Bi2MoO6 Nanoparticles Research Articles

Fe-doped MOF(Ti)/Bi2MoO6 heterostructure for boosting oxidation/reduction activities under visible light

Constructing of metal-organic framework (MOF) based heterostructures is a feasible strategy to enhance the photocatalytic activities of MOFs in wastewater treatments. Herein, a novel Fe-doped NH2-MIL-125(Ti)/Bi2MoO6 heterostructure (Fe-MOF(Ti)/BMO) was designed and prepared by modifying Bi2MoO6 nanoparticles on the Fe-MOF(Ti) surface by a simple solvothermal method. As expected, the Fe-MOF(Ti)/BMO composites displayed more conspicuous photocatalytic properties toward the Cr(VI) reduction and methyl orange (MO) degradation compared to the Fe-MOF(Ti) under visible light. Especially, the optimal Fe-MOF(Ti)/BMO0.4 exhibited the highest photocatalytic activities for the Cr(VI) reduction and MO degradation, around 1.2 and 1.4 times as high as those of the Fe-MOF(Ti), while the Cr(VI) removal efficiency was still kept above 96.5 % after 5 cycles, superior to that Fe-MOF(Ti) (95.1 %). The enhanced photocatalytic activity and stability of the Fe-MOF(Ti)/BMO0.4 were owed to the well-dispersed Bi2MoO6 nanoparticles, high interfacial charge transfer and strong interfacial contact between the two components induced by the formation of type II heterostructure. Ultimately, the possible enhanced photocatalytic mechanism over the Fe-MOF(Ti)/BMO heterostructure was also proposed. This work demonstrated the MOF-based heterostructure materials have a great potentiality for semiconductor photocatalysis in environmental remediations.

Achieving high-efficiency electromagnetic wave absorption performance in a 3-layer hierarchical porous magneto-dielectric nanocomposite

Hierarchical porous structures along with micro- and nanoparticles of magneto-dielectric components in sandwich structure design have superior potential applications in the field of electromagnetic wave absorption, due to high active dissipation phenomena such as multiple scatterings and reflections between components, 3D network pores and layers, coupling interactions between each layer, promotion of interfacial polarization, and so on. The Sandwich-Structure absorber composed of hierarchical porous Bi2MoO6, Cu microparticles, and FeNi nanoparticles was effectively constructed with optimization in layer thickness and low filler loading percentage. The microwave absorption characteristics of absorber samples varied in thickness but all less than 1.6 mm in total thickness were thoroughly examined. The as-prepared sandwich structure displayed a unique microwave absorbing behavior due to the multiple-layer structure, the dielectric dissipation property of both Bi2MoO6, Cu microparticles and the magnetic dissipation feature of FeNi nanoparticles, as well as the complementary effect between particles and layers. Minimum reflection loss (RLmini) of −45.5 dB at 5.5 GHz is obtained with proper optimization of layer order and thickness in a resin base 3-layer absorber sample with Bi2MoO6 placed as a top layer with 0.4 mm thickness, FeNi placed as a middle layer with 0.5 mm thickness, and finally Cu placed as a bottom layer with 0.7 mm thickness. The results show that the as-prepared 3-layer nanocomposite sample has a high potential for usage in microwave absorption in the low-frequency band.

Photo-enhanced electrocatalytic methanol oxidation of carbon black-modified Pt and Mo-based oxide for acidic and basic solutions

Pt nanoparticles were electrodeposited on a molybdenum-based oxide (e.g., molybdenum oxide (MoO3) and bismuth molybdate (Bi2MoO6)) modified carbon black (CB) support to study the enhancement of methanol oxidation in acidic and basic solutions with the assistance of visible light illumination. Morphology studies showed that Bi2MoO6 nanoparticles were initially anchored on the CB matrix with round 2.2 nm Pt nanoparticle decoration, resulting in a large extension of the specific active catalytic surface area (SSA) for Pt/Bi2MoO6/CB. It was found that the Pt/Bi2MoO6/CB composite catalyst offered the highest electrocatalytic activity with visible light support, showing 2 (in an acidic solution) and 18 (in a basic solution) times higher reactivity than the electrodeposited Pt/CB. Moreover, the electrocatalytic activity and stability of the prepared catalyst toward methanol oxidation with the aid of visible light were noticeably improved in both acidic and basic solutions, and the oxidation improvement was greatest in basic solutions. Therefore, the improved oxidation performance of the prepared catalysts was mostly a result of the combination of both photocatalytic and electrocatalytic procedures on Pt-based catalysts with metal oxides, resulting in enhanced catalytic activity and stability for the oxidation of methanol and CO under visible light.

Hydrangea-like TiO2/Bi2MoO6 porous nanoflowers triggering highly sensitive electrochemical immunosensing to tumor marker.

Rapid and sensitive detection of carcinoembryonic antigen (CEA) is of great significance for cancer patients. Here, molybdenum (Mo) was doped into bismuth oxide (Bi2O3) by one-pot hydrothermal method forming porous tremella Bi2MoO6 nanocomposites with a larger specific surface area than the spherical structure. Then, a new kind of hydrangea-like TiO2/Bi2MoO6 porous nanoflowers (NFs) was prepared by doping titanium into Bi2MoO6, where titanium dioxide (TiO2) grew in situ on the surface of Bi2MoO6 nanoparticles (NPs). The hydrangea-like structure provides larger specific surface area, higher electron transfer ability and biocompatibility as well as more active sites conducive to the attachment of anti-carcinoembryonic antigen (anti-CEA) to TiO2/Bi2MoO6 NFs. A novel label-free electrochemical immunosensor was then constructed for the quantitative detection of CEA using TiO2/Bi2MoO6 NFs as sensing platform, showing a good linear relationship with CEA in the concentration range 1.0pg/mL ~ 1.0mg/mL and a detection limit of 0.125pg/mL (S/N = 3). The results achieved with the designed immunosensor are comparable with many existing immunosensors used for the detection of CEA in real samples.

Structural tuning of bismuth molybdate composite photocatalyst for pollutants removal

In this study, a one-step hydrothermal method was employed to tune the structural characteristics and properties of Bi2MoO6-based composite. The manipulation of the phase composition and crystallite dimensions of Bi2MoO6 was achieved by varying the dosage of sodium molybdate, as evidenced by the XRD analyses. Moreover, the amalgamation of modified Bi2MoO6 nanoparticles with supporting materials such as kaolinite and attapulgite was observed to potentially impede the phase transition of Bi2MoO6. Emphasis was also placed on the influence of support quantity on the composite's structural attributes. Experimental results substantiated that the Bi2MoO6-based composite (BMOK-1.5/1) exhibited exceptional adsorption and photocatalytic performance in the degradation of TC and RhB under visible light exposure, particularly when three-fifths of the theoretical quantity of sodium molybdate was incorporated. The enhanced performance is attributed to the composite's large specific surface area, increased surface hydroxyl groups, and diminished recombination rate of photogenerated carriers. This study introduces a straightforward approach for regulating the structural aspects of bismuth-based photocatalysts.

Mechanochemical synthesis of CoFe2O4/Bi2MoO6 mixed metal oxide and study of its photocatalytic behavior

The synthesis of CoFe2O4/Bi2MoO6 nanoparticles and its components is reported via a mechanochemical procedure followed by calcination treatment. The results revealed successful formation of the product with a non-uniform flake-like morphology and average particles size of 47 nm. The particulate morphologies with average sizes of 60 and 20 nm were also identified for Bi2MoO6 and CoFe2O4 nanoparticles. Photocatalytic properties of the products were studied on the degradation of Rhodamine Blue (RhB) as an organic dye contaminant from aqueous solution under visible light irradiation. The results indicated a good removal efficiency of 98 % by nanocomposite. It was found Bi2MoO6 plays a main role in photocatalytic performance while magnetic CoFe2O4 provides a simple and easy way for separation and recovery of the employed photocatalyst from aqueous.

Construction of NH2-MIL-101(Fe)@Bi2MoO6 S‐scheme heterojunction for efficient and selective photocatalytic CO2 conversion to CO

Developing efficient photocatalyst to promote the conversion of CO2 into value-added chemicals remains challenging. Here, novel NH2-MIL-101(Fe)@Bi2MoO6 S-scheme heterojunctions were fabricated via a solvothermal method, in which Bi2MoO6 (BMO) nanoparticles uniformly growing on the NH2-MIL-101(Fe) (NM101) octahedrons with intimate contact interface. The resultant heterojunctions revealed significantly enhanced activity for CO2 photoreduction. The optimal performance was achieved when the content of BMO was 10 wt%, and the formation rate of CO reached 67.0 μmol·g−1·h−1 under visible light illumination (with apparent quantum efficiency of 0.09 % at 450 nm), which was 3.2-fold of individual NM101. The boosting activity benefited from the formation of S-scheme heterojunction at the NM101 @BMO interfaces, which facilitated the separation of photoinduced electron-hole pairs with strong redox ability at the interface. This S-scheme charge transfer mechanism was further validated by the in-situ XPS and fluorescence probe molecular experiment. Besides, the intermediates and preliminary mechanism of photoreaction were unraveled based on in-situ DRIFTS analysis. This work provides some novel insights for designing efficient S-scheme photocatalysts for CO2 photoreduction.

Effective Nanocomposite Based on Bi2MoO6/MoS2/AuNRs for NIR-II Light-Boosted Photodynamic/Chemodynamic Therapy.

Bi2MoO6 (BMO) nanoparticles (NPs) have been widely used as a photocatalyst to decompose organic pollutants, but their potential for photodynamic therapy (PDT) is yet to be explored. Normally, the UV absorption property of BMO NPs is not suitable for clinical application because the penetration depth of the UV light is too small. To overcome this limitation, we rationally designed a novel nanocomposite based on Bi2MoO6/MoS2/AuNRs (BMO-MSA), which simultaneously possesses both the high photodynamic ability and POD-like activity under NIR-II light irradiation. Additionally, it has excellent photothermal stability with good photothermal conversion efficiency. The as-prepared BMO-MSA nanocomposite could induce the germline apoptosis of Caenorhabditis elegans (C. elegans) via the cep-1/p53 pathway after being illuminated by light with a wavelength of 1064 nm. The in vivo investigations confirmed the ability of the BMO-MSA nanocomposite for the induction of DNA damage in the worms, and the mechanism was approved by determining the egl-1 fold induction in the mutants that have a loss of function in the genes involved in DNA damage response mutants. Thus, this work has not only provided a novel PDT agent, which may be used for PDT in the NIR-II region, but also introduced a new approach to therapy, taking advantage of both PDT and CDT effects.

Construction of high-proportion dual bismuth-based Z-scheme Bi3O4Cl/Bi2MoO6 photocatalytic system via in-situ growth of Bi2MoO6 on Bi3O4Cl for enhanced photocatalytic degradation of organic pollutants

In this study, a high-proportion dual bismuth-based Z-scheme Bi3O4Cl/Bi2MoO6 photocatalytic system was constructed via the in-situ growth of Bi2MoO6 on Bi3O4Cl for enhanced visible-light driven photocatalytic degradation of organic pollutants in wastewater. The effects of the particle ratio of Bi3O4Cl and Bi2MoO6, organic pollutant initial concentration, catalyst dosage, visible-light irradiation time, degradation kinetics and reused times on the photocatalytic activity of the Z-scheme Bi3O4Cl/Bi2MoO6 photocatalyst were investigated. Moreover, the study compares the photocatalytic degradation extents of norfloxacin, tetracycline, crystal violet, acridine orange and methylene blue using the Z-scheme Bi3O4Cl/Bi2MoO6 photocatalyst, and proposes a possible mechanism on the Z-scheme Bi3O4Cl/Bi2MoO6 photocatalytic system. The results indicate that the high-proportion dual bismuth-based Z-scheme Bi3O4Cl/Bi2MoO6 photocatalyst performs superior photocatalytic activity at a 1.0:1.0 particle ratio. The fuzzy contact interfaces can be formed between Bi2MoO6 and Bi3O4Cl nanoparticles due to the direct in-situ growth of Bi2MoO6 on Bi3O4Cl, which can provide channels for the photo-generated electron transfer to construct the Z-scheme Bi3O4Cl/Bi2MoO6 photocatalytic system. After five cycles, the Z-scheme Bi3O4Cl/Bi2MoO6 photocatalyst maintains high photocatalytic performance. During the photocatalytic degradation, the photo-generated holes play dominant roles, while the contributions of superoxide radical and hydroxyl radical remain approximate. Thus, this photocatalytic technology displays promising application prospects for handling organic contaminants, including antibiotics and dyes, in wastewater.

Synthesis and characterization of ternary NiO@Bi2MoO6–MoS heterojunction with enhanced photodegradation efficiency towards indigo carmine dye

Heterojunctions and metal oxide dopants are commonly used in binary and ternary nanocomposites to enhance photo degradability and maintain metal-free properties. This work describes the preparation of a novel NiO@Bi2MoO6–MoS complex ternary heterostructure using a simple solvothermal technique that possesses excellent photo activities for the removal of toxic Indigo carmine (InCa) dye from wastewater using a visible-illumination source. The prepared composites were characterized using various physicochemical techniques such as UV–Visible spectra, X-ray diffraction (XRD) techniques, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transforms infrared (FTIR) spectroscopy, elemental disperse X-ray (EDX) analysis, BET surface area, photoluminescence (PL), electron spin resonance (ESR) spectroscopy, and LC-MS analysis. The UV–Visible spectrophotometer confirmed that the absorption performance of the ternary NiO@Bi2MoO6–MoS composite is comprehensive in the visible light regions. NiO@Bi2MoO6–MoS exhibited the characteristic diffraction peaks of NiO and Bi2MoO6–MoS with a band gap energy (Eg) of 3.03 eV. SEM images confirmed that the synthesized composites show good phase confirmation, with particle sizes of ∼25 nm and morphologies of nanoflakes (Bi2MoO6–MoS) and nanorods (NiO@Bi2MoO6–MoS). The PL intensity of NiO@Bi2MoO6–MoS is much lower than that of Bi2MoO6 and Bi2MoO6–MoS composites, indicating a much more effective separation of photo-generated electrons and holes at the interface which in turn leads to the expected photocatalytic performance. The photocatalytic activity results showed that the degradation efficiency of NiO@Bi2MoO6–MoS for InCa dyes was 98.8%within 120 min, which is significantly superior to the binary composite Bi2MoO6–MoS (73.2%).The enhanced photo degradability of NiO@Bi2MoO6–MoSis a result of the hierarchical superstructure, enhanced visible light absorption, efficient charge transfer, and synergistic interaction between NiO, MoS, and Bi2MoO6 nanoparticles. Synergistic adsorption, effective double Z-scheme, and S-scheme mechanisms were efficient for the degradation of InCa dye into CO2, H2O, inorganic ions, and simpler products that showed excellent recyclability over five consecutive cycles.

New construction method of Bi2MoO6/kaolinite with efficient visible photocatalytic activity

Bi2MoO6/kaolinite composites were fabricated by a precipitation-calcined crystallization method, with Bi2MoO6 nanoparticles loaded on the surface of kaolinite.

Bacterial cellulose flakes loaded with Bi2MoO6 nanoparticles and quantum dots for the photodegradation of antibiotic and dye pollutants

Effective strategies to improve charge separation in semiconductor particles are critical for improving the photodegradation of organic pollutants at levels sufficient for environmental applications. Herein, Bi2MoO6 (BMOMOF), comprising both nanoparticles (NPs) and quantum dots (QDs), was synthesized from a bismuth-based metal-organic framework (Bi-MOF) precursor. Surface defects on BMOMOF, the combination of NPs and QDs, and modified energy band edges improved photogenerated charge separation and facilitated redox reactions. When compared to BMO derived from uncoordinated Bi, the BMOMOF photocatalyst (PC) was more efficient at photodegrading tetracycline hydrochloride (TCH) and ciprofloxacin (CIP), two widely-used antibiotics ubiquitous in wastewater, as well as the carcinogenic pollutant rhodamine B (RhB). BMOMOF was then loaded on the biopolymer bacterial cellulose (BC) to further enhance photocatalytic performance and facilitate the recovery of the PC after water treatment processes. The novel BMOMOF/BC photocatalytic flakes were significantly larger than pure BMOMOF, and thus easier to recuperate. Furthermore, anchoring BMOMOF on BC flakes augmented significantly the photodegradation of TCH, CIP, and RhB, mainly because hydroxyl groups in BC act as hole traps facilitating photogenerated electron-hole separation. Results obtained with BMOMOF/BC highlight promising approaches to develop optimal PCs for aqueous pollutants degradation.

In vitro biocompatibility evaluations of pH-sensitive Bi2MoO6/NH2-GO conjugated polyethylene glycol for release of daunorubicin in cancer therapy

Here, a pH-sensitive biocompatible nanocarrier system is synthesized by the combination of Bi2MoO6 nanoparticles, NH2-graphene oxide (GO), and polyethylene glycol (PEG) for loading and delivery of daunorubicin (DNR) into breast cancer cells. DNR is loaded onto the nanocarrier surface via covalent bonding, exhibiting pH-sensitive behavior so that in acidic pH, nearly 86.85% of the drug is released, but in biological pH, only about 15% of the drug is released. The resulting Bi2MoO6/NH2-GO/PEG/DNR has a high drug loading content (33.29%) and encapsulation efficiency (99.75%). By examining the toxicity of the nanocarrier-loaded drug, no adverse effect is observed on healthy cells HUVEC, and the survival rate of cancer cells MCF-7 decreases with increasing the nanocarrier concentration. Moreover, the free drug is found to be more toxic than DNR attached to the nanocarrier. The complement activation (C3 and C4 levels), prothrombin time and activated partial thromboplastin time analyses also indicate its excellent blood compatibility. The hemolysis analysis (HRs),used to evaluate the nanocarrier compatibility. the results show that even in high concentrations(5–100 μg/ml), the percentage of hemolysis is below 1.8%, which indicates that the nanocarrier is safe to blood cells. These results evidence the therapeutic nature of the biocompatible Bi2MoO6/NH2-GO/PEG, proposing it as an efficient anticancer nanocarrier for drug delivery and other biomedical application purposes.

Construction of highly efficient 0D/2D Bi2MoO6/g-C3N4 heterojunctions for visible-light-driven photodegradation of 1-naphthol

Photocatalytic degradation is an ecologically benign method of reducing organic contaminants in wastewater. To remove the pollutant 1-naphthol, highly efficient 0D/2D Bi2MoO6/g-C3N4 heterojunctions were successfully assembled by a one-step hydrothermal method, where zero-dimension (0D) Bi2MoO6 nanoparticles were firmly bonded to two-dimension (2D) g-C3N4 nanosheets. 0D/2D Bi2MoO6/g-C3N4 exhibited exceptional degradation efficiency for 1-naphthol with a removal rate of 81.5% after 60 min of visible light irradiation. The enhanced photocatalytic ability was attributed to the matched band structures and tightly connected heterojunctions, which effectively prevented the recombination of photogenerated carriers. Besides, the photodegradation mechanism was revealed by investigating the catalysts' crystal phase, morphology, physicochemical and optical properties. This work introduces a novel method for one-step preparation of 0D/2D photocatalysts and advances the utilization of photodegradation for organic pollutants.

Designing oxygen vacancy mediated bismuth molybdate (Bi2MoO6)/N-rich carbon nitride (C3N5) S-scheme heterojunctions for boosted photocatalytic removal of tetracycline antibiotic and Cr(VI): Intermediate toxicity and mechanism insight

Polymeric N-rich carbon nitride of C3N5 is being utilized as a new visible-light-driven catalyst due to its narrower bandgap (∼2.0 eV). Building step-scheme (S-scheme) heterojunction by coupling with other semiconductors especially those own oxygen vacancies (OVs) can further upgrade the photocatalytic performance of C3N5-based photocatalysts. Herein, a novel S-scheme heterojunction of OVs mediated Bi2MoO6/C3N5 was fabricated by in-situ growing Bi2MoO6 nanoparticles with OVs on C3N5 nanosheets. Benefiting from the efficient separation and transfer of high energetic charge carriers by S-scheme charge migration, enriched structural defects, as well as the close contact by the in-situ growth, the heterojunction exhibited superior visible-light photocatalytic performance toward the removal of tetracycline (TC) and Cr(VI) than C3N5, Bi2MoO6, and their mechanical mixture under visible light. The TC degradation routes and the bio-toxicity evolution of TC were explored. Moreover, the photocatalytic mechanism for TC decomposition and Cr(VI) reduction over Bi2MoO6/C3N5 with OVs were elucidated. This work presents a newfangled vision for designing promising C3N5-based S-scheme heterojunction photocatalysts for pollution control.

In Situ Formation of Bi2MoO6-Bi2S3 Heterostructure: A Proof-Of-Concept Study for Photoelectrochemical Bioassay of l-Cysteine.

A novel signal-increased photoelectrochemical (PEC) biosensor for l-cysteine (L-Cys) was proposed based on the Bi2MoO6–Bi2S3 heterostructure formed in situ on the indium–tin oxide (ITO) electrode. To fabricate the PEC biosensor, Bi2MoO6 nanoparticles were prepared by a hydrothermal method and coated on a bare ITO electrode. When L-Cys existed, Bi2S3 was formed in situ on the interface of the Bi2MoO6/ITO electrode by a chemical displacement reaction. Under the visible light irradiation, the Bi2MoO6–Bi2S3/ITO electrode exhibited evident enhancement in photocurrent response compared with the Bi2MoO6/ITO electrode, owing to the signal-increased sensing system and the excellent property of the formed Bi2MoO6–Bi2S3 heterostructure such as the widened light absorption range and efficient separation of photo-induced electron–hole pairs. Under the optimal conditions, the sensor for L-Cys detection has a linear range from 5.0 × 10−11 to 1.0 × 10−4 mol L−1 and a detection limit of 5.0 × 10−12 mol L−1. The recoveries ranging from 90.0% to 110.0% for determining L-Cys in human serum samples validated the applicability of the biosensor. This strategy not only provides a method for L-Cys detection but also broadens the application of the PEC bioanalysis based on in situ formation of photoactive materials.

A novel hierarchical nanostructured S-scheme RGO/Bi2MoO6/Bi2WO6 heterojunction: Excellent photocatalytic degradation activity for pollutants

The S-scheme heterogeneous photocatalysts have outstanding photocatalytic performance resulting from the suitable matching of band edge potential. In this study, a hierarchical hollow microsphere assembled by Bi2WO6 nanoplates and Bi2MoO6 nanoparticles were anchored on RGO to form a ternary S-scheme RGO-Bi2MoO6/Bi2WO6 (BMWG) heterojunction. Remarkably, the photocatalytic efficiency of BMWG the rhodamine B (RhB) degradation under visible light irradiation respectively exhibits 33, 4, and 2 times of enhancement compared to that of P25, Bi2WO6, and Bi2MoO6/Bi2WO6 with high photo-corrosion stability over 5 cycles. The improvement of photocatalytic activity and stability are mainly ascribed to the S-scheme heterojunction between Bi2MoO6 and Bi2WO6 and incorporation of graphene that further accelerates the separation and migration of the photogenerated charge carriers at the heterogeneous interfaces. This study provides an insight into the design and fabrication of S-scheme hierarchical nanostructured heterojunction of high photocatalytic activity.

Bi2MoO6 and Ag nanoparticles immobilized on textile by plasma-derived innovative techniques to generate antimicrobial activity

In this study, we expose various techniques based on cold plasma discharge (CPD), and more precisely aqueous-phase plasma-aided grafting (APPAG), to efficiently modify the surface of polymers as well as fabric made of natural fibers. Several directions were investigated to ultimately add a functional coating providing an antimicrobial effect to textiles. Our strategy relies on the immobilization of silver nanoparticles (AgNPs) and Bi2MoO6 (BMO) – a robust inorganic photocatalyst that can be activated by visible light – microflowers, at the surface of cotton fabric fibers. Notably, an in situ complexation-assisted precipitation route (ISCAP – an original method derived from CPD) was successfully employed to generate a very uniform coating of silver nanoparticles at the surface of organic substrates. As we demonstrate in this study, the surface functionalization with BMO and silver provides a significant protection against bacteria in dark conditions, through a bacteriostatic effect of nano silver, and under low-intensity artificial visible light (thanks to the photocatalytic effect of BMO/Ag), hence suitable for an indoor environment such as hospitals. Our composite nanomaterial, cotton/BMO/AgNPs, was assessed through antibacterial testing with Escherichia coli (E. coli) and Staphylococcus aureus (S. Aureus), showing a pronounced antimicrobial effect with both strains. This study opens prospects for the functionalization of natural or artificial fiber materials with possible applications in the field of biomedical protective equipment such as bandages, masks or technical cloths; or even photocatalysis.

PH dependent synthesis and characterization of bismuth molybdate nanostructure for photocatalysis degradation of organic pollutants.

Bismuth molybdate (Bi2MoO6) nanostructures has attracted many researches as an advanced photocalysts for the organic contaminants. In this paper, bismuth molybdate Bi2MoO6 nanoparticles were synthesized using a simple hydrothermal method at varied pH (2, 4, 6, 8, and 10) for 15h at 180°C. The results reveal the variation pH precursor solutions have a significant impact on the morphology, phase formations, and photocatalytic activity of samples. The synthesized samples at low pH level were characterized by FESEM analysis revealing Bi2MoO6 nanoplates have formed while gradually convert to Bi2MoO6 spherical nanoparticle at high PH level as shown in energy dispersive X-ray spectroscopy (DES) peaks. The X-ray diffraction patterns reveal characteristic peaks corresponding to mixed phases of Bi2MoO6 and cubic Bi4MoO9 at high pH value. The optical absorption study exhibit Bi2MoO6 nanoplates absorbed visible light with blue shift when compared to the cubic Bi4MoO9 structures. Moreover, the photocatalytic activity results revealed that nanoplates in pH = 4 sample has excellent photocatalytic activity for degradation of rhodamine (RhB), methylene orange (MO), and phenol under visible-light irradiation (λ > 400nm) as well as exhibit the photodegradation 90% of phenol within 300min.

A nano-enzymatic photoelectrochemical L-cysteine biosensor based on Bi2MoO6 modified honeycomb TiO2 nanotube arrays composite

Improving light harvesting behavior and recognition sites of sensor is an effective way to achieve highly sensitive and selective detection of nano-enzymatic photoelectrochemical (PEC) L-cysteine (Cyst). In this work, the Bi2MoO6-TiO2 composite (BMO-HTNTs) with honeycomb TiO2 nanotube arrays (HTNTs) as light harvesting unit and Bi2MoO6 nanoparticles (BMO) as recognition unit was prepared. The typical honeycomb-nanoparticle heterostructure between HTNTs and BMO improves the separation efficiency of the electron-hole pairs. Moreover, BMO nanoparticles fully dispersed on HTNTs with large specific surface area provide more sites for Cyst recognition. The composite exhibited the enhanced light absorption and higher photocurrent density at 0.2 V (vs. Ag/AgCl), which was 4 times than that of HTNTs under simulated light. Ingeniously, Cyst can not only be specifically recognized through the Bi-S bonds but also act as electron donor to scavenge the photogenerated holes of BMO-HTNTs, resulting in the increase of PEC responses. The PEC sensor showed superior analytical performance for Cyst detection with two linear regression equations in the range of 500 nM to 500 μM and a detection limit of 150 nM. The results of the enzyme-free sensor on practical urine and serum samples demonstrated its promising application in biological monitoring.