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Spray coated PbS nano-crystals as an effective counter-electrode material for platinum free Dye-Sensitized Solar Cells (DSSCs)
摘要： This work aims to replace the expansive counter electrode material such as Platinum with low-cost lead sulfide (PbS). Here, lead xanthate was used as a precursor material to synthesize PbS. The precursor material of different concentrations were spray coated on conductive glass substrates and then heated in air at different temperatures and time intervals. The cubical crystals of PbS were formed when heated at 120 °C for 2 h. Field emission scanning electron microscopy (FESEM) and X-ray powder diffraction (XRD) analyses were conducted to substantiate the PbS nanocrystals free of any precursor materials. Cyclic Voltammetry (CV) was performed to inspect the electrochemical performance of PbS crystals. The results found here show that PbS as a catalyst material shows good catalytic activity at the counter electrode of dye-sensitized solar cells (DSSCs). Under optimal conditions, DSSC with PbS shows the power-conversion-efficiency (PCE) of 4.71%, which is slightly lower than that of Pt-based device (5.34%), fabricated under similar conditions.
关键词： Photosensitized,Catalyst,Electrochemical,Photovoltaic,Lead sulfide
更新于2025-09-16 10:30:52
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Curtailing the Overpotential of Lia??CO2 Batteries with Shapea??Controlled Cu2O as Cathode: Effect of Illuminating the Cathode
摘要： Li-air batteries are circumscribed to lab-scale research due to the uninterrupted formation of discharge products. In the case of Li–CO2 batteries, the increase in overpotential due to Li2CO3 formation results in cell death. In this study, we have synthesized Cu2O crystals having three different types of shapes, i.e., cubic, octahedral, and rhombic, to compare the catalytic activity toward CO2 reactions. The full-cycle and long-term stability test reveals that rhombohedral Cu2O facilitates Li2CO3 decomposition more efficiently than that of cubic and octahedral Cu2O. We have extended the cycle to dig into the photocatalytic activeness of the rhombic Cu2O by illuminating the cell. The repeated cycles to 1 h show maximum overpotential of 1.5 V, which is 0.5 V less than that of the cell without illumination. A postmortem analysis of the cell after dividing the cycles into segments demonstrates interesting results on the role of light and Cu2O during the cell cycle.
关键词： Li-CO2 batteries,Shape evolution,Cu2O cathode catalyst,Illumination effect,Charge overpotential
更新于2025-09-16 10:30:52
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Ultra-fast and high flexibility near-infrared photodetectors based on Bi2Se3 nanobelts grown via catalyst-free van der Waals epitaxy
摘要： van der Waals epitaxy (vdWe) method has recently attracted considerable interest due to its extensive application in the growth of layered structure materials. However, the growth process of vdWe is not completely understood. Here, we report the controlled growth process of Bi2Se3 nanobelts and study their photoresponse behaviour. The average length of nanobelts increases from 7 mm to 17 mm by adjusting the temperature of Bi2Se3 powder from 520 (cid:1)C to 530 (cid:1)C, however the average length becomes saturated with further increasing the source material temperature over 530 (cid:1)C. Such a change can be attributed to the competition between the process of Bi2Se3 molecule diffusion and the process of crystal formation-related chemical reaction, leading to a symmetrically studying for the growth process of catalyst-free vdWe growth of Bi2Se3 nanobelts. The photodetectors based on these Bi2Se3 nanobelts show excellent device performance in the near-infrared light range, including an ultra-fast photoresponse (trsing z 37 ms, tdecay z 62 ms), a high responsivity of 10.1 mA/W and a high detectivity of 4.63 (cid:3) 108 Jones. This high device performance could be related to the excellent carrier transport properties as Bi2Se3 nanobelt photodetectors also demonstrate a great potential for fabricating ?exible and wearable electronics by still showing stable photoresponse after bending the device for 200 times.
关键词： 2D NIR photodetectors,Catalyst-free van der Waals epitaxy,Bi2Se3 nanobelts
更新于2025-09-12 10:27:22
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The Growth of Ga2O3 Nanowires on Silicon for Ultraviolet Photodetector
摘要： We investigated the effect of silver catalysts to enhance the growth of Ga2O3 nanowires. The growth of Ga2O3 nanowires on a P+-Si (100) substrate was demonstrated by using a thermal oxidation technique at high temperatures (~1000 °C) in the presence of a thin silver film that serves as a catalyst layer. We present the results of morphological, compositional, and electrical characterization of the Ga2O3 nanowires, including the measurements on photoconductance and transient time. Our results show that highly oriented, dense and long Ga2O3 nanowires can be grown directly on the surface of silicon. The Ga2O3 nanowires, with their inherent n-type characteristics formed a pn heterojunction when grown on silicon. The heterojunction showed rectifying characteristics and excellent UV photoresponse.
关键词： electrical conductivity,nanowires,β-Ga2O3,oxidation,silver catalyst,photodetector
更新于2025-09-12 10:27:22
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Laser-induced continuous generation of Ni nanoparticles for organic synthesis
摘要： The possibilities of laser-induced liquid phase chemical deposition (LCLD) of metal for continuous generation of nickel nanoparticles, the sizes of which allow their use as a catalyst for organic reactions are considered. The conditions for obtaining Ni nanoparticles by this method were optimized.
关键词： laser-induced liquid phase chemical deposition,catalyst,nickel,nanoparticle,laser-induced deposition,solution
更新于2025-09-12 10:27:22
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Architecturing CoTiO3 overlayer on nanosheets-assembled hierarchical TiO2 nanospheres as a highly active and robust catalyst for peroxymonosulfate activation and metronidazole degradation
摘要： Catalytic performance of a heterogeneous cobalt-based catalyst for advanced oxidative process (AOP) correlates tightly with its structure and composition. The main objective of this study is to maximize the utilization and accessibility of cobalt sites while enhancing their activity and stability through rational structural and composition designs, and thus to achieve an excellent performance for heterogeneous peroxymonosulfate (PMS) activation. To this end, a novel CoTiO3/TiO2 composite (CTT), composed of CoTiO3 overlayer on nanosheets-assembled hierarchical TiO2 nanospheres, was elaborately designed and synthesized. The resulting CTT possessed certain features including CoTiO3-rich surface, large surface area (114.8 m2 g?1), and highly open porous channels, which afforded sufficient accessible active sites against undesirable particle agglomeration and shedding. Moreover, cobalt sites of CTT exhibited a higher activity toward PMS than those of Co3O4 due to the composition-induced distinct adsorption nature, easy electron transfer, and strong bond-weakening ability. Benefitting from the unique combination of structural and compositional advantages, CTT manifested remarkable catalytic efficiency, low cobalt leaching (0.078 mg L?1), and excellent reusability in activation of PMS for degradation of the emerging antibiotic pollutant metronidazole (MNZ). The potential degradation pathway for MNZ and the catalytic mechanism were further elucidated. The design strategy proposed in this study may provide a new opportunity for future development of high-performance heterogeneous cobalt-based catalysts in remediation of aquatic environment.
关键词： Heterogeneous cobalt-based catalyst,CoTiO3-rich surface,Metronidazole,Peroxymonosulfate activation,Catalytic degradation,Nanosheets-assembled hierarchical structure
更新于2025-09-12 10:27:22
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A facile approach to synthesis carbon quantum dots-doped P25 visible-light driven photocatalyst with improved NO removal performance
摘要： The water-soluble carbon quantum dots (CQDs) and a novel composite photocatalyst CQDs/P25 have been prepared by a one-step electrochemical-microwave method. The experimental result shows that the photocatalytic degradation of NO by this new kind of CQDs/P25 composite reaches 71%, which is approximately 1.65 times than that of the pure P25 at room temperature. The initial concentration of NO pollutants is 10 ppm. The photocatalytic efficiency of the composite catalyst achieves the highest when the content of CQDs is 1%. It can be concluded that the CQDs extend the light absorption range and adjust the band gap of pure P25. The high photocatalytic performance of this new kind of photocatalyst can be mainly attributed to the unique up-conversion fluorescence property, nanometer size effect and surface activity effect.
关键词： Composite catalyst,NO pollutant,CQDs,P25,Photocatalytic
更新于2025-09-12 10:27:22
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Size dependence of photocatalytic hydrogen generation for CdTe quantum dots
摘要： CdTe quantum dots (QDs) are attractive photosensitizers for photocatalytic proton reduction due to their broad absorbance profile that can extend from the ultraviolet to near-infrared regions, providing access to a larger portion of the solar spectrum than possible with analogous CdSe and CdS QD photosensitizers. Here, the photocatalytic hydrogen (H2) generation from various sizes of dihydrolipoic acid (DHLA)-capped CdTe QDs, ranging from 2.5 to 7.5 nm in diameter, and a molecular Ni-DHLA catalyst in aqueous solutions was evaluated, and an unusual size-dependent photocatalytic activity with CdTe QDs was observed. Under optimized conditions, using 3.4 nm CdTe-DHLA and a 1:20 ratio of QD/Ni-DHLA catalyst, as many as 38 000 turnover numbers (mol H2 per mol QD) were achieved. However, below this critical size, the H2 production efficiency decreased; this behavior is attributed to the rapid oxidation of the QD surface, resulting in detrimental surface trap states. These results are consistent with ultrafast transient absorption spectroscopic measurements, which suggest the presence of extremely fast charge-trapping processes in the oxidized CdTe-DHLA QDs. While fast electron transfer from CdTe-DHLA QDs is observed in the presence of the Ni-DHLA catalyst, the charge trapping processes occur on a competitive time scale, thus lowering the efficiency of the CdTe/Ni-DHLA H2 production system. Understanding rapid charge trapping in CdTe QDs may help suggest potential improvements for the overall CdTe photocatalytic system.
关键词： size dependence,photocatalytic hydrogen generation,Ni-DHLA catalyst,CdTe quantum dots,dihydrolipoic acid
更新于2025-09-12 10:27:22
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Laser Synthesis of Iridium Nanospheres for Overall Water Splitting
摘要： Engineering surface structure of catalysts is an efficient way towards high catalytic performance. Here, we report on the synthesis of regular iridium nanospheres (Ir NSs), with abundant atomic steps prepared by a laser ablation technique. Atomic steps, consisting of one-atom level covering the surface of such Ir NSs, were observed by aberration-corrected high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). The prepared Ir NSs exhibited remarkably enhanced activity both for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in acidic medium. As a bifunctional catalyst for overall water splitting, they achieved a cell voltage of 1.535 V @ 10 mA/cm2, which is much lower than that of Pt/C-Ir/C couple (1.630 V @ 10 mA/cm2).
关键词： overall water splitting,laser ablated nanoparticles,bifunctional catalyst,Ir nanoparticles
更新于2025-09-12 10:27:22
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Synthesis of molecular‐weight‐controlled polyfluorene with boronate at one end
摘要： We investigated the synthesis of poly?uorene with a pinacol boronate (PinB) moiety at one end and with controlled molecular weight by means of Suzuki–Miyaura coupling polymerization of 7-bromo-9,9-dioctyl-9H-?uoren-2-yl boronate (1) with a palladium(0) precatalyst in the presence of pinacol 4-tri?uoromethylphenylboronate (2) as a chain terminator and CsF/18-crown-6 as a base. When we used AmPhos Pd G2, which has a propensity for intramolecular catalyst transfer on a π-electron face, poly?uorene with the PinB moiety at one end and PhCF3 (derived from 2) at the other end was obtained, and the molecular weight increased in proportion to the feed ratio of [1]0/[catalyst]0, though the molecular weight distribution was broad. Since the molecular weight also linearly increased with respect to the conversion of 1 until the middle stage of polymerization, the polymerization appears to involve chain-growth polymerization through intramolecular catalyst transfer from the Pd catalyst inserted into the C Br bond of 1. The broad molecular weight distribution might be mainly due to slow initiation and slow termination with 2, rather than polymer–polymer coupling.
关键词： polymer end,conjugated polymer,Suzuki polycondensation,palladium catalyst,poly?uorene,catalyst-transfer condensation polymerization
更新于2025-09-11 14:15:04