Structure Of BiVO4 Research Articles

Photo-induced BiVO4 to produce P25-like structure for enhancing piezo-photocatalytic activity

Piezo-photocatalysis is considered a promising pollutant treatment strategy. Herein, a simple strategy is proposed to construct lattice distortion in BiVO4 to realize an efficient piezo-photocatalytic degradation process. Specifically, the phase structure of BiVO4 is regulated by introducing different wavelengths of illumination, resulting in the homojunction formation. Compared with BiVO4 prepared under dark conditions (BVO), the VO bonds are shortened and the BiO bonds are elongated in the structure of BiVO4 synthesized under 460 nm illumination (BVO-460). Furthermore, the Tafel curve reveals that electrons flow from the monoclinic phase to the tetragonal phase. By the tetracycline hydrochloride degradation, it is found that the BVO-460 has excellent piezo-photocatalytic efficiency, attributed to the piezoelectric polarization field enhanced charge transfer. In this paper, the piezo-photocatalytic performance of BiVO4 is investigated in the insight of crystal phase structure, which provided a new idea for the application of layered bismuth-based materials in environmental purification.

Ingenious design of Ⅱ-scheme heterojunction BiVO4/COF for synergistic photocatalytic degradation of tetracycline

Photocatalytic degradation is shining as a central methods for purifying antibiotic wastewater, evoking burgeoning attention towards extraordinarily efficient photocatalysts. In this work, the BiVO4/COF (2:8) composite photocatalyst with Ⅱ-scheme heterojunction structure was prepared and employed for the photocatalytic degradation of tetracycline, which achieved degradation equilibrium within 30 min of light irradiation with the remarkable degradation rate reaching 91.56 %. Notably, the photocatalytic degradation rate of BiVO4/COF (2:8) soared to 0.06861 min−1, marking a 32.8-fold and 1.73-fold increase compared to bare BiVO4 (0.00209 min−1) and COF (0.03977 min−1) respectively. The excellent photocatalytic performance benefits from the Ⅱ-scheme heterojunction, fueled by the harmoniously compatible band structure of BiVO4 and COF. This intricate synergy enables effective separation of photogenerated electrons-holes pairs, fostering the generation of active substances ·O2− and h+, consequently amplifying the photocatalytic degradation activity against tetracycline. This work provides valuable insights and guidance for designing efficient COF-based II-scheme heterojunction photocatalysts.

Investigation of La-BiVO4/g-C3N4 photocatalytic system for efficient removal of hazardous water contaminants

The application of semiconductor photocatalysis powered by renewable energy sources for environmental remediation of emerging contaminants has gained significant research interest in recent years. Lanthanum-substituted bismuth vanadate (La-BiVO4)/graphitic carbon nitride (g-C3N4) heterojunctions were synthesized for the photocatalytic degradation of emerging water contaminants. Significantly, La³+ substitution serves as a model system for exploring the broader concept of cationic substitutions on BiVO4. By strategically replacing a portion of Bi(III) with various cations, we can potentially tailor the electronic structure of BiVO4 for enhanced photocatalytic performance. Photoelectrochemical analysis confirmed rapid charge separation and reduced resistance, leading to effective contaminant degradation. The La-BiVO4/g-C3N4 nanocomposite exhibited exceptional photocatalytic performance under simulated solar light irradiation (Xe-350W, AM 1.5 G), achieving 87.66% photooxidation of roxarsone within 150 min, surpassing g-C3N4, BiVO4, LaVO4, La-BiVO4, BiVO4/g-C3N4, and LaVO4/g-C3N4 by factors of 1.94, 1.26, 2.25, 1.39, 1.13, and 2.51, respectively. Moreover, it demonstrated 99.61% degradation of Cr(VI) after 60 min, outperforming g-C3N4, BiVO4, LaVO4, La-BiVO4, BiVO4/g-C3N4, and LaVO4/g-C3N4 by factors of 1.11, 1.81, 1.62, 1.67, 1.20, and 1.13, respectively. These findings underscore the superior photocatalytic efficacy of the La-BiVO4/g-C3N4 nanocomposite. The efficient photocatalytic activity of La-BiVO4/g-C3N4 type-II heterojunctions demonstrates its potential for real-world environmental remediation. This material offers a promising strategy for removing harmful water contaminants, thereby mitigating risks associated with water consumption.

Isotype BiVO4 heterostructure and the effect of photo-sono induced electron-hole pair

Owing to its suitable energy band and strong catalytic capacity, BiVO4 has received extensive attention in photocatalysis. Here, we suggest a straightforward approach to address the challenges of insufficient compatibility, poor charge transport characteristics, and limited surface adsorption properties commonly found in traditional BiVO4 photocatalysts. A heterojunction BiVO4 structure is developed by incorporating two distinct crystal phases within a single semiconducting material. A facile hydrothermal procedure is used to synthesize distinct crystalline phases of BiVO4 photocatalysts, viz., tetragonal, monoclinic, and monoclinic/tetragonal heterophase. The physicochemical characteristics of the pristine and isotype BiVO4 heterojunctions were characterized using various techniques. The photocatalytic activity of BiVO4 samples was examined by monitoring the degradation of rhodamine B (RhB). In order to boost the degradation reaction, ultrasonic sound waves are employed within the reaction medium. The present study examined the photocatalytic, sonocatalytic, and sonophotocatalytic activity of BiVO4 microcrystals in relation to the degradation of RhB dye. The results show that the crystalline phases of BiVO4 samples significantly influence the behaviour of photo-sono-induced charges. An interface in the monoclinic/tetragonal heterophase creates a spatial environment that facilitates charge transfer and enhances the separation of photo-sono-induced electron-hole pairs. The paper extensively examines the correlation between the behaviour of photo-sono-induced charge carriers and the level of sonophotocatalytic activity. This would provide greater insight into the intrinsic reasons for the enhancement in sonophotocatalytic activity.

Microwave Synthesis of (g‐C3N4)−BiVO4: Selective Adsorption and Photocatalytic Activity Towards Dye Degradation

AbstractPhotocatalytic degradation of pollutants has been extensively studied. Among the investigated photocatalysts, BiVO4 has emerged as a very promising material. BiVO4 is known for its narrow band‐gap energy suitable for solar‐driven reactions; however, it is subjected to challenges such as charge recombination and slow electron transfer kinetics. Combining BiVO4 with g‐C3N4 proves promising, aligning energy levels and leveraging unique charge transport properties to enhance dye degradation under visible light. This study reports a novel synthesis of g‐C3N4−BiVO4 heterojunction through in‐situ urea pyrolysis, ensuring homogeneous dispersion. While maintaining the monoclinic structure of BiVO4, the heterojunction exhibits increased surface area and a more negative zeta potential, influencing catalyst‐substrate to be degraded interactions. Adsorption studies reveal distinct behaviors with cationic dyes (MB and RhB) forming multilayers, hindering light absorption, and reducing photocatalytic efficiency. Conversely, the heterojunction performs efficiently with the anionic MO dye. Photoelectrochemical studies show that the heterojunction has succeeded in promoting the separation of photogenerated charges. The study lays the groundwork for optimizing synthesis methods and designing nanocomposites with superior photocatalytic activities.

SYNTHESIS OF NICKEL-DOPED BIVO4 MATERIALS BY HYDROTHERMAL METHOD AND EVALUATE THE PHOTOCATALYTIC ABILITY TO DECOMPOSE METHYLENE BLUE UNDER VISIBLE LIGHT

Ni-doped BiVO4 photocatalysts were successfully synthesized by hydrothermal method. The catalytic samples were characterized by scanning electron microscopy (SEM), UV-vis diffuse reflection spectroscopy (DRS), photoluminescence spectroscopy (PL) and X-ray diffraction (XRD). Based on the results of PL spectrum analysis, the electron-hole recombination phenomenon is limited by the presence of the second metal Ni in the structure at Bi3+ positions. The catalyst materials at the Ni doping ratios all have the monoclinic-scheelite BiVO4 structure as shown by the XRD and Raman methods. The photocatalytic ability of methyl blue (MB) on the Ni/BiVO4 catalyst was studied under visible light irradiation in order to contribute to reducing the current environmental pollution problem. The removal efficiency of MB varies with the doping ratio of Ni/BiVO4, reaching the highest decomposition efficiency of 84.77% in the 5% mol Ni sample, which is 30% higher than that of the BiVO4 sample. The BiVO4 material modified with Ni gives a high photocatalytic efficiency of organic pigment decomposition under visible light indicates the potential improvement in the efficiency of a material for existing applications and exploit many new applications in the future.

Exploring the electronic structure of BiVO4 thin films using energy-resolved electrochemical impedance spectroscopy

Bismuth vanadate (BiVO4) is a promising photoelectrochemical water-splitting semiconductor. This study focuses on elucidating the electronic structure of BiVO4 by analyzing energy-resolved electrochemical impedance spectroscopy (ER-EIS) data. The primary objective is to demonstrate the effectiveness of the ER-EIS, which is typically applied to organic semiconductors, in estimating the band edge positions of BiVO4 films deposited on FTO substrates.The impedance spectra analysis as a function of an applied overpotential permits an estimation of the density of states, where the limits correspond to the valence (VB) and conduction band (CB) edge positions that determine the redox reactions the semiconductor can promote. The energy difference between the CB and VB corresponds to the material's band gap (Eg). The calculated Eg using ER-EIS closely matches the reported optical properties of the material, and the energy positions of the VB and CB align with the reported values for BiVO4.

STRUCTURAL, OPTICAL, AND VISIBLE-LIGHT DRIVEN PHOTACATALYTIC PROPERTIES OF Yb-DOPED BiVO4 NANOPARTICLES PREPARED VIA RAPID SONOCHEMICAL PROCESS

This work represents the synthesis and structural, morphological, and optical characterization of rare-earth Yb-doped BiVO4 materials with different Ytterbium (Yb3+) contents (0% - 5%). Yb-doped BiVO4 specimens in form of fine nanoparticles were synthesized by a rapid and facile sonochemical process. The structural and morphological characterizations were observed by X-ray diffraction technique (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Important optical properties of the prepared samples were investigated by the diffuse reflectance technique and the corresponding optical band gaps were calculated by the mean of the Kullbelka-Munk equation. From the characterized results, it is acknowledged that incorporated Yb dopant has a significant effect on the crystalline structure of BiVO4 by reducing in monoclinic phase in the pristine sample while the increasing Yb doping composition resulted in the mixed phases of monoclinic and tetragonal phases since Yb3+ ions could probably induce the stabilization of the tetragonal phase in BiVO4 material. Moreover, extensive doping with Yb3+ exhibits considerable influence on not only structural but also optical and relevant visible - driven photocatalytic properties of BiVO4 by means of the color degradation of RhB dye solution.

Sulfur doping improves the weak adsorption on BiVO4 (0 1 0) facet to enhance the oxygen evolution performance

Photoelectrochemical (PEC) water splitting is one of the most effective methods for sustainable hydrogen production, but the undesirable binding between the oxygen-containing intermediates and active sites limits the performance of the oxygen evolution reaction (OER) of BiVO4 (0 1 0) crystal. Our density functional theory (DFT) calculations show that non-metallic sulfur doping can effectively improve this weak interaction on the surface by tuning the electronic structure of BiVO4. The introduction of the S atom greatly improves the photoelectric properties. The band gap reduces from 2.22 eV to 1.51 eV, favoring visible light absorption and electronic conductivity. The effective mass of the electrons reduces from 1.55 me to 0.76 me, indicating carrier mobility increases. The effective mass ratio reduces from 1.04 to 0.54, meaning the photogenerated electron-hole recombination is suppressed. More importantly, S doping-induced charge rearrangement promotes more charges distributed around the active site Bi atom, greatly improving the interaction between the oxygen-containing intermediate and the surface during the OER process, and therefore the OER overpotential reduces to 0.34 V. These interesting findings may provide an important reference for the design of high-efficiency two-dimensional semiconductor photocatalysts for the OER.

Domestic microwave-assisted synthesis of Pd doped-BiVO4 photocatalysts

Palladium-doped bismuth vanadate (Pd-doped BiVO4) with different amounts of palladium have been successfully synthesized via domestic microwave-assisted method in an aqueous medium. XPS spectra verified that valence states of XPS spectra verified that the presence of Pd2+ species in Pd-doped BiVO4, while the valence state of Bi was observed as Bi3+. The XRD results implied that Pd doping can change the phase structure of BiVO4 from tetragonal to monoclinic, thus a mixture of monoclinic and tetragonal phase was detected in Pd-doped BiVO4. Field emission scanning electron microscopy (FESEM) revealed the mixed particle morphologies between them with EDX line scans of elements Bi, V, O and Pd. The photoluminescence spectroscopy (PL) results demonstrated that the forming Pd-BiVO4 depressed the recombination of photogenerated charges as well as the decreased of band gap determination from DRS, and photocatalytic performance was improved by the substitution of Pd2+ for Bi in BiVO4. The photocatalytic activities of the prepared samples were evaluated by degrading malachite green (MG) under visible-light irradiation for 150 min. The 2.0 wt%Pd doping exhibited the highest photocatalytic activity (98 %) while photocatalysis of 20 % was achieved by MG solution without catalyst. The photodegradation rate of the 2.0 wt% Pd-doped BiVO4 for MG removal was 5 times greater than that of a single BiVO4 and it can also be reused three times. The proposed mechanism of the enhanced photocatalytic activity was discussed. A possible mechanism of Pd-doped BiVO4 on the enhanced photocatalytic activity was also proposed.

(Invited) Light-Induced Structural Deformations in BiVO4 Photoanodes

Monoclinic scheelite bismuth vandate (BiVO4) stands as one of the best performing thin film metal oxide photoanodes investigated to date. However, these desirable photoelectrochemical performance characteristics are surprising given the driving force for free charge carriers to self-trap as polarons. For the case of electrons, localization at vanadium sites leads to formation of small electron polarons with a large, thermally activated hopping barrier of several hundred meV. For the case of holes, several experimental and theoretical studies have indicated polaron formation. However, despite the importance of photogenerated hole extraction for photoanode function, significant uncertainties remain regarding the degree of hole localization, the associated structural configurations, and the transport barriers. In this work, we apply time resolved optical pump/X-ray diffraction probe experiments to investigate light excitation-induced structural transformations of BiVO4. At low pump fluences, we observe a distinct, non-thermal response that indicates increased symmetry and a partial relaxation of the monoclinic distortion within the BiO8 dodecahedra. We rationalize this finding in terms of the underlying electronic structure of BiVO4, photo-induced depopulation of valence band states, and the nature of the monoclinic-to-tetragonal phase transformation. The resulting structural change is expected to increase hole localization and play a key role in the formation and structure of photo-induced hole polarons within the material. Complimentary electronic transport and optical pump-probe spectroscopies provide additional support for this interpretation and shed light on the underlying mechanisms of polaron formation, transport, and recombination in this promising photoanode material.

All Solution-Processed Inorganic, Multilevel Memristors Utilizing Liquid Metals Electrodes Suitable for Analog Computing.

Herein, we report a solution-processable memristive device based on bismuth vanadate (BiVO4) and titanium dioxide (TiO2) with gallium-based eutectic gallium-indium (EGaIn) and gallium-indium-tin alloy (GaInSn) liquid metal as the top electrode. Scanning electron microscopy (SEM) shows the formation of a nonporous structure of BiVO4 and TiO2 for efficient resistive switching. Additionally, the gallium-based liquid metal (GLM)-contacted memristors exhibit stable memristor behavior over a wide temperature range from -10 to +90 °C. Gallium atoms in the liquid metal play an important role in the conductive filament formation as well as the device's operation stability as elucidated by I-V characteristics. The synaptic behavior of the GLM-memristors was characterized, with excellent long-term potentiation (LTP) and long-term depression (LTD) linearity. Using the performance of our device in a multilayer perceptron (MLP) network, a ∼90% accuracy in the handwriting recognition of modified national institute of standards and technology database (MNIST) was achieved. Our findings pave a path for solution-processed/GLM-based memristors which can be used in neuromorphic applications on flexible substrates in a harsh environment.

Atmospheric electrostatic induction on carrier transfer in volumetric photoelectrochemical system with MXene-modified electrodes

With WO3/BiVO4/MXene ternary composite layers as a working electrode, a smart volumetric photoelectrochemical system using electrostatic bias voltage inducted by atmospheric electric field was developed. Under single sun illumination and 0.8 V hardwired bias, the current response of the ternary electrode is 1.15 mA cm−2, which is 1.31 times higher than that of the WO3/BiVO4 electrode, mainly due to the higher charge transfer rate between the MXene layer and the BiVO4 structure. Further, the response of the ternary electrode increases to 1.39 mA cm−2 at an extra atmospheric electric field of 1100 V m−1. It can be demonstrated that the effect of the atmospheric electric field can be regarded as an extra hardwired bias of 0.101 V in the system. The experimental results reveal that the native carriers, including inducted electron/holes in MXene and BiVO4, and carriers in the electrolyte, are all effectively excited by the electrostatic induction of atmospheric electric field.

Synthesis and characterization of porous BiVO4 thin films: the effect of structural defects on photoelectrochemical properties

BiVO4 thin films with thickness of ~ 1.3 μm were deposited on ITO substrate via pulsed-spray pyrolysis deposition. X-ray diffraction pattern revealed that BiVO4 layers have been crystallized in tetragonal scheelite phase with average crystallite size of ~ 16 nm. According to UV-visible absorption spectra, a band gap energy of ~2.47 eV was determined for the synthesized layers. Scanning electron microscopy observations indicated that a porous BiVO4 structure with average pore diameter of ~ 162 nm and worm-like fine particle diameter of ~ 208 nm has been synthesized. Oxygen vacancies have been induced into the layers via an electrochemical reduction treatment (ET). This employed process increased the surface-related capacitance by about 6 times. A double charge transport resistance and half capacitance for Helmholtz layer was determined after ET, indicating electron transfer from space charge layer to Helmholtz layer upon ET. Using electrochemical impedance spectroscopy, it was found that effective charge carrier life time inside the BiVO4 thin films increased to ~25 ms which is 2-fold longer than the time before electrochemical reduction treatment.

Structural and photocatalytic properties and X-ray absorption spectroscopic study of BiVO4 nanoparticles incorporated with Fe synthesized by sonochemical method

In this work, Fe-incorporated BiVO4 nanoparticles with different Fe-loading contents (0–4%) were synthesized via one-step sonochemical process. Crystal structure of all samples was investigated by X-ray diffraction technique (XRD). XRD patterns obviously show the main structure of monoclinic BiVO4 structure. The secondary phase is found in the form of Fe-based oxide as a hematite Fe2O3 phase at for Fe-loading contents ≥ 2%. Relevant chemical bonding of as-synthesized samples was carried out by Raman spectroscopy indicating the fundamental vibration with various vibration modes of VO43− tetrahedron and V–O band, respectively. Morphological structure of pure BiVO4 shows rod-like structure while 1–4%Fe-incorporated BiVO4 display different morphologies. The chemical compositions and oxidation numbers of all elements of the samples were carried out via X-ray photoelectron spectroscopy (XPS). XPS spectra indicate the existence of all elements on their surface and the oxidation states of all elements are clearly scrutinized. Local structure of all samples was investigated to interrogate the local atomic site of Fe atoms by X-ray absorption spectroscopy (XAS). The normalized Fe K-edge XANES spectra of all samples indicate that the local atomic site of Fe atoms would not replace in local sites of either Bi or V sites in BiVO4 crystal verified by simulated XANES spectra. However, the specific features of measured XANES spectra of all samples corresponds to the Fe K-edge XANES spectra of Fe2O3 and BiFeO3 structure suggesting that local structure of all samples are formed to Fe-based oxide between Fe2O3 and BiFeO3 structure. Fitting EXAFS spectra of 1–4%Fe-incorporated were practically conducted by artemis program with Fe2O3 and BiFeO3 used as structural models to identify local atomic environment of Fe atoms. Results show agreeable fitting with their structural models and reveal pertinent information of localization of Fe atoms. Optical properties of the samples were analyzed by UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS). DRS results exhibit the absorption edge in visible range of all samples. Meanwhile, influence of Fe loading contents into pure BiVO4 displays to confirm the red-shift on the absorption edge in visible range to higher wavelength, which suggests the lower optical band gap of pure BiVO4. The optimized photocatalytic degradation of RhB was performed by 4%Fe–BiVO4 with 82% decolorization under visible-light irradiation within 10 min and exhibited rate constant at 0.150 min−1.

Simple Fabrication of BiVO4 Thin Films Synthesized by Modified SILAR Method: Effect of Film Thickness

In this study, BiVO4 photoanodes were synthesized using a simple and inexpensive modified successive ionic layer adsorption and reaction (SILAR) method. In particular, the effect of the number of SILAR cycles on the photoelectrochemical (PEC) properties of BiVO4 was evaluated. Scanning electron microscopy analysis revealed the porous surface morphology of the BiVO4 thin layers with irregularly shaped particles formed on the surface of fluorine-doped tin oxide substrates. The crystal structure of BiVO4 was confirmed using X-ray diffraction analysis. The ultraviolet–visible spectrophotometry results indicated that the bandgap energy of the deposited film was approximately 2.4 eV. In addition, the PEC properties of the BiVO4 photoanodes using potentiostat were analyzed. The linear sweep voltammetry curves revealed that the photocurrent density of the BiVO4 samples increased with the increasing number of m-SILAR cycles, and a maximum photocurrent density of approximately 0.83 mA cm−2 was achieved for the BVO-35. These results suggest that an efficient photoelectrode for compact PEC cells can serve as a basis for development.

Near-infrared-emitting upconverting BiVO4 nanoprobes for in vivo fluorescent imaging

Near-infrared (NIR) emitting BiVO4:Yb3+,Tm3+ nanoparticles are synthesized by a new solvothermal strategy using solvents of oleic acid and methanol. The obtained BiVO4:Yb3+,Tm3+ samples show an average particle size of ≈164 nm and exhibit an asymmetry monoclinic crystal structure of BiVO4. At NIR excitation of 980 nm, the BiVO4:Yb3+,Tm3+ sample exhibits a nearly single NIR emission at ≈796 nm with extremely weak blue emissions from Tm3+ ions. These high-energy visible emissions are absorbed by the semiconducting host of BiVO4 that possesses a bandgap of ≈2.2 eV. Therefore, the NIR excitation to a single intense NIR emission fluorescent BiVO4 materials could be a potential ideal probe for deep-tissue high-resolution bioimaging. To validate the ability of BiVO4 materials for bio-applications, we conduct the cytotoxicity experiments. The results show that the cytotoxicity of HeLa cells is negligible at a concentration of 0.2 mg/ml of BiVO4:Yb3+,Tm3+ , and the cell viability approaches 90% at a high dosage of 0.5 mg/ml. The Daphnia magna and Zebrafish treated with nanoparticles (0.5 mg/ml) display bright NIR emission without any background, indicating the excellent in vivo fluorescent imaging capacity of BiVO4:Yb3+,Tm3+ nanoparticles. Our findings offer an environment-friendly strategy to synthesize BiVO4 UCL nanophosphors and provide a promising new class of fluorescent probes for biological applications.

Stress-induced BiVO4 photoanode for enhanced photoelectrochemical performance

BiVO4 is a promising and environmental-benign photoanode material. However, the photoelectrochemical properties of BiVO4 are confined to its low charge separation efficiency. Herein, we have developed a simple method to introduce stress into the BiVO4 photoanode via the change of the unit cell volume of VO2 near the phase transition temperature. In this way, the crystal structure of BiVO4 is caused to be distorted and thus improve the photoelectrochemical properties of the BiVO4 photoanode, making the surface photopotential of the BiVO4-V photoanode nearly double that of the bare BiVO4 photoanode. At room temperature, the photocurrent density of the BiVO4-V photoanode is 2.35 times that of the BiVO4 photoanode. Intriguingly, at 85 °C, the photocurrent density of the BiVO4-V photoanode is as high as 6.8 times that of the BiVO4 photoanode. Moreover, the photocurrent density of the BiVO4-V photoanode could reach 80% of the theoretical photocurrent density of the BiVO4 photoanode at 85 °C in the presence of the sacrificial agent Na2SO3. This work illustrates a new stress engineering strategy to improve the photoelectrochemical properties of BiVO4 photoanodes and is expected to be applicable to other semiconductor photoanodes.

Boosting solar water oxidation activity of BiVO4 photoanode through an efficient in-situ selective surface cation exchange strategy

The sluggish kinetics for water oxidation is recognized as one of the major problems for the unsatisfied photoelectrochemical (PEC) performance. Herein, we developed a feasible strategy based on in-situ selective surface cation exchange, for activating surface water oxidation reactivity toward boosted PEC water oxidation of BiVO4 photoanodes with fundamentally improved surface charge transfer. The as-constructed Co/BiVO4 photoanodes exhibit 2.6 times increase in photocurrent density with superior stability, in comparison to those of pristine counterpart. Moreover, the faradaic efficiency of as-fabricated photoanode can be up to ∼ 95% at 1.23 V (vs. RHE). The unique selective replacement of Bi by Co on the surface could modify the electronic structure of BiVO4 with reduced energy barrier of the deprotonation of OH* to O, thus favoring the overall excellent PEC performance of Co/BiVO4 photoanode.

Improving the photocatalytic activity of tetragonal [formula omitted] with zircon-type structure through [formula omitted] doping; Ab initio calculations

In this paper we studied the effects of the concentration of W as a doped atom on the V lattice site on the electronic and optical properties of tetragonal zircon-type BiVO4 structure. The calculations were performed by the first-principles density functional theory WIEN2k code. The doping strategy was targeting V atoms substituted by W atoms using the same lattice parameters as pure BiVO4 structure. To avoid the self interaction of impurities, the supercell method was adopted ensuring a sufficient length between the impurities in all directions. For all considered concentrations, the optical properties in the visible light range of λ≥550nm are improved over the undoped BiVO4.