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AIP Conference Proceedings [Author(s) PROCEEDINGS OF THE 3RD INTERNATIONAL SYMPOSIUM ON CURRENT PROGRESS IN MATHEMATICS AND SCIENCES 2017 (ISCPMS2017) - Bali, Indonesia (26–27 July 2017)] - Bismuth vanadate (BiVO4) as counter electrode in the newly developed catalysis zone of modified cadmium sulfide (CdS) sensitized solar cell for hydrogen production
摘要： Recently we developed a modified quantum dot dyes sensitized solar cell (QD-DSSC) having catalysis zone extension for hydrogen production. The DSSC section comprised of CdS sensitized highly order Titanium dioxidenanotube (CdS-HOTN) immobilized on Ti plate, Na2S/S containing electrolyte, and Pt covered SnO-F (fluorine doped tin oxide) glass plate (hence Pt/SnO-F/Glass). While the catalysis zone comprised of an extension of Ti support, as cathode, and the respected counter electrode was an extension of SnO-F glass, which was covered by BiVO4 film, both from respected DSSC section. In this presentation, we will focus on the role of the BiVO4 in our newly developed system. The bismuth vanadate was prepared by co-precipitation method with ammonia and calcination to obtain a fine powder. The BiVO4 fine powder were then deposited onto SnO-F glass plate and characterized by FT-IR, UV–vis diffused reflectance spectroscopy, SEM and X-ray diffraction. The characterization results revealed that the BiVO4 film, typically, has a band gap of 2.35 eV, characteristic of IR peaks represent the –V-O-, and –Bi-O-V- bonds, having a crystal phase as BiVO4 monoclinic scheelite with a typically crystallite size of 74.06 nm. The photo-electro-chemical properties of the BiVO4 film photo-anode was investigated by a linear sweep voltammetry and multi pulse amperometry, which revealed that the current response under the visible light was 0.03 mA/cm2. Further investigation when the BiVO4 film was incorporated into the modified QD-DSSC, the system (catalysis zone section), under solely visible light, was able to split the water into hydrogen and molecular oxygen. A brief discussion of the newly developed modified QD-DSSC, especially on the role of BiVO4 counter electrode in the catalysis zone will be presented, to gain a better insight in our new type artificial photosynthesis.
关键词： water splitting,titanium dioxide nanotubes,cadmium sulfide,artificial photosynthesis,modified dyes sensitized solar cell,Bismuth vanadate
更新于2025-09-23 15:21:21
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Fabrication of Robust Nanostructured (Zr)BiVO4/Nickel Hexacyanoferrate Core/Shell Photoanodes for Solar Water Splitting
摘要： A highly conformal 10-15 nm layer of NiFe based Prussian blue co-catalyst is coated on BiVO4 electrodes. The coating boosted the photocurrent of BiVO4 electrodes by 10-fold to 3.23 mA/cm2. A low onset potential of 0.2 V and photo-corrosion inhibition for > 50 hours are also achieved.
关键词： Prussian blue,bismuth vanadate,solar water splitting,oxygen evolution catalyst
更新于2025-09-23 15:21:21
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Photocatalytic degradation of phenol wastewater over Z-scheme g-C3N4/CNT/BiVO4 heterostructure photocatalyst under solar light irradiation
摘要： A series of carbon nanotubes (CNT) modified g-C3N4/BiVO4 photocatalysts were synthesized via wet-impregnation method and evaluated via degradation of phenol under solar light irradiation. The physicochemical properties of the as-developed photocatalyst were characterized using FTIR, XRD, FESEM, XPS, SAP and DR-UV Vis. The formation of g-C3N4/CNT/BiVO4 photocatalysts resulted in remarkable enhancement in the performance in which almost six times higher degradation rate in comparison to the pristine g-C3N4 and obeyed the pseudo-first-order kinetics and Temkin adsorption model. Congruously, the synergistic interaction between 2 wt. % of CNT and 5 vol. % of H2O2 as an oxidizing agent was capable of removing 80.6 % of phenol within 120 minutes. The profound photodegradation performance monitored was attributed to the better crystallinity structure obtained as shown in XRD and XPS analysis. Furthermore, the intimate contact between the CNT, g-C3N4 and BiVO4 in the heterostructure sample as shown in FESEM micrograph images does help in allowing a smooth electron-hole pair separation and migration, resulting in more available ?OH and ?O2ˉ radicals for photocatalytic degradation activities. The possible Z-scheme reaction mechanism has been proposed and active species trapping experiments have been carried out to find the role of active radical species responsible for the phenol degradation. Additionally, the g-C3N4/CNT/BiVO4 photocatalysts retained excellent stability even after several cycles. Congruently, a mathematical representation for understanding the interaction between CNT loading and H2O2 for photodegradation of phenol using response surface methodology (RSM) was successfully generated.
关键词： phenol degradation,bismuth vanadate,carbon nanotube,wastewater,graphitic carbon nitride,photocatalyst
更新于2025-09-23 15:21:01
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Laser-Generated BiVO4 Colloidal Particles with Tailoring Size and Native Oxygen Defect for Highly Efficient Gas Sensing
摘要： To alleviate the poor sensing performance of BiVO4, developing new strategies for the fabrication of unique device with improved sensing properties is very necessary and has great practical significance. In this work, size-tailored and uniform black BiVO4 colloids with abundant oxygen vacancy were synthesized by a unique method of pulsed laser irradiation of colloidal nanoparticles (PLICN). The corresponding laser irradiation effects on the sensing properties are comparatively investigated. The results indicate that the BiVO4 nanospheres with average size of 50 nm shows best sensing properties with high sensitivity, superior selectivity, low detection limit (44 ppb) to H2S at low working temperature (75 oC). Its sensing response is over 4 times higher when comparing with that of the raw material. Further investigation manifests that laser irradiation could induce quantity of the oxygen vacancy and decrease the resistance of the sensing device, which is mainly responsible for the enhanced sensing performance. Moreover, the density functional theories (DFT) calculations suggest that the oxygen vacancies can greatly decrease the surface absorption energy with enhanced H2S absorption capability on BiVO4 surface and lower the bader charger transfer from the absorbed H2S molecules to the BiVO4, thus enabling the implementation for the enhanced gas-sensing properties.
关键词： Pulsed laser irradiation,Hydrogen sulfide,Bismuth vanadate,Nanosphere,Gas sensor
更新于2025-09-23 15:19:57
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Pulsed Laser Deposition of Bismuth Vanadate Thin Filmsa??The Effect of Oxygen Pressure on the Morphology, Composition, and Photoelectrochemical Performance
摘要： Thin layers of bismuth vanadate were deposited using the pulsed laser deposition technique on commercially available FTO (fluorine-doped tin oxide) substrates. Films were sputtered from a sintered, monoclinic BiVO4 pellet, acting as the target, under various oxygen pressures (from 0.1 to 2 mbar), while the laser beam was perpendicular to the target surface and parallel to the FTO substrate. The oxygen pressure strongly affects the morphology and the composition of films observed as a Bi:V ratio gradient along the layer deposited on the substrate. Despite BiVO4, two other phases were detected using XRD (X-ray diffraction) and Raman spectroscopy—V2O5 and Bi4V2O11. The V-rich region of the samples deposited under low and intermediate oxygen pressures was covered by V2O5 longitudinal structures protruding from BiVO4 film. Higher oxygen pressure leads to the formation of Bi4V2O11@BiVO4 bulk heterojunction. The presented results suggest that the ablation of the target leads to the plasma formation, where Bi and V containing ions can be spatially separated due to the interactions with oxygen molecules. In order to study the phenomenon more thoroughly, laser-induced breakdown spectroscopy measurements were performed. Then, obtained electrodes were used as photoanodes for photoelectrochemical water splitting. The highest photocurrent was achieved for films deposited under 1 mbar O2 pressure and reached 1 mA cm?2 at about 0.8 V vs Ag/AgCl (3 M KCl). It was shown that V2O5 on the top of BiVO4 decreases its photoactivity, while the presence of a bulk Bi4V2O11@BiVO4 heterojunction is beneficial in water photooxidation.
关键词： photoelectrochemistry,pulsed laser deposition,bismuth vanadate
更新于2025-09-23 15:19:57
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A Type II n-n staggered orthorhombic V2O5/monoclinic clinobisvanite BiVO4 heterojunction photoanode for photoelectrochemical water oxidation: Fabrication, characterisation and experimental validation
摘要： Conventional photoanode using a singular semiconductor material is not technically viable for photoelectrochemical (PEC) water oxidation owing to the properties relating to its wide band gap, sluggish charge mobility, as well as poor separation and rapid recombination of photogenerated charge carriers. The main aim of this study was to fabricate an n-n heterojunction photoanode of V2O5/BiVO4 via a facile electrodeposition synthesis method in order to overcome the technical bottlenecks encountered in conventional singular photoanode structures. Additionally, the synergistic effect of band potentials matching and conductivity difference between BiVO4 and V2O5 were studied using LSV, IMPS, EIS, HR-TEM, XRD, XPS, Raman and ultraviolet-visible spectroscopies. This was followed by the performance evaluation of the light-induced water splitting using a standard three-electrode assembly PEC cell under 1.5 AM solar simulator. Results showed that the V2O5/BiVO4 heterojunction photoanode achieved a significantly improved photocurrent density of 1.53 mA/cm2 at 1.5 V vs Ag/AgCl, which was a 6.9-fold and a 7.3-fold improvement over the individual pristine BiVO4 (0.22 mA/cm2) and V2O5 (0.21 mA/cm2), respectively. The improvement was attributed to the lower charge resistances at the FTO/semiconductor, semiconductor/FTO and semiconductor/electrolyte interfaces as well as the fast transit time (τ) of 6.4 millisecond for photo-injected electrons in the V2O5/BiVO4 heterojunction photoanode. Finally, the experimental results were used to reconstruct a theoretical band diagram in validating the heterojunction alignment between V2O5 and BiVO4 as well as in elucidating the photogenerated charge carriers transfer mechanism in the V2O5/BiVO4 heterojunction photoanode.
关键词： Bismuth vanadate,n-n heterojunction,Charge separation,Photoelectrocatalysis
更新于2025-09-19 17:15:36
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Enhanced carrier transport and bandgap reduction in sulfur-modified BiVO <sub/>4</sub> photoanodes
摘要： Recent progress on bismuth vanadate (BiVO4) has shown it to be among the highest performing metal oxide photoanode materials. However, further improvement, especially in the form of thin film photoelectrodes, is hampered by its poor charge carrier transport and its relatively wide bandgap. Here, sulfur incorporation is used to address these limitations. A maximum bandgap decrease of ~0.3 eV is obtained, which increases the theoretical maximum solar-to-hydrogen efficiency from 9 to 12%. Hard X-ray photoelectron spectroscopy (HAXPES) measurements as well as density functional theory (DFT) calculations show that the main reason for the bandgap decrease is an upward shift of the valence band maximum. Time-resolved microwave conductivity measurements reveal an ~3 times higher charge carrier mobility compared to unmodified BiVO4, resulting in a ~70% increase in the carrier diffusion length. This work demonstrates that sulfur doping can be a promising and practical method to improve the performance of wide-bandgap metal oxide photoelectrodes.
关键词： bismuth vanadate,photoelectrochemical performance,charge carrier transport,BiVO4,sulfur incorporation,bandgap reduction
更新于2025-09-11 14:15:04
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Boosting Photoelectrochemical Water Oxidation with Cobalt Phosphide Nanosheets on Porous BiVO4
摘要： Modification of semiconductor surface by cobalt-rich catalysts is an effective strategy to improve the photoelectrochemical (PEC) water oxidation kinetics and migration of photogenerated electron and hole. In this study, cobalt phosphide (CoP) nanosheet was integrated on the nanoporous bismuth vanadate (BiVO4) electrode by using the hydrothermal method. The introduction of CoP significantly improved the PEC performance of the photoanode, with a photocurrent up to 4.0 mA cm-2 at 1.23 V (versus RHE) under simulated 100 mW cm-2 irradiation, a three-fold enhancement over that obtained by the bare BiVO4. The BiVO4+CoP photoanode exhibited an impressive early onset of water oxidation, with a more than 220 mV cathodic shift of the onset potential, superior to the typical Co3O4 and Co-Pi cocatalysts modified BiVO4 photoanode. Systematic studies show that the improvement in PEC performance by CoP is mainly due to the restraint of surface charge recombination and increase in photovoltage.
关键词： photoelectrochemical,cobalt phosphide,water oxidation,bismuth vanadate (BiVO4),photoanode
更新于2025-09-10 09:29:36
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Dynamic mechanical and electric behaviors of La-doped BiVO4
摘要： Bismuth vanadate (BiVO4) is an important semiconductor with wide applications, but it is still lack of in-depth understanding for its fundamental dynamic behaviors. To address this issue, the comprehensive analysis of structure, internal friction (IF), modulus, dielectric and impedance spectra was employed to unambiguously disclose the dynamic mechanical and electric behaviors for a series of Bi1-xLaxVO4 ceramics (0 ≤ x ≤ 0.15). In the sensitive mechanical measurement, five IF peaks, corresponding modulus anomalies and high-temperature creep behavior have been observed in our Bi1-xLaxVO4 ceramics. Through analyzing their related kinetic parameters, defect formations and evolution processes, the complex evolution model of ferroelastic domains including four different stages and the origin of grain boundary relaxation are well established. As for the electric experiment, there are two apparently different activation processes in low and high temperature regions, respectively. In conjunction with structural and mechanical characterizations, we confirm that the mixed electric/oxide ionic conduction dominates from 433 to 633 K, undergoing a structural change (633-673 K) to the complicated defect conduction at higher temperatures (673-833 K). Our findings smooth the track for better realization of the fundamental dynamic behaviors as well as extending practical application of BiVO4-based material.
关键词： Bismuth vanadate,dynamic mechanical behaviors,electric behaviors,ferroelastic domains,grain boundary relaxation,electric conduction mechanism,BiVO4,La-doped
更新于2025-09-09 09:28:46
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ALD of Space-Efficient SnO2 Underlayers for BiVO4 Host-Guest Architectures for Photoassisted Water Splitting
摘要： Bismuth vanadate (BiVO4) is promising for solar-assisted water splitting. The performance of BiVO4 is limited by charge separation for >70 nm films or by light harvesting for <700 nm films. To resolve this mismatch, host-guest architectures use thin film coatings on 3D scaffolds. Recombination, however, is exacerbated at the extended host-guest interface. Underlayers are used to limit this recombination with a host-underlayer-guest series. Such underlayers consume precious pore volume where typical SnO2 underlayers are optimized with 65-80 nm. Here we examine conformal and ultrathin SnO2 underlayers with low defect density produced by atomic layer deposition (ALD). This shifts the optimized thickness to just 8 nm with significantly improved space-efficiency. The materials chemistry thus determines the dimension optimization. Lastly, we demonstrate host-guest architectures with an applied bias photon-to-charge efficiency of 0.71%, a new record for a photoanode absorber prepared by ALD.
关键词： host-guest architectures,solar-assisted water splitting,atomic layer deposition,SnO2 underlayers,Bismuth vanadate
更新于2025-09-04 15:30:14