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1.
Small ; 20(9): e2305906, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-37857591

RESUMEN

Replacing traditional oxygen evoltion reaction (OER) with biomass oxidation reaction (BOR) is an advantageous alternative choice to obtain green hydrogen energy from electrocatalytic water splitting. Herein, a novel of extremely homogeneous Ni3 S2 nanosheets covered TiO2 nanorod arrays are in situ growth on conductive Ni foam (Ni/TiO2 @Ni3 S2 ). The Ni/TiO2 @Ni3 S2 electrode exhibits excellent electrocatalytic activity and long-term stability for both BOR and hydrogen evolution reaction (HER). Especially, taking glucose as a typical biomass, the average hydrogen production rate of the HER-glucose oxidation reaction (GOR) two-electrode system reached 984.74 µmol h-1 , about 2.7 times higher than that of in a common HER//OER two-electrode water splitting system (365.50 µmol h-1 ). The calculated power energy saving efficiency of the GOR//HER system is about 13% less than that of the OER//HER system. Meanwhile, the corresponding selectivity of the value-added formic acid produced by GOR reaches about 80%. Moreover, the Ni/TiO2 @Ni3 S2 electrode also exhibits excellent electrocatalytic activity on a diverse range of typical biomass intermediates, such as urea, sucrose, fructose, furfuryl alcohol (FFA), 5-hydroxymethylfurfural (HMF), and alcohol (EtOH). These results show that Ni/TiO2 @Ni3 S2 has great potential in electrocatalysis, especially in replacing OER reaction with BOR reaction and promoting the sustainable development of hydrogen production.

2.
Angew Chem Int Ed Engl ; 63(22): e202403022, 2024 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-38485698

RESUMEN

Integrating solar energy into rechargeable battery systems represents a significant advancement towards sustainable energy storage solutions. Herein, we propose a win-win solution to reduce the shuttle effect of polysulfide and improve the photocorrosion stability of CdS, thereby enhancing the energy conversion efficiency of rGO/CdS-based photorechargeable integrated lithium-sulfur batteries (PRLSBs). Experimental results show that CdS can effectively anchor polysulfide under sunlight irradiation for 20 minutes. Under a high current density (1 C), the discharge-specific capacity of the PRLSBs increased to 971.30 mAh g-1, which is 113.3 % enhancement compared to that of under dark condition (857.49 mAh g-1). Remarkably, without an electrical power supply, the PRLSBs can maintain a 21 hours discharge process following merely 1.5 hours of light irradiation, achieving a breakthrough solar-to-electrical energy conversion efficiency of up to 5.04 %. Ex situ X-ray photoelectron spectroscopy (XPS) and in situ Raman analysis corroborate the effectiveness of this complementary weakness approach in bolstering redox kinetics and curtailing polysulfide dissolution in PRLSBs. This work showcases a feasible strategy to develop PRLSBs with potential dual-functional metal sulfide photoelectrodes, which will be of great interest in future-oriented off-grid photocell systems.

3.
Small ; 19(17): e2207413, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36720802

RESUMEN

The unremitting exploration of well-architectured and high-efficiency oxygen electrocatalysts is promising to speed up the surface-mediated oxygen reduction/evolution reaction (ORR/OER) kinetics of rechargeable zinc-air batteries (ZABs). Herein, bimetallic CoCu-codecorated carbon nanosheet arrays (CoCu/N-CNS) are proposed as self-supported bifunctional oxygen catalysts. The integrated catalysts are in situ constructed via a simple sacrificial-templated strategy, imparting CoCu/N-CNS with 3D interconnected conductive pathways, abundant mesopores for electrolyte penetration and ion diffusion, as well as Cu-synergized Co-Nx /O reactive sites for improved catalytic activities. By incorporating a moderate amount of Cu into CoCu/N-CNS, the bifunctional activities can be further increased due to synergistic oxygen electrocatalysis. Consequently, the optimized CoCu/N-CNS realizes a low overall overpotential of 0.64 V for OER and ORR and leads to high-performance liquid ZABs with high gravimetric energy (879.7 Wh kg-1 ), high peak power density (104.3 mW cm-2 ), and remarkable cyclic stability upon 400 h/1000 cycles at 10 mA cm-2 . More impressively, all-solid-state flexible ZABs assembled with the CoCu/N-CNS cathode exhibit superior rate performance and exceptional mechanical flexibility under arbitrary bending conditions. This CoCu/N-CNS monolith holds significant potential in advancing cation-modulated multimetallic electrocatalysts and multifunctional nanocatalysts.

4.
J Am Chem Soc ; 143(12): 4790-4800, 2021 Mar 31.
Artículo en Inglés | MEDLINE | ID: mdl-33734670

RESUMEN

Low loading is one of the bottlenecks limiting the performance of quantum dot sensitized solar cells (QDSCs). Although previous QD secondary deposition relying on electrostatic interaction can improve QD loading, due to the introduction of new recombination centers, it is not capable of enhancing the photovoltage and fill factor. Herein, without the introduction of new recombination centers, a convenient QD secondary deposition approach is developed by creating new adsorption sites via the formation of a metal oxyhydroxide layer around QD presensitized photoanodes. MgCl2 solution treated Zn-Cu-In-S-Se (ZCISSe) QD sensitized TiO2 film electrodes have been chosen as a model device to investigate this secondary deposition approach. The experimental results demonstrate that additional 38% of the QDs are immobilized on the photoanode as a single layer. Due to the increased QD loading and concomitant enhanced light-harvesting capacity and reduced charge recombination, not only photocurrent but also photovoltage and fill factor have been remarkably enhanced. The average PCE of resulted ZCISSe QDSCs is boosted to 15.31% (Jsc = 26.52 mA cm-2, Voc = 0.802 V, FF = 0.720), from the original 13.54% (Jsc = 24.23 mA cm-2, Voc = 0.789 V, FF = 0.708). Furthermore, a new certified PCE record of 15.20% has been obtained for liquid-junction QDSCs.

5.
Angew Chem Int Ed Engl ; 60(2): 660-665, 2021 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-32964638

RESUMEN

Lead-free CsSnX3 perovskite NCs are becoming a promising alternative to CsPbX3 (X=Cl, Br, I), but suffer from extremely poor stability. Herein, we highlight the significant effect of SnII precursors used in the synthesis on the stability of the resultant CsSnX3 NCs. A method is proposed for synthesizing CsSnX3 NCs using Cs2 CO3 , SnC2 O4 , and NH4 X as corresponding constituent precursors, wherein the ratio of reactants can be easily adjusted. Stable CsSnX3 NCs can be obtained with the use of antioxidative SnC2 O4 as the SnII precursor. Experimental results show that the improvement of NCs stability is mainly ascribed to the role of oxalate in the SnC2 O4 precursor. Oxalate ion has a strong antioxidative ability and can effectively inhibit the oxidation of SnII during the synthesis. Besides, oxalate as a bidentate capping ligand is shown to be coordinated on the surface of formed NCs. This can not only passivate the uncoordinated Sn on the surface but also prevent the oxidation of the NCs.

6.
J Nanosci Nanotechnol ; 15(7): 4870-6, 2015 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-26373049

RESUMEN

The efficient visible-light active nanocomposites of {001} facets-exposed TiO2-reduced graphene oxide (RGO) were fabricated by a simple one-step solvothermal approach for application in photocatalytic degradation. The morphology, structure and optical properties of the nanocomposites were well characterized by X-ray diffraction, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy. The results indicated that the TiO2 nanoflakes with exposed {001} facets were well-dispersed and contact closely with the surface of graphene sheets via the formation of Ti-O-C bonds. The percentage of the {001} facets which have higher chemistry activity in anatase TiO2 was about 71.3%. The incorporation of RGO with TiO2 increased the light absorption in the whole visible region and displayed a red-shift absorption edge, accelerated the separation of photogenerated electron-hole pairs, furthermore, effectively enhanced the photocatalytic activity of TiO2 under the visible light. The efficiency of the system was significantly influenced by the content of RGO. The optimum content of RGO was 5 wt% for the maximum photocatalytic efficiency.


Asunto(s)
Grafito/química , Luz , Azul de Metileno/química , Nanocompuestos/química , Procesos Fotoquímicos , Titanio/química , Catálisis , Nanocompuestos/ultraestructura
7.
Nanotechnology ; 25(13): 135403, 2014 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-24598127

RESUMEN

Unique SnO(x) (x = 1,2)/ordered mesoporous carbon nanocomposites (denoted as SnO(x)/OMC) are firstly synthesized through a 'one-pot' synthesis together with the soft template self-assembly approach. The obtained SnO(x)/OMC nanocomposites with various SnO(x) contents exhibit uniform pore sizes between 3.9 and 4.2 nm, high specific surface areas between 497 and 595 m(2) g(-1), and high pore volumes between 0.39 and 0.48 cm(3) g(-1). With loading of Pt, Pt-SnO(x)/OMC with relatively low SnO(x) content exhibits superior electrocatalytic performance, long-term durability, and resistance to CO poisoning for methanol oxidation, as compared to Pt/OMC, PtRu/C and Pt-SnO(x)/C, which may be attributed not only to the synergetic effect of embedded SnO(x), but also to the highly ordered mesostructure with high specific surface areas and large pore volumes affording plenty of surface area for support of Pt nanoparticles. This work supplies an efficient way to synthesize novel ordered mesoporous carbon self-supported metallic oxide as catalyst support and its further potential application to reduce the cost of catalysts in direct methanol fuel cells.

8.
Bioresour Technol ; 400: 130684, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38614146

RESUMEN

Advancements in biochar activating persulfate advanced oxidation processes (PS-AOP), have gained significant attention. However, the understanding of biochar-based catalysts in activating PS remains limited. Herein, biochar (BC) and N-doped biochar (NBC) were synthesized from hemp for activating PS to treat tetracycline (TC) wastewater and analyzed their mechanisms separately. Surprisingly, N-doped in biochar leads to a change in the activation mechanism of PS. The BC-PS system operates mainly through a radical pathway, advantageous for treating soil organic pollution (68%) with pH adaptability (less than 10% variation). Nevertheless, the NBC-PS system primarily employs an electron transfer non-radical pathway, demonstrating stability (only 7% performance degradation over four cycles) and enhanced resistance to anionic interference (less than 10% variation) in organic wastewater treatment. This study provides a technical reference and theoretical foundation for enhancing biochar activation of PS in the removal of organic pollutants from aquatic and terrestrial environments.


Asunto(s)
Cannabis , Carbón Orgánico , Sulfatos , Tetraciclina , Aguas Residuales , Contaminantes Químicos del Agua , Purificación del Agua , Carbón Orgánico/química , Aguas Residuales/química , Tetraciclina/química , Cannabis/química , Sulfatos/química , Contaminantes Químicos del Agua/química , Catálisis , Purificación del Agua/métodos , Oxidación-Reducción , Concentración de Iones de Hidrógeno
9.
Adv Mater ; 36(24): e2313513, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38461147

RESUMEN

The development of high-density and closely spaced frustrated Lewis pairs (FLPs) is crucial for enhancing catalyst activity and accelerating reaction rates. However, constructing efficient FLPs by breaking classical Lewis bonds poses a significant challenge. Here, this work has made a pivotal discovery regarding the Jahn-Teller effect during the formation of grain boundaries in carbon-encapsulated Ni/NiOx (Ni/NiOx@C). This effect facilitates the formation of high-density O (VO) and Ni (VNi) vacancy sites with different charge polarities, specifically FLP-VO-C basic sites and FLP-VNi-C acidic sites. The synergistic interaction between FLP-VO-C and FLP-VNi-C sites not only reduces energy barriers for water adsorption and splitting, but also induces a strong photothermal effect. This mutually reinforcing effect contributes to the exceptional performance of Ni/NiOx@C as a cocatalyst in photothermal-assisted photocatalytic hydrogen production. Notably, the Ni/NiOx@C/g-C3N4 (NOCC) composite photocatalyst exhibits remarkable hydrogen production activity with a rate of 10.7 mmol g-1 h-1, surpassing that of the Pt cocatalyst by 1.76 times. Moreover, the NOCC achieves an impressive apparent quantum yield of 40.78% at a wavelength of 380 nm. This work paves the way for designing novel defect-state multiphase cocatalysts with high-density and adjacent FLP sites, which hold promise for enhancing various catalytic reactions.

10.
Langmuir ; 29(49): 15433-41, 2013 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-24256401

RESUMEN

Magnetic nanoparticle clusters (MNCs) are a class of secondary structural materials that comprise chemically defined nanoparticles assembled into clusters of defined size. Herein, MNCs are fabricated through a one-pot solvothermal reaction featuring self-limiting assembly of building blocks and the controlled reorganization process. Such growth-dissolution-regrowth fabrication mechanism overcomes some limitations of conventional solvothermal fabrication methods with regard to restricted available feature size and structural complexity, which can be extended to other oxides (as long as one can be chelated by EDTA-2Na). Based on this method, the nanoparticle size of MNCs is tuned between 6.8 and 31.2 nm at a fixed cluster diameter of 120 nm, wherein the critical size for superparamagnetic-ferromagnetic transition is estimated from 13.5 to 15.7 nm. Control over the nature and secondary structure of MNCs gives an excellent model system to understand the nanoparticle size-dependent magnetic properties of MNCs. MNCs have potential applications in many different areas, while this work evaluates their cytotoxicity and Pb(2+) adsorption capacity as initial application study.


Asunto(s)
Nanopartículas de Magnetita/química , Compuestos Férricos/química , Nanopartículas/química
11.
J Nanosci Nanotechnol ; 13(1): 91-7, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23646702

RESUMEN

The enrofloxacin hydrochloride (Enro), an anti-inflammatory drug for the animals, was loaded on the TNTs through physical absorption due to the high specific surface area and excellent surface activity of the TiO2 nanotubes. The samples were characterized by XRD, BET, TEM, TG and FTIR. The in vitro controlled release behavior at different temperatures was studied in detail. The results showed that the obtained TNTs were uniform and mainly amorphous crystal phase with a diameter of 10-15 nm and a length of 350-400 nm. By investigating the effect of the hydrothermal reaction process of the obtained TiO2 nanotubes and the drug loading frequency on the loading content of Enro drugs, the results indicated that the increasing loading frequency of the drug was available for the drug loading and the maximum loading content of drug reached to 33.28%. Enro-TNTs performed a better release profile at low temperature than at high temperature in PBS solution. The Higuchi square root models are suitable to explain the in vitro drug release behavior of Enro from Enro-TNTs.


Asunto(s)
Preparaciones de Acción Retardada/química , Fluoroquinolonas/química , Nanocápsulas/química , Nanocápsulas/ultraestructura , Nanotubos/química , Nanotubos/ultraestructura , Titanio/química , Absorción , Difusión , Enrofloxacina , Fluoroquinolonas/administración & dosificación , Ensayo de Materiales , Tamaño de la Partícula , Propiedades de Superficie
12.
J Nanosci Nanotechnol ; 12(11): 8391-5, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-23421220

RESUMEN

Ag/TiO2 nanotubes with uniform distribution were successfully prepared by a hydrothermal-dipping method. The synthesized samples were characterized by XRD, TEM and FTIR, respectively. The results exhibited that the morphological structure of the TiO2 nanotubes was improved by the doping of Ag ions. The photocatalytic degradation experiment indicated that the photocatalytic activity of the Ag/TiO2 nanotubes indicated better photocatalytic activity than pure TiO2 nanotubes since silver was able to help the electron-hole separation by attracting photoelectrons. The optimal mol ration of TiO2 and AgNO3 was 25:1.


Asunto(s)
Nanotubos/química , Nanotubos/ultraestructura , Fotoquímica/métodos , Plata/química , Titanio/química , Catálisis , Iones , Luz , Sustancias Macromoleculares/química , Sustancias Macromoleculares/efectos de la radiación , Ensayo de Materiales , Conformación Molecular/efectos de la radiación , Nanotubos/efectos de la radiación , Tamaño de la Partícula , Plata/efectos de la radiación , Propiedades de Superficie/efectos de la radiación , Titanio/efectos de la radiación
13.
Nanomaterials (Basel) ; 12(3)2022 Feb 06.
Artículo en Inglés | MEDLINE | ID: mdl-35159906

RESUMEN

Formic acid is an appealing hydrogen storage material. In order to rapidly produce hydrogen from formic acid under relatively mild conditions, high-efficiency and stable photocatalytic systems are of great significance to prompt hydrogen (H2) evolution from formic acid. In this paper, an efficient and stable photocatalytic system (CdS/P/MoS2) for H2 production from formic acid is successfully constructed by elemental P doping of CdS nanorods combining with in situ photodeposition of MoS2. In this system, P doping reduces the band gap of CdS for enhanced light absorption, as well as promoting the separation of photogenerated charge carriers. More importantly, MoS2 nanoparticles decorated on P-doped CdS nanorods can play as noble-metal-free cocatalysts, which increase the light adsorption, facilitate the charge transfer and effectively accelerate the hydrogen evolution reaction. Consequently, the apparent quantum efficiency (AQE) of the designed CdS/P/MoS2 is up to 6.39% at 420 nm, while the H2 evolution rate is boosted to 68.89 mmol·g-1·h-1, which is 10 times higher than that of pristine CdS. This study could provide an alternative strategy for the development of competitive CdS-based photocatalysts as well as noble-metal-free photocatalytic systems toward efficient hydrogen production.

14.
J Colloid Interface Sci ; 619: 188-197, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35395537

RESUMEN

The persistence and wide dispersion of antibiotics have a severe impact on the ecological environment. Developing an effective method with universal applicability to remove pollutants is pretty necessary. Herein, a bimetallic oxides (Co3V2O8) heterogeneous material was successfully prepared and used to activate the persulfate (PS) for purification of tetracycline (TC) wastewater. By exploring the reaction conditions and influencing factors, the removal rate of 50 mg⋅L-1 TC reached 87.1% by Co3V2O8/PS system, and the reaction rate constant was up to 0.0271 min-1. As a highly efficient catalyst for the activation of PS, Co3V2O8/PS system produces radicals of SO4•-, •OH, •O2- and 1O2 in the reaction process due to the Co(II) and V(IV) exchange electrons with S2O82- and O2. Simultaneously, the internal electron exchange occurs between Co(II)/Co(III) and V(IV)/V(V), which stabilizes the content of Co(II) and V(IV). This work provides a novel activator for PS activation to degrade contaminants and contributes to a better understanding of the PS activation mechanism by transition compound.


Asunto(s)
Tetraciclina , Contaminantes Químicos del Agua , Antibacterianos , Óxidos , Tetraciclina/análisis , Aguas Residuales , Contaminantes Químicos del Agua/análisis
15.
ACS Appl Mater Interfaces ; 13(26): 30746-30755, 2021 Jul 07.
Artículo en Inglés | MEDLINE | ID: mdl-34170655

RESUMEN

Lithium-sulfur batteries (LSBs) have been considered as potential next-generation energy storage systems due to their high specific energy of 2600 Wh kg-1 and 2800 Wh L-1. Nevertheless, the practical application of LSBs still faces several hazards, including the shuttle effect of soluble lithium polysulfides, low electrical conductivities of solid sulfur and lithium sulfides, and large volume expansion during charge/discharge cycles. To address this critical challenge, we innovatively proposed facile synthesis of nanostructured VN quantum dots (VNQD)/holey graphene matrix for stabilizing the sulfur cathode by simultaneously promoting the trapping, anchoring, and catalyzing efficiencies of both LiPSs and Li2S. Benefiting from abundant edge catalytic sites of VNQD, in-plane nanopores of graphene, and high electrical conductivity, the sulfur host not only provides high adsorption capability toward soluble polysulfides, strong binding ability for anchoring solid Li2S, and their rapid conversion kinetics but also contributes abundant sulfur storage sites and efficient transport pathways for lithium ions (Li+) and electrons. Consequently, the sulfur cathode exhibits high initial capacities of 1320 mAh g-1, high rate capability (850 mAh g-1 @ 4 mA cm-2), and high capacity retention of 99.95% per cycle after 500 cycles, providing a feasible solution for the practical utilization of shuttle-free Li-S batteries.

16.
ACS Appl Mater Interfaces ; 13(31): 37299-37307, 2021 Aug 11.
Artículo en Inglés | MEDLINE | ID: mdl-34324293

RESUMEN

A copper (Cu) material is catalytically active for formaldehyde (HCHO) dehydrogenation to produce H2, but the unsatisfactory efficiency and easy corrosion hinder its practical application. Alloying with other metals and coating a carbon layer outside are recognized as effective strategies to improve the catalytic activity and the long-term durability of nonprecious metal catalysts. Here, highly dispersed CuNi alloy-carbon layer core-shell nanoparticles (CuNi@C) have been developed as a robust catalyst for efficient H2 generation from HCHO aqueous solution at room temperature. Under the optimized reaction conditions, the CuNi@C catalyst exhibits a H2 evolution rate of 110.98 mmol·h-1·g-1, which is 1.5 and 4.9 times higher than those of Cu@C and Ni@C, respectively, which ranks top among the reported nonprecious metal catalysts for catalytic HCHO reforming at room temperature to date. Furthermore, CuNi@C also displays excellent stability toward the catalytic HCHO reforming into H2 in tap water owing to the well-constructed carbon sheath protecting CuNi nanocrystals from oxidation in an alkaline medium. Combined with density functional theory calculations, the superior catalytic efficiency of CuNi@C for H2 generation results from the synergistic contribution between the massive active species from HCHO decomposition on the Cu sites and the remarkable H2 evolution activity on Ni sites. The improved performance of CuNi@C highlights the enormous potential of advancing noble-metal-free nanoalloys as cost-effective and recyclable catalysts for energy recovery from industrial HCHO wastewater.

17.
Small Methods ; 5(11): e2100878, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-34927978

RESUMEN

The rational design and construction of cost-effective nickel-based phosphide or sulfide (photo)electrocatalysts for hydrogen production from water splitting has sparked a huge investigation surge in recent years. Whereas, nickel phosphides (Nix Py ) possess more than ten stoichiometric compositions with different crystalline. Constructing Nix Py with well crystalline and revealing their intrinsic catalytic mechanism at atomic/molecular levels remains a great challenge. Herein, an easy-to-follow phase-controllable phosphating strategy is first proposed to prepare well crystalline Nix Py (Ni3 P and Ni12 P5 ) modified CdS@Ni3 S2 heterojunction electrocatalysts. It is found that Ni3 P modified CdS@Ni3 S2 (CdS@Ni3 S2 /Ni3 P) exhibits remarkable stability and bifunctional electrocatalytic activities in both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Density functional theory results suggest that P-Ni sites and P sites in CdS@Ni3 S2 /Ni3 P, respectively, serve as OER and HER active sites during electrocatalytic water splitting processes. Moreover, benefiting from the advantageous photocatalyst@electrocatalyst core@shell structure, CdS@Ni3 S2 /Ni3 P delivers an advantaged photoassisted electrocatalytic water splitting property. The champion electrical to hydrogen and solar to hydrogen energy conversion efficiencies of CdS@Ni3 S2 /Ni3 P, respectively, reach 93.35% and 4.65%. This work will provide a general guidance for synergistically using solar energy and electric energy for large-scale H2 production from water splitting.

18.
Chemistry ; 16(29): 8757-61, 2010 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-20572173

RESUMEN

Hierarchical ZnO hollow spheres (400-500 nm in diameter) consisting of ZnO nanoparticles with a diameter of approximately 15 nm have been successfully prepared by a facile and rapid sonochemical process. The formation of hierarchical ZnO hollow spheres is attributed to the oriented attachment and subsequent Ostwald ripening process according to time-dependent experiments. The as-prepared ZnO hollow spheres are used as a photoanode in dye-sensitized solar cells and exhibit a highly efficient power conversion efficiency of 4.33%, with a short-circuit current density of 9.56 mA cm(-2), an open-circuit voltage of 730 mV, and a fill factor of 0.62 under AM 1.5 G one sun (100 mW cm(-2)) illumination. Moreover, the photovoltaic performance (4.33%) using the hierarchical ZnO hollow spheres is 38.8% better than that of a ZnO nanoparticle photoelectrode (3.12%), which is mainly attributed to the efficient light scattering for the former.


Asunto(s)
Suministros de Energía Eléctrica , Nanoestructuras/química , Energía Solar , Óxido de Zinc/química , Óxido de Zinc/síntesis química , Colorantes/química , Microscopía Electrónica de Rastreo , Fotoquímica
19.
J Nanosci Nanotechnol ; 10(8): 5099-105, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21125856

RESUMEN

We report on a study on the development of a self-supported membrane of carbon nanotube (CNT) mixed with MnO2 nanowires as supercapacitors. Both single-walled CNTs (SWCNTs) and multiwalled CNTs (MWCNTs) have been explored to serve as the electrically conductive networks to connect redox active MnO2 nanowires. High-quality alpha-MnO2 nanowires were synthesized using bulk alpha-MnO2 crystals as the precursor by a facile hydrothermal method. The morphology and structure of the as-prepared alpha-MnO2 nanowires were characterized by X-ray and electron diffraction, transmission electron microscopy, and scanning electron microscopy. Supercapacitor membranes were prepared by filtration of mixture solutions of MnO2 nanowires and CNTs at various ratios, forming entangled networks which are self-supported and directly used as supercapacitor electrodes without binders or backing metals. Cyclic voltammetry at various scan rates and charge--discharging measurements are used to characterize the supercapacitance of the CNT-MnO2 nanowire membranes. The specific capacitance has been found to be increased by several times over that of pure CNT membranes after incorporation of MnO2 nanowires.

20.
ACS Appl Mater Interfaces ; 12(39): 43844-43853, 2020 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-32897698

RESUMEN

Lithium-sulfur (Li-S) batteries have shown great potential in the next-generation energy storage devices due to high theoretical energy density and low cost. To obtain high-performance Li-S batteries, it is important to inhibit the polysulfide shuttle effect and improve the reaction kinetics of polysulfides. Herein, CoP nanoparticles coated by metal-organic framework-derived N-doped mesoporous carbon (CoP@N-C) composites are synthesized and applied in both a cathode for a sulfur host and a modified layer on a separator for high-energy-density Li-S batteries since the CoP component has strong chemical anchoring capability toward soluble polysulfides and high electrochemical activity toward polysulfides transformation. Meanwhile, the porous structure of conductive N-doped mesoporous carbon can not only buffer the volume variation of sulfur during the charge/discharge process but also enhance the charge transport rate in the cathode. The constructed batteries have demonstrated a high specific capacity of 1222 mAh g-1 (8.6 mAh cm-2) with a high sulfur areal loading of ∼7.0 mg cm-2 on cathodes, and a mass loading of 0.35 mg cm-2 for modified layer on separators. Its average capacity decay is only 0.076% per cycle after 100 cycles. This work presents the highly competitive performance of Li-S batteries on the areal capacity and capacity decay.

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