| 1. |
- Fan, Lizhou, et al.
(författare)
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Molecular Functionalization of NiO Nanocatalyst for Enhanced Water Oxidation by Electronic Structure Engineering
- 2020
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 13:22, s. 5901-5909
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Tidskriftsartikel (refereegranskat)abstract
- Tuning the local environment of nanomaterial-based catalysts has emerged as an effective approach to optimize their oxygen evolution reaction (OER) performance, yet the controlled electronic modulation around surface active sites remains a great challenge. Herein, directed electronic modulation of NiO nanoparticles was achieved by simple surface molecular modification with small organic molecules. By adjusting the electronic properties of modifying molecules, the local electronic structure was rationally tailored and a close electronic structure-activity relationship was discovered: the increasing electron-withdrawing modification readily decreased the electron density around surface Ni sites, accelerating the reaction kinetics and improving OER activity, and vice versa. Detailed investigation by operando Raman spectroelectrochemistry revealed that the electron-withdrawing modification facilitates the charge-transfer kinetics, stimulates the catalyst reconstruction, and promotes abundant high-valent gamma-NiOOH reactive species generation. The NiO-C(6)F(5)catalyst, with the optimized electronic environment, exhibited superior performance towards water oxidation. This work provides a well-designed and effective approach for heterogeneous catalyst fabrication under the molecular level.
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| 2. |
- Guo, Yaxiao, et al.
(författare)
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Molybdenum and boron synergistically boosting efficient electrochemical nitrogen fixation
- 2020
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Ingår i: Nano Energy. - : Elsevier Ltd. - 2211-2855 .- 2211-3282. ; 78
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Tidskriftsartikel (refereegranskat)abstract
- Ammonia production consumes ~2% of the annual worldwide energy supply, therefore strategic alternatives for the energy-intensive ammonia synthesis through the Haber-Bosch process are of great importance to reduce our carbon footprint. Inspired by MoFe-nitrogenase and the energy-efficient and industrially feasible electrocatalytic synthesis of ammonia, we herein establish a catalytic electrode for artificial nitrogen fixation, featuring a carbon fiber cloth fully grafted by boron-doped molybdenum disulfide (B-MoS2/CFC) nanosheets. An excellent ammonia production rate of 44.09 μg h–1 cm–2 is obtained at −0.2 V versus the reversible hydrogen electrode (RHE), whilst maintaining one of the best reported Faradaic efficiency (FE) of 21.72% in acidic aqueous electrolyte (0.1 M HCl). Further applying a more negative potential of −0.25 V renders the best ammonia production rate of 50.51 μg h–1 cm–2. A strong-weak electron polarization (SWEP) pair from the different electron accepting and back-donating capacities of boron and molybdenum (2p shell for boron and 5d shell for molybdenum) is proposed to facilitate greatly the adsorption of non-polar dinitrogen gas via N≡N bond polarization and the first protonation with large driving force. In addition, for the first time a visible light driven photo-electrochemical (PEC) cell for overall production of ammonia, hydrogen and oxygen from water + nitrogen, is demonstrated by coupling a bismuth vanadate BiVO4 photo-anode with the B-MoS2/CFC catalytic cathode.
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| 3. |
- Cai, Xiao, et al.
(författare)
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Turbulent burning velocity and its related statistics of ammoniahydrogenair jet flames at high Karlovitz number : Effect of differential diffusion
- 2023
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Ingår i: Proceedings of the Combustion Institute. - : Elsevier BV. - 1540-7489. ; 39:4, s. 4215-4226
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Tidskriftsartikel (refereegranskat)abstract
- To clarify the role of differential diffusion in highly turbulent premixed flames, a series of turbulent premixed ammonia/hydrogen/air flames were investigated using the NH-PLIF diagnostics. The investigated flames have almost the same laminar burning velocity, SL, but are characterized by different Lewis number, Le, from 0.56 to 1.77. The Karlovitz number, Ka, of these flames ranges from 11 to 1052, and the turbulence intensity, u'/SL, covers from 10 to 156. It is observed that the global consumption speed, ST,GC/SL, of sub-unity Le flames is much larger than that of super-unity Le flames at high Ka, indicating that the differential diffusion plays a significant role in highly turbulent flames. The flame surface density and the area ratio of turbulent flames with different Le are, however, similar under wide turbulent conditions. The stretch factor of sub-unity Le flames is estimated to be significantly larger than that of super-unity Le cases. The enhanced ST,GC of sub-unity Le flames is suggested to be attributed to the promotion of local burning rates by the couple effect of differential diffusion and turbulent flame stretch within the flame brush, rather than the enlargement of flame surface area at high Ka. Furthermore, three correlations for the ST,GC were developed based on Damkohler's second hypothesis with consideration of the Le effect. The correlation of ST,GC/SL - (ReTLe-2)0.5 is further validated by using small-scale methane/air and large-scale ammonia/air flames at high Ka, where ReT is turbulent Reynolds number. It suggests that the ST,GC is roughly inversely proportional to the Le, and the differential diffusion effect should be included in the theoretical analysis and numerical simulation of highly turbulent flames.
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| 4. |
- Dan, Meng, et al.
(författare)
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Beyond hydrogen production : Solar−driven H2S−donating value−added chemical production over MnxCd1−xS/CdyMn1−yS catalyst
- 2021
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Ingår i: Applied Catalysis B: Environmental. - : Elsevier BV. - 0926-3373. ; 284
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Tidskriftsartikel (refereegranskat)abstract
- Simultaneous hydrogen (H2) evolution and value−added chemicals production are highly attractive but have not drawn enough attention. Here, we demonstrate a hydrogen sulphide (H2S)−induced product−targeting (HIPT) strategy for the coproduction of H2 and valuable chemical feedstocks from Na2S/Na2SO3 via overall H2S splitting using a MnxCd1−xS/CdyMn1−yS catalyst driven by visible light excitation. With this chemistry, 113 mmol g−1 h−1 of hydrogen evolution rate is achieved, surpassing most of the previously reported state-of-the-art photocatalyst, together with the production of value−added Na2S2O3 with nearly 100% selectivity. This work not only provides a good example for solar energy conversion via overall H2S splitting, but also offers new insights into the resource utilization of sacrificial donor (Na2S/Na2SO3) in various catalytic fields such as H2O splitting and CO2 reduction.
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| 5. |
- Fan, Hongchao, et al.
(författare)
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Shell model representation as a substitute of LOD3 for 3D modeling in CityGML
- 2011
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Ingår i: Geo-spatial Information Science. - : Informa UK Limited. - 1009-5020 .- 1993-5153. ; 14:2, s. 78-84
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Tidskriftsartikel (refereegranskat)abstract
- The OGC standard for 3D city modeling is widely used in an increasing number of applications. It defines five consecutive Levels of Detail (LoD0 to LoD4 with increasing accuracy and structural complexity), in which LoD3 includes all exterior appearances and geometrical details and subsequently requires much storage space. A new LoD is introduced as shell model with the exterior shell of the LoD3 model and the opening objects like windows, doors as well as smaller façade objects are projected onto walls. In this paper, a user survey is presented. The results of this survey show that the shell model can give users almost the same visual impression as the LoD3 model. Furthermroe, algorithms are developed to extract the shell model from LoD3 model. Experiments show that this shell model can reduce up to 90% storage of the original LoD3 model. Therefore, on one hand it can be used as a substitute for a LoD3 model for the visualization on small displays. On the other hand, it can be treated as a sub-level of detail (SLoD3) in CityGML, since it retains almost the same amount of information but requires much less storage space.
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| 6. |
- Yang, Fuliu, et al.
(författare)
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Efficient SO2 capture at ultra-low concentration using a hybrid absorbent of deep eutectic solvent and ethylene glycol
- 2023
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Ingår i: Journal of Molecular Liquids. - : Elsevier. - 0167-7322 .- 1873-3166. ; 382
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Tidskriftsartikel (refereegranskat)abstract
- Deep eutectic solvents (DESs) are considered as the highly effective absorbents for sulfur dioxide (SO2) capture. However, the high viscosity of DESs and the resulting slow absorption rate as well as low absorption capacity at low SO2 concentration seriously hinder their industrial application. In this study, DES of N-methyldiethanolamine (MDEA) and imidazole (Im) is simply blended with ethylene glycol (EG) forming a hybrid absorbent, namely MDEA/Im-EG, which exhibits extremely high SO2 capture capacity at low concentration. In particular, SO2 capture capacity in MDEA/Im-EG (molar ratio = 1:1) reaches 0.446 g SO2/g absorbent at 293.2 K with SO2 concentration of 2000 ppm. Moreover, the corresponding desorption enthalpy is only −40.67 kJ/mol. To well understand the results, thermodynamic analysis of SO2 capture is performed and the SO2 capture mechanism is speculated by nuclear magnetic resonance and Fourier transform infrared spectroscopy.
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| 7. |
- Zhang, Biaobiao, et al.
(författare)
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Advancing Proton Exchange Membrane Electrolyzers with Molecular Catalysts
- 2020
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Ingår i: Joule. - : Elsevier BV. - 2542-4351. ; 4:7, s. 1408-1444
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Forskningsöversikt (refereegranskat)abstract
- Molecular catalysts possess numerous advantages over conventional heterogeneous catalysts in precise structure regulation, in-depth mechanism understanding, and efficient metal utilization. Various molecular catalysts have been reported that efficiently catalyze reactions involved in artificial photosynthesis, however, these catalysts have been rarely considered in view of practical applications. With this review, firstly we demonstrate in the introduction that molecular catalysts can bring new opportunities to proton exchange membrane (PEM) electrolyzers. In the following parts, we provide an overview of molecular catalyst modified carbon materials developed for electrochemical water oxidation, proton reduction, and CO2 reduction reactions. These materials and the involved immobilization strategies as well as characterization techniques may be directly employed in the investigations of application of molecular catalysts in PEM electrolyzers. The future scientific perspectives and challenges to advance this promising, yet underdeveloped technology for solar fuel production, integrating PEM electrolyzer with molecular-level catalysis, are discussed in the conclusions.
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