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Hierarchical ZnO microspheres embedded in TiO2 photoanode for enhanced CdS/CdSe sensitized solar cells
摘要: Control of structural and compositional characteristics of photoanodes is a crucial step toward rapid transport of charges and high efficiency loading of dye or quantum dots in case of solar cell application. A hierarchical ZnO microspheres (ZMS) and TiO2 hybrid photoanode film was prepared for improved CdS/CdSe quantum dot sensitized solar cells (QDSCs). The addition of ZMS into TiO2 electrode films resulted in both increased short circuit current density (Jsc) and open circuit voltage (Voc). Such an improvement is ascribed to the increased light harvesting owing to scattering by ZMS and the reduced charge recombination due to the surface modification. TiO2/ZMS hybrid photoanode displays superior charge injection/transport performance due to the ZMS with unique hierarchical structure, providing charge transfer continuity and multiple electron transport channels for timely electron transport. As a result, the Jsc, Voc, and the photovoltaic conversion efficiency (PCE) were all remarkably enhanced with the insertion of hierarchical ZMS though varied appreciably with the amount of ZMS. Thus, the designed TiO2/ZMS heterostructure based QDSCs with an optimizing ZMS ratio of 20 wt% achieved a PCE of 5.99%, which is about 35% increase of the efficiency for the devices without ZMS (4.45%).
关键词: electron transport,ZnO microspheres,charge injection,quantum dot-sensitized solar cells,photoanode,light scattering
更新于2025-11-14 17:04:02
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A microfluidic all-vanadium photoelectrochemical cell with the N-doped TiO2 photoanode for enhancing the solar energy storage
摘要: In this work, the nitrogen-doped TiO2 photocatalyst is synthesized and applied in a microfluidic all-vanadium photoelectrochemical cell for enhancing the solar energy storage. The use of the nitrogen-doped TiO2 photoanode and the minimization design can ensure the visible-light response, increased specific surface area, vigorous pore structure and enhanced photon and mass transport as well as more uniform light distribution. Various characterizations are performed to evaluate the developed photocatalyst and microfluidic all-vanadium photoelectrochemical cell. The results confirm that the developed nitrogen-doped TiO2 photoanode can provide both the extended absorption spectrum and the small anatase crystal size as well as the obviously enlarged specific surface area with plentiful pore structure. Because of these merits, the microfluidic all-vanadium photoelectrochemical cell with the nitrogen-doped TiO2 photoanode yield the average photocurrent density of 0.103 mA/cm2 during the long-term operation, which is much higher than those with the un-doped TiO2 photoanode (0.086 mA/cm2) and commercial P25 TiO2 photoanode (0.073 mA/cm2), presenting 19.8% and 41% improvements, respectively. The results demonstrate not only the promotion of the vanadium reversible redox pairs conversion but also the inherently excellent stability by the nitrogen-doped TiO2 photoanode.
关键词: Photoanode,N-doped TiO2 photocatalyst,Conversion rate,Microfluidic all-vanadium photoelectrochemical cell,Solar energy storage
更新于2025-11-14 17:03:37
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Visible light driven photoelectrocatalysis on a FTO/BiVO4/BiOI anode for water treatment involving emerging pharmaceutical pollutants
摘要: Contamination of water bodies by harmful and recalcitrant organic substances is a global challenge. A promising technique for removing these organics from water/wastewater is photoelectrocatalytic oxidation which combines electrolytic and photocatalytic processes. Herein, we report the degradation of emerging pharmaceutical pollutants e acetaminophen and cipro?oxacin e at a BiVO4/BiOI photoanode under visible irradiation via photoelectrocatalytic process. The BiVO4/BiOI was electrodeposited on a FTO glass and characterised with XRD, SEM, EDS and diffusive re?ectance UVeVis. The results con?rmed the successful electrodeposition of BiVO4/BiOI on the glass substrate. Mott-Schotty plots con?rmed the formation of p-n heterojunction between the two electrodeposited semiconductors. The calculated charge carrier density of BiVO4/BiOI was higher than those of pristine BiVO4 and BiOI. The binary electrode also gave improved photocurrent response compared with unitary electrodes. Degradation ef?ciencies of 68% and 62% were achieved upon the application of the prepared photoanode (FTO/BiVO4/BiOI) in PEC degradation of acetaminophen and cipro?oxacin respectively using a bias potential of 1.5 V within 2 h. A synthetic pharmaceutical wastewater containing a mixture acetaminophen and cipro?oxacin was also treated with the photoanode. The photoanode was also effective in the degradation of dye. The ?ndings of this study suggest the suitability of the prepared photoanode for the photoelectrocatalytic degradation of organic pharmaceutical pollutants in wastewater.
关键词: Cipro?oxacin,p-n heterojunction photoanode,Photoelectrocatalytic degradation,Bismuth oxyiodide,Acetaminophen,Bismuth vanadate
更新于2025-11-14 14:48:53
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Ferroelectric enhanced photoelectrochemical water splitting in BiFeO3/TiO2 composite photoanode
摘要: A facile sol-gel methodology was used to synthesize single-phase BiFeO3 (BFO) film on TiO2 photoanode to improve photoelectrochemical (PEC) water-splitting efficiency. The BFO films with controllable thickness induced a considerable ferroelectric polarization under bias voltage, which effectively tuned the electric band bending of BFO/TiO2. The photocurrent density of the as-prepared BFO-5/TiO2 could reach up to 11.25 mA/cm2, which is over 20 times higher than that of bare TiO2. Moreover, the positively poled BFO-5/TiO2 photoanode yielded a photocurrent density of 28.75 mA/cm2 at 1.5 V vs.SCE under AM 1.5G illumination. This work suggests that BFO/TiO2 with combined ferroelectric and semiconducting features could be a promising solution to improve PEC performance by concurrently promoting the light absorption and charge-separation and transportation properties.
关键词: BiFeO3,Ferroelectric polarization,Photoanode,Water-splitting
更新于2025-09-23 15:23:52
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Metal–organic framework coated titanium dioxide nanorod array p–n heterojunction photoanode for solar water-splitting
摘要: This paper presents a p–n heterojunction photoanode based on a p-type porphyrin metal–organic framework (MOF) thin film and an n-type rutile titanium dioxide nanorod array for photoelectrochemical water splitting. The TiO2@MOF core–shell nanorod array is formed by coating an 8 nm thick MOF layer on a vertically aligned TiO2 nanorod array scaffold via a layer-by-layer self-assembly method. This vertically aligned core–shell nanorod array enables a long optical path length but a short path length for extraction of photogenerated minority charge carriers (holes) from TiO2 to the electrolyte. A p–n junction is formed between TiO2 and MOF, which improves the extraction of photogenerated electrons and holes out of the TiO2 nanorods. In addition, the MOF coating significantly improves the efficiency of charge injection at the photoanode/electrolyte interface. Introduction of Co(III) into the MOF layer further enhances the charge extraction in the photoanode and improves the charge injection efficiency. As a result, the photoelectrochemical cell with the TiO2@Co-MOF nanorod array photoanode exhibits a photocurrent density of 2.93 mA/cm2 at 1.23 V (vs. RHE), which is ~ 2.7 times the photocurrent achieved with bare TiO2 nanorod array under irradiation of an unfiltered 300 W Xe lamp with an output power density of 100 mW/cm2.
关键词: p–n junction,photoanode,titanium dioxide,metal-organic framework,water-splitting
更新于2025-09-23 15:23:52
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Simultaneous Cr(VI) removal and bisphenol A degradation in a solar-driven photocatalytic fuel cell with dopamine modified carbon felt cathode
摘要: In this work, a carbon felt cathode modified by dopamine (DPA/CF) was explored to enhance the cathodic reduction of Cr(VI) in a two chambers photoelectrochemical system, which was driven by solar light irradiation using BiVO4 photoanode. In the anode chamber, the bisphenol A (BPA) decomposition can be significantly improved by increasing pH to 8. The electron-hole pairs photogenerated on the surface of BiVO4 were efficiently separated by the application of the DPA/CF cathode. At the optimal conditions, 86% of low-concentration BPA was removed within 60 min. In the cathodic chamber, 80% of Cr(VI) was removed at pH of 4. Based on the XPS and electrochemical analyses, it was proposed that the positively-charged groups on the DPA/CF cathode led to the multilayer adsorption of Cr(VI) anions, which enhanced the reduction of Cr(VI) with the electrons generated on the BiVO4. On the other hand, the CeO groups on the DPA/CF electrode also played an important role as electron transfer mediator for Cr(VI) reduction. The prepared DPA/CF cathode associated with BiVO4 photoanode could be a potential application for efficient removal of Cr(VI) and organic pollutants under solar light irritation.
关键词: BiVO4 photoanode,Carbon felt cathode,Dopamine,Cr(VI),Solar photocatalysis,BPA
更新于2025-09-23 15:23:52
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Porous WO3 monolith-based photoanodes for high-efficient photoelectrochemical water splitting
摘要: We report a successful fabrication of low-cost, high-efficient, structurally-rigid, porous WO3 photoelectrochemical (PEC) catalysts using polystyrene as the template by a sol-gel method and a high-temperature annealing treatment. The scanning electron microscopy and Brunauer-Emmett-Teller surface analysis results indicate that such WO3 monoliths possess a porous structure and a large specific surface area, which can supply lots of photogenerated charge transfer pathways as well as more surface PEC active sites. Compared with a commercially available WO3, our highly porous WO3 PEC catalysts show an excellent PEC water splitting activity. Particularly, the porous WO3 photoanodes calcinated in the presence of oxygen atmosphere at 450 °C for 7 h show the best PEC performance exhibiting the photocurrent density of 0.97 mA/cm2 at 1.23 V versus reversible the hydrogen electrode and the incident photon-to-current conversion efficiency up to 48.9% at 420 nm in 0.5 M Na2SO4 electrolyte under AM 1.5 G irradiation. Such excellent PEC performance is due to the high porosity of the WO3, promoting the fast transfer and the separation rate of photogenerated carriers during the PEC water splitting process.
关键词: Water splitting,Porous structures,Energy conversion,WO3,Photoanode
更新于2025-09-23 15:23:52
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Oxynitride Thin Films versus Particle-Based Photoanodes: a Comparative Study for Photoelectrochemical Solar Water Splitting
摘要: The solar water splitting process assisted by semiconductor photocatalysts attracts growing research interests worldwide for the production of hydrogen as a clean and sustainable energy carrier. Due to their optical and electrical properties several oxynitride materials show great promise for the fabrication of efficient photocatalysts for solar water splitting. This study reports a comparative investigation of particle- and thin films-based photocatalysts using three different oxynitride materials. The absolute comparison of the photoelectrochemical activities favors the particle-based electrodes due to the better absorption properties and larger electrochemical surface area. However, thin films surpass the particle-based photoelectrodes due to their more suitable morphological features that improve the separation and mobility of the photo-generated charge carriers. Our analysis identifies what specific insights into the properties of materials can be achieved with the two complementary approaches.
关键词: Oxynitride,pulsed laser deposition,photoelectrochemistry,thin films,solar water splitting,photoanode
更新于2025-09-23 15:23:52
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Stable Molecular Surface Modification of Nanostructured, Mesoporous Metal Oxide Photoanodes by Silane and Click Chemistry
摘要: Binding functional molecules to nanostructured mesoporous metal oxide surfaces provides a way to derivatize metal oxide semiconductors for applications in dye-sensitized photoelectrosynthesis cells (DSPECs). The commonly used anchoring groups, phosphonates and carboxylates, are unstable as surface links to oxide surfaces at neutral and high pH, leading to rapid desorption of appended molecules. A synthetically versatile molecular attachment strategy based on initial surface-modification with a silyl azide followed by click chemistry is described here. It has been used for the stable installation of surface-bound metal complexes. The resulting surfaces are highly stabilized toward complex loss with excellent thermal, photochemical, and electrochemical stabilities. The procedure involves binding 3-azidopropyltrimethoxysilane (APTMS) to nanostructured mesoporous TiO2 or tin-doped indium oxide (ITO) electrodes by silane attachment followed by azide-terminated, Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reactions with an alkyne-derivatized ruthenium(II) polypyridyl complex. The chromophore-modified electrodes display enhanced photochemical and electrochemical stabilities compared to phosphonate surface binding with extended photoelectrochemical oxidation of hydroquinone for more than ~6 h with no significant decay.
关键词: DSPECs,photostability,stability,silane chemistry,electrostability,Ru(II) polypyridyl complexes,click chemistry,Dye-sensitized,photoanode
更新于2025-09-23 15:22:29
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CuO/ZnO Heterojunction Nanoarrays for Enhanced Photoelectrochemical Water Oxidation
摘要: Photoelectrochemical (PEC) water splitting offers a promising route for producing chemical energy from abundant solar energy, but a bottleneck remains for PEC practical applications because of the lack of efficient, stable and earth-abundant photoelectrodes. Here, we report simultaneous improvements in carrier separation and light harvesting by constructing p-n heterojunctions in CuO/ZnO nanorod arrays. The novelty of this work is developing a new strategy for preparing a CuO/ZnO p-n heterojunction photoanode for PEC water splitting, in which Cu(OH)2/ZnO is first prepared by a chemical solution strategy and then transformed into CuO/ZnO by annealing. The CuO/ZnO heterojunction photoanode exhibited a significant negative shift of 150 mV for the onset potential and an approximately 4-fold enhancement in the photocurrent at 1.23 V vs reversible hydrogen electrode (RHE) compared with those of pristine ZnO NRs. This work offers a facile strategy for preparing oxide-based p-n heterojunction photoanodes for enhanced PEC water splitting.
关键词: Water Splitting,Light Absorption,Photoelectrochemical (PEC),Heterojunction,Photoanode,P-N Junction
更新于2025-09-23 15:21:21