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Enhanced photocatalytic performance of TiO2 NTs decorated with chrysanthemum-like BiOI nanoflowers
摘要： The BiOI nanosheets/chrysanthemum-like nanoflowers were successfully deposited on the surface of TiO2 nanotube arrays (TiO2 NTs) by the successive ionic layer adsorption and reaction (SILAR) method, and the morphology and visible light response of samples with different SILAR deposition cycles were investigated in detail. The as-prepared BiOI/TiO2 NTs significantly enhanced photoelectrocatalytic (PEC) activity for the removal of Methyl orange (MO), Rhodamine B (RhB), Methylene blue (MB) and Cr(VI). The as-prepared Sample-7 with chrysanthemum-like nanostructures showed the high visible light photocurrent density of 120.06 μA/cm2, photovoltage of ?203.61 mV/cm2, PEC efficiencies of 45%, 62%, 79% and 77% for the removal of MO, RhB, MB and Cr(VI), respectively. The high PEC performances could be ascribed to the excellent visible light response and charge carrier transportation in chrysanthemum-like BiOI nanoflowers. By further probing the charge separation and transportation behaviors, the experiments of the energy band structure and active species trapping were carried out. A possible p-n heterojunction photocatalytic mechanism was proposed, which not only benefited the efficient separation of photogenerated electrons but also demonstrated the advanced capacity for the PEC removal of organic dyes and heavy metal ions.
关键词： BiOI,Photoelectrochemical performance,TiO2 nanotube arrays,Nanoflowers
更新于2025-11-19 16:56:35
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Facet effect on the photoelectrochemical performance of a WO3/BiVO4 heterojunction photoanode
摘要： Different WO3 facets have different surface energies and electronic structures, and exhibit different water oxidation abilities and photocatalytic performance as a result. Because of the material’s limited photoresponse region, loading a narrow bandgap material on WO3 is a generally known method for improving photo-harvesting. In this paper, we have synthesized WO3 films with different crystal facet ratios. After loading BiVO4 on these WO3 films, we measured the photoelectrochemical (PEC) performance to investigate the effects of WO3 facet choice on the heterojunction film electrode’s performance. We found that a high-intensity ratio of the (002) WO3 facet in X-ray diffraction (XRD) leads to a more negative onset potential and higher photocurrents in a lower potential region. The ultraviolet photoelectron spectra show a lower work function for the 002-dominant WO3 film compared to other WO3 films, which may result in a higher quasi-fermi level for the heterojunction electrode. Based on the XRD results, the high-intensity ratio of the (002) WO3 facet preferentially exposes the (020) BiVO4 facet, which may be a reason for the better charge extraction observed at low applied potential and high faradic efficiency on PEC water splitting. Together, this results in a high hole injection efficiency for 002-dominant WO3/BiVO4 films compared with WO3/BiVO4 films favoring other WO3 facet ratios.
关键词： BiVO4,WO3,Photoelectrochemical performance,Facet effect,Heterojunction
更新于2025-09-23 15:23:52
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Novel design of photocatalyst coaxial ferromagnetic core and semiconducting shell microwire architecture
摘要： We report a novel design of coaxial core-shell magnetic-semiconductor microwire, as a catalyst under sunlight irradiation. The nano/micro hierarchical architecture-like device is comprised of a coaxial core-shell microwire where the core is the ferromagnetic Fe metal and the shell is formed by a semiconducting hematite layer. The fabrication process of our substrate-free device is simply based on controlled thermal oxidation process revealing a simple and low-cost method. The hematite outer microlayer has a mesoporous structure decorated with nanowires. The ferromagnetic and metallic core assume fundamental importance as to mechanical stability, collect the generated photoelectrons, and to be removed back from the dye solution by a magnetic field gradient or simply a magnet. This nano/micro device has exhibited photocatalytic activity to degrade the methylene blue dye under simulated sunlight irradiation. Additionally, the coaxial magnetic/semiconducting can also be designed as a photoanode to drive water oxidation reaction. The coaxial magnetic/semiconducting photoanode response has shown good chemical stability and long activity under simulated sunlight radiation. In fact, this designed architecture gives novel perspective in the development of substrate free photocatalyst.
关键词： Photoelectrochemical performance,Hematite photoanodes,Photodegradation,Micro/nano architecture,Core-shell microstructures,Thermal oxidation
更新于2025-09-23 15:23:52
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Green Synthesis of Bismuth Sulfide Nanostructures with Tunable Morphologies and Robust Photoelectrochemical Performance
摘要： Manipulating the morphology of chalcogenide semiconductor crystals to tailor their shape- and size-dependent properties is much desired but remains a grand challenge. Herein, we for the first time develop a green, facile and surfactant-free hydrothermal approach for the synthesis of bismuth sulfide (Bi2S3) with highly tunable morphologies in H2WO4 aqueous solution. The H2WO4 is prone to balance the concentration of Bi3+ to S2- in aqueous solution, thus modulating the nucleation and epitaxial growth of Bi2S3. Specifically, in the presence of lower H2WO4 concentration, low number of Bi2S3 nuclei facilitates the preferred growth of nanorod structures along [001] direction, while the Bi-deficient, S-rich conditions in higher H2WO4 concentration give rise to Bi2S3 nanotubes, presumably due to the stronger interlayer interaction and preferred growth in [hk0] direction. The resulting Bi2S3 nanostructures exhibit broad absorption overlapping UV-Visible-NIR regions and red-shifted absorption edges owing to the increased S/Bi molar ratio in Bi2S3 lattices. The Bi2S3 nanorods with higher aspect ratio demonstrate an enhanced photocurrent response by virtue of the improved charge carrier mobility along [001] direction. Different from previous synthetic methodologies, this work details a facile, effective, and environmentally-benign protocol for the synthesis of Bi2S3 nanomaterials in the aqueous medium without any organic reagents. Noteworthy, the excellent and tailorable photoelectrochemical (PEC) performance endows these Bi2S3 nanostructures with vast potential in solar cell and photodetector applications.
关键词： Photoelectrochemical performance,Morphology control,Nanostructures,Green synthesis,Bismuth sulfide
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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Hybrid 0D/2D edamame shaped ZnIn2S4 photoanode modified by Co-Pi and Pt for charge management towards efficient photoelectrochemical water splitting
摘要： Charge separation and transport as well as light absorption are pivotal in determining the efficiency of solar water splitting devices. Herein, we have designed a novel edamame shaped ZnIn2S4 nanostructures consisted of hybridized nanoflakes (2D) and nanoparticles (0D) on ITO conductive substrate through a simple hydrothermal method for PEC water splitting for the first time. The growth mechanism of 0D/2D ZnIn2S4 is proposed and discussed in detail. The series of PEC measurements indicate that edamame shaped 0D/2D ZnIn2S4 films exhibit relatively higher PEC activity (0.37 mA/cm2 at 1.23 V vs. RHE) than that of ZnIn2S4 NFs and ZnIn2S4 NPs due to the enhanced light absorption and efficient charge separation and transfer and increased active sites. Additionally, after selectively depositing Co-Pi cocatalyst and Pt NPs on the top and bottom sides of edamame shaped ZnIn2S4 photoanodes, charge recombination at the surface and interface can be efficiently reduced. The spatial Co-Pi cocatalyst drives holes to flow to the surface, while the Pt NPs facilitate the electrons in the opposite directions. Thus, the integrated Co-Pi/ZnIn2S4/Pt equipment without any additional doping presents an increased photocurrent density with 0.91 mA/cm2 at 1.23 V vs. RHE. This work highlights that edamame shaped ZnIn2S4 can be a promising candidate for photoelectrochemical behavior and rout such as coupling of Co-Pi and Pt co-catalysts on photoanodes have an interfacial electric field can provide a new avenues to design efficient PEC devices in future.
关键词： photoanode,edamame,photoelectrochemical performance,ZnIn2S4,cocatalysts
更新于2025-09-10 09:29:36
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Dramatically enhanced photoelectrochemical properties and transformed p/n type of g-C3N4 caused by K and I co-doping
摘要： Graphitic carbon nitride (g-C3N4) usually shows amphoteric property in a neutral solution. In this work, a K&I co-doped g-C3N4 is prepared by simply sintering the mixture of dicyandiamine, KI and I2. The K&I co-doping modulates the band structure of g-C3N4 with pulling the Fermi level toward its conduction band minimum. The obtained K&I co-doped g-C3N4 (K&I-C3N4) generates positive photocurrents over the whole investigated potential range, exhibiting a typical n-type semiconductor characteristic. Therefore, the K&I co-doping transforms the g-C3N4 from amphoteric to n-type semiconductor. Also, the prepared K&I-C3N4 shows widened light absorption range and enhanced separation efficiency of the photogenerated charge carriers, which results in the dramatically enhanced photoelectrochemical performance.
关键词： Photoelectrochemical performance,K&I co-doping,Fermi level,p/n type,Graphitic carbon nitride
更新于2025-09-10 09:29:36
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Porous graphitic carbon nitride with controllable nitrogen vacancies: As promising catalyst for enhanced degradation of pollutant under visible light
摘要： Carbon nitride (CN) materials are considered as promising photocatalysts due to the advantages of easy availability and visible light absorption. However, wide band gap and high recombination rates of electron-hole pairs of conventional CN materials remain the “bottleneck” of the photocatalysts. Therefore, it is necessary to develop an efficient strategy to narrow band gap of CN and accelerate its charge transfer. In addition, the introduction of nitrogen (N) vacancies is an efficient strategy to narrow band gap and reduce recombination rates of electron-hole pairs. Herein, a novel triazole ring-based graphite carbon nitride (g-C3N5) is developed by one step pathway of NaOH-assisted condensation of triazole rings for the first time. It is found that NaOH can control N vacancies and band gap of g-C3Nx. Meanwhile, the N vacancies of g-C3Nx gradually increase with the increasing concentration of NaOH in the range of 0.005-0.1 g, suppressing the recombination of photogenerated electron-hole pairs. The proposed g-C3Nx exhibits outstanding photocatalytical and photoelectrochemical performance. Therefore, the study highlights the significance of N vacancies in enhancing the photocatalytical and photoelectrochemical performance of promising g-C3N5.
关键词： outstanding photocatalytical and photoelectrochemical performance,g-C3N5,NaOH-treated condensation of triazole rings,controllable N vacancies
更新于2025-09-09 09:28:46
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How does cobalt phosphate modify the structure of TiO2 nanotube array photoanodes for solar water splitting?
摘要： TiO2 nanotube arrays (TNA) have been modified by cobalt phosphate (CoPi) through potentiostatic electrodeposition method. Different samples have been prepared by changing the loaded CoPi through the deposition time from 10 to 960 minutes. Formed catalytic materials have been characterized by different methods. Although charge transfer resistance of the CoPi/TNA photoanodes have been decreased from 5.5 to 4.0 kΩ by increasing the deposition time from 5 to 60 minutes, the maximum photoresponse was obtained for 10 min CoPi deposition leading to 24% more photocurrent compare to bare TNA which proposed optimum value for cobalt phosphate decoration. Based on field emission scanning electron microscopy (FESEM) and X-ray photoelectron spectroscopy (XPS) results, by depositing the electrocatalyst, nanotube walls have been spread and holes have been covered by CoPi. Correlation between observed change in surface morphology and Raman spectra of the samples along with electrocatalytic tests revealed how decoration time can influence structural properties and photoelectrochemical performance of the final CoPi/TNA photoanodes in solar water splitting system.
关键词： CoPi,TiO2 photoanode,photoelectrochemical performance,solar water splitting
更新于2025-09-09 09:28:46
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Construction of Ti3+ self-doped TiO2/BCN heterojunction with enhanced photoelectrochemical performance for water splitting
摘要： Ti3+ self-doped TiO2/BCN heterojunction (Ti3+-TiO2/BCN) was constructed via a hydrothermal method with using NaBH4 as reducing agent. The BCN nanosheets function as a good support to block the agglomeration of Ti3+-TiO2 nanoparticles, which decreased the recombination of photogenerated charge carriers. The Ti3+-TiO2/BCN sample exhibited enhanced electronic conductivity and absorption in visible light region because of the introduction of Ti3+ and oxygen vacancies (Ov). The as-prepared Ti3+-TiO2/BCN sample showed enhanced photoelectrochemical (PEC) performance as confirmed by analyses of LSV, EIS, Bode plots and M–S. Under the visible light irradiation, the optimally Ti3+ self-doped TiO2/BCN heterojunction sample yield a photocurrent density of ～ 0.69 mA/cm2 at 1.23 V versus RHE, which is over three times as high as BCN and TiO2/BCN at the same conditions.
关键词： hydrothermal method,photoelectrochemical performance,NaBH4,water splitting,Ti3+ self-doped TiO2/BCN heterojunction
更新于2025-09-04 15:30:14