| 1. |
- Chen, Zhiwen, et al.
(författare)
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Interface engineering of NiS@MoS2 core-shell microspheres as an efficient catalyst for hydrogen evolution reaction in both acidic and alkaline medium
- 2021
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Ingår i: Journal of Alloys and Compounds. - : ELSEVIER SCIENCE SA. - 0925-8388 .- 1873-4669. ; 853
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Tidskriftsartikel (refereegranskat)abstract
- Electrochemical splitting of water is one of the most reliable and effective ways for the sustainable production of pure hydrogen on a large scale, while the core of this technology lies in the development of highly active non-noble-metal-based electrocatalysts to lower the large dynamic overpotentials of electrode materials. Here, an interface engineering strategy is demonstrated to construct an efficient and stable catalyst based on NiS@MoS2 core-shell hierarchical microspheres for the hydrogen evolution reactions (HER). The ultrathin MoS2 nanosheets in-situ grow on the surface of NiS hierarchical micro-sized spheres constructed by porous nanoplates, endowing the composites with rich interfaces, well-exposed electroactive edges, high structural porosity and fast transport channels. These advantages are favorable for the improvement of catalytic sites and the transport of catalysis-relevant species. More importantly, the intimate contact between MoS2 nanosheets and NiS nanoplates synergistically favors the chemical sorption of hydrogen intermediates, thereby reducing the reaction barrier and accelerating the HER catalytic process. As a result, the optimized NiS@MoS2 catalyst manifests impressive HER activity and durability, with a low overpotential of 208 mV in 0.5 M H2SO4 and 146 mV in 1.0 M KOH at 10 mA cm(-2), respectively. This work not only provides an effective way to construct core-shell hierarchical microspheres but also a multiscale strategy to regulate the electronic structure of heterostructured materials for energy-related applications. (C) 2020 Elsevier B.V. All rights reserved.
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| 2. |
- Huang, Shoushuang, et al.
(författare)
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An advanced electrocatalyst for efficient synthesis of ammonia based on chemically coupled NiS@MoS2 heterostructured nanospheres
- 2021
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Ingår i: Sustainable Energy & Fuels. - : Royal Society of Chemistry. - 2398-4902. ; 5:10, s. 2640-2648
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Tidskriftsartikel (refereegranskat)abstract
- The electrochemical reduction of nitrogen, as a sustainable alternative to the known Haber-Bosch process, possesses promising application prospects in the development of renewable energy storage systems. However, the yield of NH3 and Faraday efficiency are usually very low owing to the loss of active electrocatalysts and competitive hydrogen evolution reactions. Herein, uniform NiS@MoS2 core-shell microspheres are controllably prepared as a potential catalyst for an ambient electrocatalytic N-2 reduction reaction. The NiS@MoS2 microspheres possess highly active intrinsic, sufficient accessible active sites, high structural porosity, and convenient transport channels, consequently boosting the transmission of electrons and mass. Additionally, the interfacial interaction between NiS and MoS2 facilitates electron transfer, which further improves the catalytic activity by optimizing the free energies of reaction intermediates. As a result, the titled NiS@MoS2 shows excellent electrochemical activity and selectivity, capable of achieving a relatively high NH3 yield of 9.66 mu g h(-1) mg(cat)(-1) at -0.3 V (vs. the reversible hydrogen electrode, RHE) and a high FE of 14.8% at -0.1 V vs. RHE in 0.1 M Na2SO4. The work demonstrated here may open a new avenue for the rational design and synthesis of catalysts for the electrochemical synthesis of ammonia.
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| 3. |
- Le, Thanh-Tung, et al.
(författare)
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Carbon-Decorated Fe3S4-Fe7Se8 Hetero-Nanowires: Interfacial Engineering for Bifunctional Electrocatalysis Toward Hydrogen and Oxygen Evolution Reactions
- 2020
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Ingår i: Journal of the Electrochemical Society. - : ELECTROCHEMICAL SOC INC. - 0013-4651 .- 1945-7111. ; 167:8
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Tidskriftsartikel (refereegranskat)abstract
- The design and synthesis of complex multi-component heterostructures is an effective strategy to fabricate cost-efficient catalysts for electrochemical water splitting. Herein, one-dimensional porous Fe3S4-Fe7Se8 heterostructured nanowires confined in carbon (Fe3S4-Fe7Se8@C) were synthesized via the selenization of Fe-based organic-inorganic nanowires. Benefiting from the merits of morphology, composition and surface structure characteristics, i.e., the high structural void porosity, the direct electrical pathways of nanowire topology and the conductive carbon layer coating, the titled catalyst not only offered a larger accessible electrocatalytic interface but also facilitated diffusion of the electrolyte and gas. Moreover, the electron redistribution at the Fe3S4-Fe7Se8 heterojunction interfaces reduced the adsorption free-energy barriers on the active sites, endowing the catalysts with faster reaction kinetics and improved electrocatalytic activity. Accordingly, the optimal Fe3S4-Fe7Se8@C produced a low hydrogen evolution reaction overpotential of 124 mV at 10 mA cm (-2) with a Tafel slope of 111.2 mV dec(-1), and an ultralow oxygen evolution reactions overpotential of 219 mV at 20 mA cm (-2 ), respectively. When applied as both anode and cathode for overall water splitting, a low battery voltage of 1.67 V was achieved along with excellent stability for at least 12 h. The work presented here offered a feasible scheme to fabricate non-noble metal-based electrocatalysts for water splitting. (C) 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.
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| 4. |
- Liu, Huizeng, et al.
(författare)
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Estimating ultraviolet reflectance from visible bands in ocean colour remote sensing
- 2021
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Ingår i: Remote Sensing of Environment. - : Elsevier BV. - 0034-4257 .- 1879-0704. ; 258
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, ultraviolet (UV) bands have received increasing attention from the ocean colour remote sensing community, as they may contribute to improving atmospheric correction and inherent optical properties (IOPs) retrieval. However, most ocean colour satellite sensors do not have UV bands, and the accurate retrieval of UV remote sensing reflectance (Rrs) from UV satellite data is still a challenge. In order to address this problem, this study proposes a hybrid approach for estimating UV Rrs from the visible bands. The approach was implemented with two popular ocean colour satellite sensors, i.e. GCOM-C SGLI and Sentinel-3 OLCI. In situ Rrs collected globally and simulated Rrs spectra were used to develop UV Rrs retrieval models, and UV Rrs values at 360, 380 and 400 nm were estimated from visible Rrs spectra. The performances of the established models were evaluated using in situ Rrs and satellite data, and applied to a semi-analytical algorithm for IOPs retrieval. The results showed that: (i) UV Rrs retrieval models had low uncertainties with mean absolute percentage differences (MAPD) less than 5%; (ii) the model assessment with in situ Rrs showed high accuracy (r = 0.92–1.00 and MAPD = 1.11%–10.95%) in both clear open ocean and optically complex waters; (iii) the model assessment with satellite data indicated that model-estimated UV Rrs were more consistent with in situ values than satellite-derived UV Rrs; and (iv) model-estimated UV Rrs may improve the decomposition accuracy of absorption coefficients in semi-analytical IOPs algorithm. Thus, the proposed method has great potentials for reconstructing UV Rrs data and improving IOPs retrieval for historical satellite sensors, and might also be useful for UV-based atmospheric correction algorithms.
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| 5. |
- Liu, Huizeng, et al.
(författare)
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Evaluation of Ocean Color Atmospheric Correction Methods for Sentinel-3 OLCI Using Global Automatic In Situ Observations
- 2022
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Ingår i: IEEE Transactions on Geoscience and Remote Sensing. - 0196-2892 .- 1558-0644. ; 60
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Tidskriftsartikel (refereegranskat)abstract
- The Ocean and Land Color Instrument (OLCI) on Sentinel-3 is one of the most advanced ocean color satellite sensors for aquatic environment monitoring. However, limited studies have been focused on a comprehensive assessment of atmospheric correction (AC) methods for OLCI. In an attempt to fill the gap, this study evaluated seven different AC methods for OLCI using global automatic in situ observations from Aerosol Robotic Network-Ocean Color (AERONET-OC). Results showed that the POLYnomial-based algorithm applied to MERIS (POLYMER) had the best performance for bands with wavelength ≤ 443 nm, and the SeaDAS method based on 779 and 865 nm was the best for longer spectral bands; however, SeaDAS (SeaWiFS Data Analysis System) processing algorithm based on 779 and 1020 nm, as well as 865 and 1020 nm, obtained degraded AC performance; Case 2 Regional CoastColor (C2RCC) also produced large uncertainties; Baseline AC (BAC) method might be better than SeaDAS method; and simple subtraction method was the worst except for turbid waters. POLYMER and C2RCC underestimated high remote sensing reflectance (Rrs) at red and green bands; SeaDAS method based on 779 and 865 nm held an advantage for clear waters over the other two band combinations, while their difference turned small for turbid waters. AC uncertainties generally impacted the performance of chlorophyll retrievals. POLYMER outperformed other methods for chlorophyll retrieval. This study provides a good reference for selecting a suitable AC method for aquatic environment monitoring with Sentinel-3 OLCI.
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| 6. |
- Wang, Shangdai, et al.
(författare)
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Multi-functional NiS2/FeS2/N-doped carbon nanorods derived from metal-organic frameworks with fast reaction kinetics for high performance overall water splitting and lithium-ion batteries
- 2019
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Ingår i: Journal of Power Sources. - : ELSEVIER. - 0378-7753 .- 1873-2755. ; 436
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Tidskriftsartikel (refereegranskat)abstract
- The development of cost-effective, highly efficient and robust multi-functional electrode materials can dramatically reduce the overall cost of electrochemical devices. We here report the controlled synthesis of NiS2/FeS2 nanoparticles encapsulated in N-doped carbon nanorods (NiS2/FeS2/NC) through carbonization and sulfurization of Fe/Ni-based bimetallic metal-organic frameworks. Benefiting from both structural and compositional characteristics, the resulting NiS2/FeS2/NC nanorods possess abundant active sites, high electrical conductivity and rapid mass transfer, thereby delivering 10 and 20 mA cm(-2) at overpotential of 172 mV and 231 mV towards the hydrogen evolution reaction and oxygen evolution reaction with robust stability in 1.0 M KOH solution, respectively. When employed as a bifunctional electrocatalyst for overall water splitting, it requires only 1.58 V to deliver a current density of 10 mA cm(-2) in 1.0 M KOH, outperforming that of the commercial Pt/C parallel to RuO2. Additionally, lithium-ion batteries tests also show high reversible capacity (718 mA h g(-1) at 100 mA g(-1)) and excellent cycling stability and rate performance. The work in this paper not only provides a promising strategy for designing efficient multi-functional electrode materials with similar morphology and structure, but also can be extended to the synthesis of other mixed metal sulfides for energy conversion and storage.
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