.0236 min⁻¹ and for TC 0.0106 min⁻¹). Trapping experiments highlighted that O₂^•− radicals play a vital role in the photodegradation mechanism. The reusability studies confirmed the good stability of the catalyst for the degradation of Rh-B (~85%) after five sequential runs. Considering its superior properties and ease of preparation, the synthesized photocatalyst can be used for ecological remediation. Full article

Photocatalytic degradation of organic pollutants in wastewater is recognized as a promising technology. However, photocatalyst Bi₂O₃ responds to visible light and suffers from low quantum yield. In this study, the α-Bi₂O₃ was synthetized and used for removing Cl⁻ in acidic solutions to transform BiOCl. A heterostructured α-Bi₂O₃/BiOCl nanosheet can be fabricated by coupling Bi₂O₃ (narrow band gap) with layered BiOCl (rapid photoelectron transmission). During the degradation of Rhodamine B (RhB), the Bi₂O₃/BiOCl composite material presented excellent photocatalytic activity. Under visible light irradiation for 60 min, the Bi₂O₃/BiOCl photocatalyst delivered a superior removal rate of 99.9%, which was much higher than pristine Bi₂O₃ (36.0%) and BiOCl (74.4%). Radical quenching experiments and electron spin resonance spectra further confirmed the dominant effect of electron holes h⁺ and superoxide radical anions ·O₂⁻ for the photodegradation process. This work develops a green strategy to synthesize a high-performance photocatalyst for organic dye degradation. Full article

Oxygen vacancy manipulation and hierarchical morphology construction in oxygen-containing semiconductors have been demonstrated to be effective strategies for developing high efficiency photocatalysts. In most studies of bismuth-based photocatalysts, hierarchical morphology and crystal defects are achieved separately, so the catalysts are not able to benefit from both features. Herein, using boiling ethylene glycol as the treatment solution, we developed an etching-recrystallization method for the fabrication of 3D hierarchical defective BiOCl at ambient pressure. The target hierarchical 3D-BiOCl is composed of self-assembled BiOCl nanosheets, which exhibit a hexagonal prism-like morphology on a micron scale, while simultaneously containing numerous oxygen vacancies within the crystal structure. Consequently, the target catalyst was endowed with a higher specific surface area, greater light harvesting capability, as well as more efficient separation and transfer of photo-excited charges than pristine BiOCl. As a result, 3D-BiOCl presented an impressive photocatalytic activity for the degradation of tetracycline hydrochloride in both visible light and natural white light emitting diode (LED) irradiation. Moreover, an extraordinary recycling property was demonstrated for the target photocatalyst thanks to its hierarchical structure. This study outlines a simple and energy-efficient approach for producing high-performance hierarchically defective BiOCl, which may also open up new possibilities for the morphological and crystal structural defect regulation of other Bi-based photocatalysts. Full article

There are many reports on g-C₃N₄ nanosheet and BiOCl nanosheet, but few studies on other morphologies of g-C₃N₄ and BiOCl. Herein, a g-C₃N₄ nanoball/BiOCl nanotube heterojunction prepared by a simple one-step acetonitrile solvothermal method is reported. The XRD results prove that the g-C₃N₄/BiOCl composites can be prepared in one step. SEM results revealed that the g-C₃N₄ was spherical and the BiOCl was tubular. The HRTEM results indicate that g-C₃N₄ has an amorphous structure and that the (100) crystal plane of BiOCl borders the g-C₃N₄. Spherical g-C₃N₄ has a narrow band gap (approximately 1.94 eV), and the band gap of g-C₃N₄/BiOCl after modification was also narrow. When the BiOCl accounted for 30% of the g-C₃N₄/BiOCl by mass, the quasi-primary reaction rate constant of RhB degradation was 45 times that of g-C₃N₄. This successful preparation method for optimizing g-C₃N₄ involving simple one-step template-free synthesis may be adopted for the preparation of diverse-shapes and high-performance nanomaterials in the future. Full article

Crystal facet engineering and nonmetal doping are regarded as effective strategies for improving the separation of charge carriers and photocatalytic activity of semiconductor photocatalysts. In this paper, we developed a facial method for fabricating oxygen-deficient Br-doped BiOCl nanosheets with dominating {001} facets through a traditional hydrothermal reaction and explored the impact of the Br doping and specific facets on carrier separation and photocatalytic performance. The morphologies, structures, and optical and photocatalytic properties of the obtained products were characterized systematically. The BiOCl samples prepared by the hydrothermal reaction exhibited square-like shapes with dominating {001} facets. Photodeposition results indicated that photoinduced electrons preferred to transfer to {001} facets because of the strong internal static electric fields in BiOCl nanosheets with dominating {001} facets. Br doping not only contributed to the formation of impurity energy levels that could promote light absorption but introduced a large number of surface oxygen vacancies (V_O) in BiOCl photocatalysts, which was beneficial for photocatalytic performance. Moreover, the photocatalytic activities of these products under visible light were tested by degradation of rhodamine B (RhB). Because of the synergistic effect of the dominating {001} facets, Br doping, and rich V_O, oxygen-deficient Br-doped BiOCl nanosheets exhibited improved carrier separation, visible light absorption, and photocatalytic efficiency. Full article

Semiconductor photocatalysis is considered to be a promising technique to completely eliminate the organic pollutants in wastewater. Recently, S-scheme heterojunction photocatalysts have received much attention due to their high solar efficiency, superior transfer efficiency of charge carriers, and strong redox ability. Herein, we fabricated an S-scheme heterostructure BiOCl/MoSe₂ by loading MoSe₂ nanosheets on the surface of BiOCl microcrystals, using a solvothermal method. The microstructures, light absorption, and photoelectrochemical performances of the samples were characterized by the means of SEM, TEM, XRD, transient photocurrents, electrochemical impedance, and photoluminescence (PL) spectra. The photocatalytic activities of BiOCl, MoSe₂, and the BiOCl/MoSe₂ samples with different MoSe₂ contents were evaluated by the degradation of methyl orange (MO) and antibiotic sulfadiazine (SD) under simulated sunlight irradiation. It was found that BiOCl/MoSe₂ displayed an evidently enhanced photocatalytic activity compared to single BiOCl and MoSe₂, and 30 wt.% was an optimal loading amount for obtaining the highest photocatalytic activity. On the basis of radical trapping experiments and energy level analyses, it was deduced that BiOCl/MoSe₂ follows an S-scheme charge transfer pathway and •O₂⁻, •OH, and h⁺ all take part in the degradation of organic pollutants. Full article

The novel 2D/2D S-scheme heterostructure of BiOCl nanosheets coupled with CaIn₂S₄ nanosheets (CaIn₂S₄/BiOCl-SOVs), which contains surface oxygen vacancies (SOVs), has been successfully prepared by high-temperature calcination combined with a solvothermal synthetic strategy. Under visible-light irradiation, the apparent rate constant (K_app/mim⁻¹) for phenol degradation on the 1 wt% CaIn₂S₄/BiOCl-SOVs photocatalyst is about 32.8 times higher than that of pure BiOCl. The superior performance was attributed to the synergistic effect between the SOVs, CaIn₂S₄, and BiOCl, which can effectively narrow the bandgap and accelerate the interfacial charge separation of CaIn₂S₄/BiOCl-SOVs heterojunctions. Subsequently, it significantly promotes the generation of superoxide radicals (O₂⁻), hydroxyl radicals, and h⁺, which participate in the photodegradation process of phenol. The catalyst still maintained a relatively high activity after repeated tests as a demonstration of its photostability. This work successfully proposed an efficient method to design a new 2D/2D S-scheme heterostructure with SOVs as possible photocatalysts in the field of environmental remediation. Full article