Insights on the role of β-Bi2O3/Bi5O7NO3 heterostructures synthesized by a scalable solid-state method for the sunlight-driven photocatalytic degradation of dyes

Insight into the relationship between redox ability and separation efficiency via the case of α-Bi2O3/Bi5NO3O7

α-Bi2O3/Bi5NO3O7 heterojunctions are constructed, and show higher separation efficiency but lower photocatalytic activity. The reasons are related to the shift of energy band positions.

Electrodes for Paracetamol Sensing Modified with Bismuth Oxide and Oxynitrate Heterostructures: An Experimental and Computational Study

In this work, novel platforms for paracetamol sensing were developed by the deposition of Bi2O3, Bi5O7NO3 and their heterostructures onto screen-printed carbon-paste electrodes. An easy and scalable solid state synthesis route was employed, and by setting the calcination temperatures at 500 °C and 525 °C we induced the formation of heterostructures of Bi2O3 and Bi5O7NO3. Cyclic voltammetry measurements highlighted that the heterostructure produced at 500 °C provided a significant enhancement in performance compared to the monophases of Bi2O and Bi5O7NO3, respectively. That heterostructure showed a mean peak-to-peak separation Ep of 411 mV and a sensitivity increment of up to 70% compared to bare electrodes. A computational study was also performed in order to evaluate the geometrical and kinetic parameters of representative clusters of bismuth oxide and subnitrate when they interact with paracetamol.

Defective Bismuth Oxide as Effective Adsorbent for Arsenic Removal from Water and Wastewater

In this work, we report solid-state synthetized defective Bi₂O₃ containing Bi(V) sites as effective and recyclable arsenic adsorbent materials. Bi₂O₃ was extensively characterized, and structure-related adsorption processes are reported. Both As(V) and As(III) species-adsorption processes were investigated in a wide range of concentrations, pH values, and times. The effect of several competing ions was also tested together with the adsorbent recyclability.

Graphitic‑carbon nitride based mixed-phase bismuth nanostructures: Tuned optical and structural properties with boosted photocatalytic performance for wastewater decontamination under visible-light irradiation

To enhance the activities of advanced semiconductor photocatalysts, the charge carriers must be separated effectively. One strategy for achieving this is the use of heterogeneous structures, which can be prepared by hydrothermal synthesis and post-synthetic thermal and ultrasonic treatment. Herein, we report a mixed-phase composite of basic bismuth nitrate/pentabismuth heptaoxide nitrate (PC) prepared by hydrothermal synthesis under basic conditions and post-synthetic thermal treatment. In addition, sulfur-doped-graphitic carbon nitride (S-g-C₃N₄) was prepared and combined with PC in different ratios, denoted as PC-1, PC-2, and PC-3, using sonication-assisted treatment. The characterization of these catalysts confirmed the formation of mixed basic bismuth nitrate/pentabismuth heptaoxide nitrate phases and the composite nanostructure. The developed nanostructure showed interesting morphological features, for example, layered sheets of S-g-C₃N₄. The prepared PCs were tested for their visible light responsiveness for the photocatalytic degradation of a representative organic dye (Rhodamine B). We found that the modified photocatalysts showed superior activity to that of pristine PC. The optimal photocatalyst (PC-3) was also used to degrade methylene blue and Congo red, achieving 99% degradation. Thus, we present not only an efficient photocatalyst but also insights into the post-synthetic modification of basic bismuth nitrate/pentabismuth heptaoxide nitrate with stable carbon-based nanostructures.

Biochar-Supported BiOx for Effective Electrosynthesis of Formic Acid from Carbon Dioxide Reduction

The electrochemical reduction of carbon dioxide (CO2) to value-added chemicals and fuels has attracted worldwide interest for its potential to address various contemporary global issues such as CO2-related climate change, the earth’s carbon deficit and the energy crisis. In the development of this technology, many efforts have been focused on the design of inexpensive, eco-friendly and effective catalysts. In this work, a bismuth (Bi)-based material was simply synthesized via a scalable method and fully characterized by physical, chemical and electrochemical techniques. The catalyst material consisted of Bi/Bi2O3 nanoparticles and a biochar prevenient from the pyrolysis of brewed coffee waste. It was observed that the surface of the biochar was thoroughly decorated with nanoparticles. Due to its uniform surface, the biochar–BiOx electrode demonstrated good selectivity for CO2 reduction, showing a faradaic efficiency of more than 90% for CO and HCOOH formation in a wide potential range. Particularly, the selectivity for HCOOH reached more than 80% from −0.9 V to −1.3 V vs the reversible hydrogen electrode and peaks at 87%. Besides the selectivity, the production rate of HCOOH also achieved significant values with a maximum of 59.6 mg cm−2 h−1, implying a good application potential for biochar–BiOx material in the conversion of CO2 to HCOOH.

Physical Characterization of Bismuth Oxide Nanoparticle Based Ceramic Composite for Future Biomedical Application

Employment and the effect of eco-friendly bismuth oxide nanoparticles (BiONPs) in bio-cement were studied. The standard method was adopted to prepare BiONPs-composite. Water was adopted for dispersing BiONPs in the composite. A representative batch (2 wt. % of BiONPs) was prepared without water to study the impact of water on composite properties. For each batch, 10 samples were prepared and tested. TGA (thermogravimetric analysis) performed on composite showed 0.8 wt. % losses in samples prepared without water whereas, maximum 2 wt. % weight losses observed in the water-based composite. Presence of BiONPs resulted in a decrease in depth of curing. Three-point bending flexural strength decreased for increasing BiONPs content. Comparative study between 2 wt. % samples with and without water showed 10.40 (±0.91) MPa and 28.45 (±2.50) MPa flexural strength values, respectively, indicating a significant (p < 0.05) increase of the mechanical properties at the macroscale. Nanoindentation revealed that 2 wt. % without water composites showed significant (p < 0.05) highest nanoindentation modulus 26.4 (±1.28) GPa and hardness 0.46 (±0.013) GPa. Usage of water as dispersion media was found to be deleterious for the overall characteristics of the composite but, at the same time, the BiONPs acted as a very promising filler that can be used in this class of composites.

A Short Review on Biomedical Applications of Nanostructured Bismuth Oxide and Related Nanomaterials

In this review, we reported the main achievements reached by using bismuth oxides and related materials for biological applications. We overviewed the complex chemical behavior of bismuth during the transformation of its compounds to oxide and bismuth oxide phase transitions. Afterward, we summarized the more relevant studies regrouped into three categories based on the use of bismuth species: (i) active drugs, (ii) diagnostic and (iii) theragnostic. We hope to provide a complete overview of the great potential of bismuth oxides in biological environments.

Polarization screening-induced epitaxial growth and interfacial magnetism of BiFeO3/PbTiO3nanoplates

Single-crystal BiFeO₃/PbTiO₃nanoplates have been synthesizedviaa hydrothermal method, where BFO films selectively grew on the negative polar surface of PTO with a saturation thickness of about 18–20 nm and a room-temperature ferromagnetism.

ZnO decorated Sn3O4 nanosheet nano-heterostructure: a stable photocatalyst for water splitting and dye degradation under natural sunlight

Herein, a facile hydrothermally-assisted sonochemical approach for the synthesis of a ZnO decorated Sn₃O₄ nano-heterostructure is reported.

Temperature-Program Assisted Synthesis of Novel Z-Scheme CuBi₂O₄/β-Bi₂O₃ Composite with Enhanced Visible Light Photocatalytic Performance

Novel Z-Scheme CuBi₂O₄/β-Bi₂O₃ composite photocatalysts with different mass ratios and calcination temperatures were firstly synthesized by the hydrothermal method following a temperature-programmed process. The morphology, crystal structure, and light absorption properties of the as-prepared samples were systematically characterized, and the composites exhibited enhanced photocatalytic activity toward diclofenac sodium (DS) degradation compared with CuBi₂O₄ and β-Bi₂O₃ under visible light irradiation. The optimal photocatalytic efficiency of the composite, achieved at the mass ratio of CuBi₂O₄ and β-Bi₂O₃ of 1:2.25 and the calcination temperature of 600 °C is 92.17%. After the seventh recycling of the composite, the degradation of DS can still reach 82.95%. The enhanced photocatalytic activity of CuBi₂O₄/β-Bi₂O₃ is closely related to OH^•, h⁺ and O₂^•−, and the photocatalytic mechanism of CuBi₂O₄/β-Bi₂O₃ can be explained by the Z-Scheme theory.

Bi5O7NO3 and Ag/Bi5O7NO3 composites: one-step solution combustion synthesis, characterization and photocatalytic properties

In the present study, Bi₅O₇NO₃ and Ag/Bi₅O₇NO₃ composites, as novel efficient photocatalysts, were synthesized via a one-step solution combustion synthesis (SCS) using bismuth nitrate (Bi(NO₃)₃·5H₂O) as an oxidant, tartaric acid (C₄H₆O₆) as a fuel, and silver nitrate (AgNO₃) as an Ag source.

3D Hierarchical heterostructures of Bi2W1−xMoxO6 with enhanced oxygen evolution reaction from water under natural sunlight

Self-assembled 3D hierarchical Bi₂W_1−xMo_xO₆ heterostructures with varying x (x = 0, 0.2, 0.4, 0.6, 0.8 or 1.0) with different morphologies were synthesised via a facile one-pot solvothermal method and their photocatalytic activity towards the oxygen evolution reaction (OER) from water under natural sunlight was tested.