- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Rational design of manganese cobalt phosphide with yolk‐shell structure for overall water splitting
摘要： The development of low cost, earth-abundant and efficient catalysts for overall water splitting, involving hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), attracts tremendous attention in recent years. Herein, this work reports the preparation of Mn-Co phosphide (Mn-Co-P) bifunctional catalysts with a yolk-shell structure by a facile hydrothermal route. The as-prepared catalysts exhibit excellent catalytic activity with low overpotentials of 66 mV at 10 mA cm-2 for HER and 355 mV at 50 mA cm-2 for OER in 1 M KOH, along with outstanding stability. More importantly, the cell voltage of 1.74 V can achieve the current density of 10 mA cm-2 when assembled as an electrolyzer for overall water splitting. Such superior performance makes the Mn-Co-P being a promising candidate to replace Pt-based noble metal catalysts for electrocatalytic applications.
关键词： yolk-shell structure,electrochemistry,Mn-Co phosphide,overall water splitting,bifunctional catalyst
更新于2025-11-21 11:01:37
-
A novel bi-functional SiO2@TiO2/CDs nanocomposite with yolk-shell structure as both efficient SERS substrate and photocatalyst
摘要： A novel multi-functional yolk-shell SiO2@TiO2/CDs(y-STCs) nanocomposite with interesting structure of SiO2 cores, porous TiO2 shell, and cavities was synthesized by using a simple method. The experimental results indicate that the yolk-shell structure and modification of carbon dots (CDs) play important roles in the enhancement of SERS signals and photocatalytic performance. The y-STCs nanocomposite used as the SERS substrate showed excellent efficiency and reproducibility for the detection of rhodamine 6G (R6G). The detection limit of R6G was shown to be as low as 6 × 10?8 M. Furthermore, the fabricated y-STCs nanocomposite utilized as the photocatalytst for the degradation of dinitraphenols (DNP) can greatly shorten reaction time to 120 min compared with previous studies, and the DNP degradation rate could reach 96% under simulated sunlight irradiation. The y-STCs nanospheres also possessed excellent cycle stability for the photocatalytic degradation of DNP. Thus, the bi-functional y-STCs nanocomposite may have potential applications in the detection and photocatalytic degradation of organic pollutants.
关键词： SiO2@TiO2/CDs nanocomposite,Yolk-shell structure,SERS detection,Photocatalytic activity
更新于2025-09-23 15:22:29
-
Layer-by-layer assembled synthesis of hollow yolk-shell CdSa??graphene nanocomposites and their high photocatalytic activity and photostability
摘要： Herein, we successfully synthesized, for the first time, a diameter of 340 nm hollow yolk-shell type CdS–graphene composite photocatalyst with a hollow core and an independent void space with 5~10 nm between hollow CdS core and graphene (GR) shell with the thickness of about 2 nm (denoted as hollow CdS@@GR), by the bottom-up method using the template-guided layer-by-layer self-assembly process. The formation mechanism of hollow CdS@@GR nanocomposites was proposed. Due to the unique hollow structure that can absorb more light, more dye, and catalyst molecules and the synergistic effect between hollow CdS core and GR shell with void space, hollow CdS@@GR showed enhanced photocatalytic performance. In addition, GR shell can effectively protect CdS from photocorrosion, and even after five repeated runs, the recycled nanocomposites exhibited superior stability. Moreover, we also proposed the possible photocatalytic mechanism of such nanostructures based on free radical capturing experiments and fluorescent probe technique. The design and fabrication of the hollow yolk-shell structured nanocomposites will provide a new potential route for other stable and efficient photocatalysts to satisfy versatile solar energy conversion.
关键词： Graphene,CdS,Hollow yolk-shell type,Stability,Nanocomposites,Semiconductors
更新于2025-09-23 15:21:01
-
Mechanistic Origin of the High Performance of Yolk@Shell Bi2S3@N-Doped Carbon Nanowire Electrodes
摘要： High-performance lithium-ion batteries are commonly built with the heterogeneous composite electrodes that combine multiple active components for serving various electrochemical and structural functions. Engineering these heterogeneous composite electrodes toward drastically improved battery performance is hinged on a fundamental understanding of the mechanisms of multiple active components and their synergy or tradeoff effects. Herein, we report a rational design, fabrication, and understanding of yolk@shell Bi2S3@N-doped mesoporous carbon (C) composite anode, consisting of a Bi2S3 nanowire (NW) core within a hollow space surrounded by a thin shell of N-doped mesoporous C. This composite anode exhibits desirable rate performance and long cycle stability (700 cycles, 501 mAhg-1 at 1.0 Ag-1, 85% capacity retention). By in-situ transmission electron microscopy (TEM), X-ray diffraction, and NMR experiments and computational modeling, we elucidate the dominant mechanisms of the phase transformation, structural evolution, and lithiation kinetics of the Bi2S3@C NW anode. Our combined in-situ TEM experiments and finite-element simulations reveal that the hollow space between the Bi2S3-NW core and carbon shell can effectively accommodate the lithiation-induced expansion of Bi2S3-NWs without cracking C shells. This work demonstrates an effective strategy of engineering the yolk@shell-architectured anodes and also sheds light onto harnessing the complex multistep reactions in metal sulfides to enable high-performance lithium-ion batteries.
关键词： multiple computational modeling,lithiation mechanism,in-situ experiments,yolk@shell composite anode,lithium-ion battery
更新于2025-09-23 15:21:01
-
The morphology regulation and plasmonic spectral properties of Au@AuAg yolk-shell nanorods with controlled interior gap
摘要： Au@AuAg yolk-shell nanorods with tunable and uniform interior gap were synthesized through galvanic replacement reaction, where Au@Ag core-shell nanorods served as sacrificial templates and HAuCl4 solution served as reductant. The effects of HAuCl4, Ag shell thickness and aspect ratio (AR) of Au nanorods on the morphology of Au@AuAg yolk-shell nanorods had been investigated systemically. The results clearly indicated that AuAg alloy shell thickness of Au@AuAg yolk-shell nanorods could be increased from 3.6 to 10.0 nm by varying the amount of HAuCl4. Meanwhile, the shape of AuAg alloy shell could be tuned by changing the shape of Ag coating. With the increasing of Ag coating thickness, the interior gap could be finely tuned in the range from 2.6 to 8.1 nm. The uniformity of interior gap could be improved by increasing the AR of Au nanorods. All these tunable geometries can further affect the plasmonic spectral properties of Au@AuAg yolk-shell nanorods. Because of the appearance of interior gap, the longitudinal localized surface plasmon resonance (LSPR) peak of Au@AuAg yolk-shell nanorods was located between that of bare Au nanorods and Au@Ag core-shell nanorods without interior gap. The increase of outer AuAg shell thickness can weaken the coupling between the inner and outer surface of the AuAg shell and lead to the decrease of AR, so the transverse and longitudinal LSPR bands gather together. The decrease of Ag coating thickness can enhance the coupling between inner Au nanorod and outer AuAg shell, which results in the red shift of the longitudinal LSPR band. This paper provides a method for studying the plasmonic coupling between two metal surfaces with a metal layer or a dielectric layer, which is also a new approach for regulating the plasmonic spectral properties of bimetallic nanoparticles. The controllability of Au@AuAg yolk-shell nanorods in both the interior gap and outer alloy shells makes them have potential applications in biomedicine, catalysis, nanoreactors, and energy storage.
关键词： interior gap,localized surface plasmon resonance,spectral properties,morphology regulation,Au@AuAg yolk-shell nanorods
更新于2025-09-23 15:21:01
-
From core-shell to yolk-shell: Keeping the intimately contacted interface for plasmonic metal@semiconductor nanorods toward enhanced near-infrared photoelectrochemical performance
摘要： Here we report a synthetic strategy for controllable construction of yolk-shell and core-shell plasmonic metal@semiconductor hybrid nanocrystals through modulating the kinetics of sulfurization reaction followed by cation exchange. The yielded yolk-shell structured products feature exceptional crystallinity and more importantly, the intimately adjoined and sharp interface between plasmonic metal and semiconductor which facilitates efficient charge carrier communications between them. By exploiting the system composed of Au nanorods and p-type PbS as a demonstration, we show that the Au@PbS yolk-shell nanorods manifest notable improvement in visible and near infrared light absorption compared to the Au@PbS core-shell nanorods as well as hollow PbS nanorods. Moreover, the photocathode constituted by Au@PbS yolk-shell nanorods affords the highest photoelectrochemical activities both under simulated sunlight and λ > 700 nm light irradiation. The superior performance of Au@PbS yolk-shell nanorods is considered arising from the combination of the favorable structural advantages of yolk-shell configuration and the surface plasmon resonance enhancement effect. We envision that the reported synthetic strategy can offer a valuable means to create hybrid nanocrystals with desirable structures and functions that enable to harness the photogenerated charge carriers, including the plasmonic hot holes, in wide-range solar-to-fuel conversion.
关键词： solar-to-fuel conversion,cation exchange,surface plasmon resonance,core-shell,yolk-shell
更新于2025-09-23 15:19:57
-
Synthesis of 3D CQDs/urchin-like and yolk-shell TiO2 hierarchical structure with enhanced photocatalytic properties
摘要： A novel CQDs/TiO2 hierarchical structure with enhanced photocatalytic properties was achieved by uniformly decorating urchin-like and yolk-shell TiO2 microspheres (UYTMs) with carbon quantum dots (CQDs) through an environmentally friendly hydrothermal process. The CQDs were ?rstly synthesized by the electrochemical method, and the TEM, Raman and PL characterizations strongly indicated that the as-prepared CQDs exhibited good dispersion, high crystallinity and unique up-conversion properties. The UYTMs synthesized by a NaOH-assisted hydrothermal process showed stable 3D hierarchical structure and large surface area, which was bene?cial for light absorption and contacting with contamination. The good combination of CQDs and UYTMs was further successfully achieved during the hydrothermal process, and demonstrated by a series of tests. The photocatalytic experiments suggested that the CQDs/UYTMs exhibited better photocatalytic activities than the pure UYTMs and P25 under both visible and UV light irradiation. The CQDs/UYTMs combining with 6 wt% of CQDs showed the best photocatalytic e?ciency, while excessive CQDs tended to inhibit the photocatalytic activity. According to the results and discussions, a possible mechanism in improving the photocatalytic e?ciency of the CQDs/UYTMs is signi?cantly proposed. The up-conversion property of CQDs can broaden the absorption spectrum of CQDs/UYTMs to the visible light. Moreover, the CQDs, as the electron reservoirs, are e?cient to separate the electrons and holes, leading to an improved photocatalytic activity of CQDs/UYTMs.
关键词： Carbon quantum dots,Urchin-like microspheres,Photocatalytic activity,TiO2,Yolk shell
更新于2025-09-23 15:19:57
-
Yolk-shell SnO2@TiO2 nanospheres as electron transport layer in mesoscopic perovskite solar cell
摘要： SnO2 nanoparticles were synthesized and modified by TiO2 shell through sol–gel method. Band gap energy and photoluminescence properties of SnO2 nanoparticles and yolk-shell SnO2@TiO2 nanospheres were investigated by UV–Vis absorption spectra and photoluminescence (PL) spectroscopy. The nanoparticles were used as electron transport layers (ETLs) for fabrication of perovskite solar cells (PSCs) and PSC based on yolk-shell SnO2@TiO2 ETL showed higher photon conversion efficiency (PCE = 11.28%) and lower hysteresis index (37%) compared with the PSC made of SnO2 ETL (PCE = 8.55% and hysteresis index = 52%). The increase in the short-circuit current density (Jsc), open circuit voltage (Voc), and subsequently PCE for the PSC based on yolk-shell SnO2@TiO2 ETL is attributed to the smoothness and uniformity of perovskite film, improvement of surface defects at the ETL/perovskite interface, and suitable energy band alignment for effective injection of electron from perovskite to the conduction band of TiO2 as well as from TiO2 to the SnO2. Electrochemical impedance spectroscopy (EIS) was employed to determine the charge transport resistance at the ETL/perovskite interface and confirmed the results obtained by the characteristic curve of the current density–voltage. The stability test of the devices displayed that long-term stability of PSC made of yolk-shell SnO2@TiO2 ETL is almost the same as the SnO2 ETL-based PSC because of the high resistance of SnO2 against the moisture and oxygen in the environment.
关键词： Yolk-shell SnO2@TiO2 nanospheres,Long-term stability,Perovskite solar cell,Photon conversion efficiency,Electron transport layer
更新于2025-09-16 10:30:52
-
N-doped C/CoSe2@Co–FeSe2 yolk-shell nano polyhedron as superior counter electrode catalyst for high-efficiency Pt-free dye-sensitized solar cell
摘要： Yolk-shell structures based on transition metal chalcogenides (TMCs) have broad application prospects in energy conversion/storage fields. In this work, a facile step-wise synthetic strategy was used to synthesize the yolk-shell structured polyhedrons. The intermediate named as ZIF-67@Co-Fe PBA nanocrystal was formed by the reaction between Co2+ released from ZIF-67 polyhedrons and [Fe(CN)6]3? hydrolyzed from K3[Fe(CN)6]. N-doped carbon/CoSe2@Co-FeSe2 (CoSe2-NC@Co-FeSe2) and N-doped carbon/CoS2@Co-FeS2 (CoS2-NC@Co-FeS2) polyhedrons with yolk-shell structures were prepared by modifying the ZIF-67@Co-Fe PBA nanocrystals in the annealing process and they have been applied in dye-sensitized solar cells (DSSCs). Noteworthily, CoSe2-NC@Co-FeSe2 and CoS2-NC@Co-FeS2 yolk-shell polyhedrons showed high catalytic activity in accelerating the reduction of triiodide in DSSCs because of the distinctive structural characteristics and favorable chemical compositions. The power conversion efficiency (PCE) of 9.61% and 9.18% were obtained by CoSe2-NC@Co-FeSe2 and CoS2-NC@Co-FeS2 based DSSCs, respectively, which were both superior to that of Pt (8.15%). This as-designed approach implies the new perspective to prepare more types of TMCs with yolk-shell structures in multitudinous areas of energy conversion.
关键词： CoSe2-NC@Co-FeSe2,Transition metal selenides,Yolk-shell polyhedrons,CoS2-NC@Co-FeS2,Dye-sensitized solar cells
更新于2025-09-11 14:15:04
-
Synthesis of Urchin-like and Yolk-shell TiO <sub/>2</sub> microspheres with enhanced photocatalytic properties
摘要： The novel urchin-like and yolk-shell titania microspheres (henceforth called UYTMs) with nanowires/microspheres hierarchical structures were successfully synthesized by a synthetic sol-gel and hydrothermal method without using any template. Uniform TiO2 microspheres were firstly prepared by the sol-gel method, and the great monodispersed properties was delicately regulated by using the surfactant of KCl, aniline and a proper amount of water. The urchin-like yolk-shell morphology was further achieved by a NaOH-assisted hydrothermal process, and the diameter and shell thickness of the UYTMs were highly controlled by the concentration of NaOH. The detailed morphology, chemical composition and crystallinity of the UYTMs were systematically characterized by several techniques, and the underlying formation mechanisms was attentively discussed as well. The photodegradation of methylthionine chloride experiments indicated the UYTMs showed much better photocatalytic activity than that of commercial P25. This is mainly because the UYTMs exhibited much more reactive sites, higher adsorption ability and tuned optical absorption behavior owing to their large specific surface area, hierarchical structures and the special hollow yolk-shell structure.
关键词： Titania,NaOH-assisted hydrothermal synthesis,Photocatalytic activity,Yolk-shell,Urchin-like microspheres
更新于2025-09-10 09:29:36