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Hexagonal boron nitride quantum dots as a superior hole extractor for efficient charge separation in WO <sub/>3</sub> based photoelectrochemical water oxidation
摘要： Photoelectrochemical (PEC) water splitting is one of the best desirable technique to harvest clean chemical energy from abundant solar energy. However, the anodic half reaction, i.e. water oxidation is complicated due to the involvement of multiple electrons in this process. Herein, stable WO3 nanoblocks with monoclinic phase have been modified by incorporation of hexagonal boron nitride quantum dots (h-BNQDs) to improve the photogenerated electron-hole separation and additionally to hinder the charge recombination process. The photocurrent density (J) value for modified WO3 photoanode by incorporation of BNQDs has been found to be 1.63 mA/cm2 at the potential of 1.23VRHE which is approximately 2.4 fold higher than the bare WO3 photoanode. The enhancement in photocurrent density is mainly due to the hole extraction property of BNQDs on the surface of the WO3 nanoblocks. A two-fold increment in photogenerated charge carrier density (ND) value has been achieved due to better charge separation of electron-hole pairs in the modified system confirmed by the Mott-Schottky (MS) plot. Present work demonstrates a unique, low-cost strategy for enhancement of PEC water oxidation by modification of photoanode with hole extracting agents.
关键词： charge separation,boron nitride quantum dots,photoelectrochemical water oxidation,hole extracting agent,Tungsten trioxide
更新于2025-09-12 10:27:22
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Improving the quality of proton beams via double targets driven by an intense circularly polarized laser pulse
摘要： A new scheme is proposed to improve the quality of proton beams via ultra-intense laser pulse interacting with double plasma targets, which consist of a pre-target with relatively low density and a main target with high density. Both one- and two-dimensional Particle-in-Cell simulations show that, the using of an appropriate pre-target can help to obtain a much stronger longitudinal charge separation field in contrast to using only the main target. And proton beam with lower momentum divergence, better monochromaticity and collimation, as well as higher current density is generated. Moreover, due to the strengthened coupling between the laser pulse and targets, the energy conversion from laser pulse to protons is also increased.
关键词： proton beams,charge separation field,Particle-in-Cell simulations,circularly polarized laser pulse,double targets
更新于2025-09-12 10:27:22
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Carbon‐Intercalated 0D/2D Hybrid of Hematite Quantum Dots/Graphitic Carbon Nitride Nanosheets as Superior Catalyst for Advanced Oxidation
摘要： Efficient charge separation and sufficiently exposed active sites are important for light-driving Fenton catalysts. 0D/2D hybrids, especially quantum dots (QDs)/nanosheets (NSs), offer a better opportunity for improving photo-Fenton activity due to their high charge mobility and more catalytic sites, which is highly desirable but remains a great challenge. Herein, a 0D hematite quantum dots/2D ultrathin g-C3N4 nanosheets hybrid (Fe2O3 QDs/g-C3N4 NS) is developed via a facile chemical reaction and subsequent low-temperature calcination. As expected, the specially designed 0D/2D structure shows remarkable catalytic performance toward the removal of p-nitrophenol. By virtue of large surface area, adequate active sites, and strong interfacial coupling, the 0D Fe2O3 QDs/2D g-C3N4 nanosheets establish efficient charge transport paths by local in-plane carbon species, expediting the separation and transfer of electron/hole pairs. Simultaneously, highly efficient charge mobility can lead to continuous and fast Fe(III)/Fe(II) conversion, promoting a cooperative effect between the photocatalysis and chemical activation of H2O2. The developed carbon-intercalated 0D/2D hybrid provides a new insight in developing heterogeneous catalysis for a large variety of photoelectronic applications, not limited in photo-Fenton catalysis.
关键词： Fe2O3 QDs,g-C3N4 NS,charge separation,carbon-intercalated 0D/2D hybrid,Fe(III)/Fe(II) conversion
更新于2025-09-11 14:15:04
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Improved Charge Separation and Photovoltaic Performance of BiI <sub/>3</sub> Absorber Layers by Use of an In Situ Formed BiSI Interlayer
摘要： Stable and nontoxic bismuth iodide (BiI3) is emerging as a promising absorber material for solar cell applications as it possesses favorable optical properties such as a narrow bandgap (1.7 eV) and a high absorption coe?cient (105 cm?1) in the visible region. Despite these promising features, solar cells employing this material have only achieved power conversion e?ciencies in the region of 1% as of yet, which is distant from the theoretical e?ciency limit of 28%. It is reasonable to suppose that the relatively low performance of BiI3-based solar cells may originate from very short carrier lifetimes (180?240 ps) in BiI3, which makes e?cient separation of mobile charges a crucial factor for the improvement of the photovoltaic performance of this material. Herein, transient optical spectroscopy is employed to show that the use of a bismuth sul?de iodide interlayer between the electron transport layer (ETL) and the bismuth iodide absorber promotes e?cient charge separation. On the basis of this knowledge, we report BiI3 solar cells with a power conversion e?ciency of 1.21% using a solar cell architecture comprised of ITO/SnO2/BiSI/BiI3/organic HTM/Au.
关键词： solar cell,charge separation,transient absorption spectroscopy,BiSI,BiI3
更新于2025-09-11 14:15:04
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Preparation of Nb2O5-decorated hierarchical porous ZnO microspheres with enhanced photocatalytic degradation of palm oil mill effluent
摘要： In the present work, Nb2O5-decorated hierarchical porous ZnO microspheres (ZnO/Nb2O5) were successfully prepared through a facile surfactant-free method. The as-prepared samples were characterized by X-ray diffraction, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, UV–Vis diffuse reflectance spectroscopy, photoluminescence spectroscopy and Brunauer–Emmett–Teller surface area analyses. Under UV light irradiation, the ZnO/Nb2O5 composites degraded palm oil mill effluent (POME) efficiently and demonstrated much higher photocatalytic activity compared to those of pure ZnO and Nb2O5. The enhanced photocatalytic degradation performance of ZnO/Nb2O5 composites was attributed to the high charge separation efficiency and hydroxyl radical generation ability as verified by the photoluminescence spectra. Phytotoxicity test upon the POME degradation over ZnO/Nb2O5 photocatalysis considerably decreased through the measurement of radicle lengths of Vigna radiata. Moreover, the ZnO/Nb2O5 composites were reused several times without appreciable loss of activity. This work revealed that the as-prepared ZnO/Nb2O5 composites have great potential for practical applications in the field of wastewater treatment.
关键词： Nb2O5-decorated hierarchical porous ZnO microspheres,Photocatalytic degradation,Charge separation efficiency,Palm oil mill effluent,Hydroxyl radical generation
更新于2025-09-10 09:29:36
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Confined Preparation of N-doped Commercial P25 TiO2 Photocatalysts with Fast Charge Separation by Argon-diluted Nitrogen Plasma Treatment
摘要： N-doped TiO2 attracts enormous attention due to its cheapness and excellent visible-light-driven photocatalytic activity. An approach assisted by Nitrogen plasma to synthesize the N-doped TiO2 is presented in our work by using commercial available Degussa P25 as raw material. X-ray photoelectron spectroscope (XPS) and transmission electron microscope (TEM) measurement results show that the evidence of N doping and the formation of surface disorder layer, which can both serve as active sites. Electrochemical characterizations verified the excellent photo-generated charge separation feature of the obtained N-doped P25 TiO2. High absorption of visible light, fast charge separation and numerous active sites ensure the excellent photocatalytic activity for the N-doped P25 TiO2 in the photo-oxidation of organic molecules in water. It is noteworthy that the Argon-assistant Nitrogen plasma treatment is superior to conventional pure Nitrogen plasma treatment because of confined Nitrogen ionization. From the results, this plasma treatment method may open up a new way to the application of plasma technology in the activation commercial materials.
关键词： Charge Separation,Transient photocurrents,N-doped TiO2,Plasma Treatment
更新于2025-09-10 09:29:36
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Control of Shell Morphology in p-n Heterostructured Water-Processable Semiconductor Colloids: Toward Extremely Efficient Charge Separation
摘要： This article describes p–n heterostructured water-borne semiconductor nanoparticles (NPs) with unique surface structures via control of shell morphology. The shell particles, comprising PC60–[6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) composite, having n-type semiconductor characteristics, notably influence the charge carrier behavior in the core–shell NPs. A one- or two-phase methodology based on a PC60 surfactant-water phase and PC61BM n-type semiconductor-organic phase provides highly specific control over the shell structure of the NPs, which promote their superior charge separation ability when combined with poly-3-hexyl-thiophene (P3HT). Moreover, the resulting water-borne NP exhibits shell morphology-dependent carrier quenching and stability, which is characterized via luminescence studies paired with structural analysis. Corresponding to the results, outstanding performances of photovoltaic cells with over 5% efficiency are achieved. The results suggest that the surrounding shell environments, such as the shell structure, and its electronic charge density, are crucial in determining the overall activity of the core–shell p–n heterostructured NPs. Thus, this work provides a new protocol in the current fields of water-based organic semiconductor colloids.
关键词： p–n heterostructure,charge separation,water-borne colloids,water-processable nanoparticles,organic semiconducting nanoparticles
更新于2025-09-10 09:29:36
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Improved photoelectric properties of BiOBr nanoplates by co-modifying SnO2 and Ag to promote photoelectrons trapped by adsorbed O2; 通过SnO2和Ag共修饰促进光生电子捕获氧气改善BiOBr纳米盘的光电特性;
摘要： It is highly desired to improve the photoelectric property of nanosized BiOBr by promoting the photogenerated charge transfer and separation. Herein, SnO2 and Ag co-modified BiOBr nanocomposites (Ag-SO-BOB) have been prepared through a simple one-pot hydrothermal method. Surface photovoltage response of BiOBr nanoplates has 4.1-time enhancement after being modified with SnO2 nanoparticles. Transient-state surface photovoltage (TS-SPV) and the atmosphere-controlled steady-state surface photovoltage spectroscopy (AC-SPS) confirmed that this exceptional enhancement of the photovoltage response can be ascribed to the coupled SnO2 acting as platform for accepting the photoelectrons from BiOBr so as to prolong the lifetime and enhance charge separation. Remarkably, the surface photovoltage response can be further enhanced by synchronously introducing Ag nanoparticles, which is up to 15.4-times enhancement compared with bulk BiOBr nanoplates. The enhancement can be attributed to the improved O2 adsorption by introducing Ag to further enhance charge separation. Finally, the synergistic effect of SnO2 and Ag co-modification enhances the surface photovoltage response due to the enhanced charge separation and promoted O2 adsorption, which is also confirmed through photoelectrochemistry and photocatalytic experiment.
关键词： surface photovoltage response,O2 adsorption,charge separation,photoelectron trapping,Ag-SnO2-BiOBr
更新于2025-09-10 09:29:36
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Construction of Novel CdS/SnNb <sub/>2</sub> O <sub/>6</sub> Heterojunctions with Enhanced Photocatalytic Degradation Activity Under Visible Light
摘要： Accelerating the photo-induced charge carrier transfer and improving charge utilization are critical for enhancing the photocatalytic activity of photocatalysts. In this work, we successfully constructed CdS/SnNb2O6 heterojunction photocatalysts by a facile hydrothermal method. The obtained CdS/SnNb2O6 heterojunction exhibited better photocatalytic performance than pristine CdS and SnNb2O6, and the photocatalytic activity of the optimal ratio sample (40 % CdS) was 3.2 and 28.5 times as high as that of the pristine CdS and SnNb2O6, respectively. On the basis of the PL spectra, transient photocurrent response, trapping experiments of the active species, and ESR results, the possible charge carrier transfer and photocatalytic mechanisms of the CdS/SnNb2O6 heterojunction photocatalyst have been illustrated. We demonstrated that the combination of CdS and SnNb2O6 can greatly boost the photo-generated charge carrier separation and therefore enhance the photocatalytic activity. Our work opens up a new insight for development of semiconductor photocatalysts with high efficiency.
关键词： Heterojunctions,Photocatalysis,Charge separation,Reaction mechanisms,Semiconductors
更新于2025-09-10 09:29:36
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Interface engineering of $$\hbox {TiO}_{2}$$TiO2@PANI nanostructures for efficient visible-light activation
摘要： Core–shell-structured TiO2@PANI composites were fabricated using negatively charged titanium glycolate (TG) precursor spheres, which were decorated using hydrochloric acid; subsequently, the uniform polyaniline (PANI) layer could be attached onto the surface of the polystyrene spheres by in situ chemical oxidative polymerization and ?nally, the resulting PANI-grafted TG were allowed to hydrolyse by treating the material with hot water. The TGs were transformed to porous TiO2, leading to the formation of core–shell TiO2@PANI composites. The resulting TiO2@PANI composite photocatalysts were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet–visible diffuse re?ection spectroscopy and photoluminescence spectroscopy. Signi?cantly, the TiO2@PANI composite photocatalysts exhibited dramatically enhanced photo-induced electron–hole separation ef?ciency, which was con?rmed by the results of photocurrent measurements. PANI was dispersed uniformly over the porous TiO2 surface with an intimate electronic contact on the interface to act cooperatively to achieve enhanced photocatalytic properties, indicating that core–shell TiO2@PANI composite photocatalysts could be promising candidate catalysts under visible-light irradiation. The mechanism of enhancing photocatalytic activity was proposed on the basis of the experimental results and estimated energy band positions.
关键词： heterojunction,ef?cient charge separation,Photocatalysis,TiO2-based materials
更新于2025-09-10 09:29:36