| 1. |
- Dong, Qibing, et al.
(författare)
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Regulating concentration of surface oxygen vacancies in Bi 2 MoO 6 /Bi-MOF for boosting photocatalytic ammonia synthesis
- 2024
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Ingår i: Journal of Catalysis. - 0021-9517 .- 1090-2694. ; 433
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Tidskriftsartikel (refereegranskat)abstract
- Surface oxygen vacancies (OVs) engineering has been widely adopted as an effective strategy to enhance photocatalytic performance. At present, photocatalytic systems capable of precisely regulating surface OVs concentrations, which could help illuminate the effects of the surface OVs concentration on N2 fixation activity, are still scarce. Herein, bismuth-based metal organic framework (Bi-MOF) was loaded onto the surface of Bi2MoO6 (BMO) as an operable platform, and the OVs concentration in the Bi-MOF component of BMO/Bi-MOF could be regulated by reduction of bismuth ions therein. Experimental results confirm that optimum construction of OVs in the Bi-MOF promotes the photoelectrons transfer from BMO to Bi-MOF, facilitating the activation of N2 at OVs. Consequently, the optimized catalyst shows superior performance in NH3 production, which reaches 125.78 μmol h−1 g−1, 21.4 higher than that of BMO. This work underline the significance of regulating surface OVs concentration, providing inspiration for the development of efficient OVs-modified photocatalysts.
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| 2. |
- He, Jiansen, et al.
(författare)
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Direct Measurement of the Dissipation Rate Spectrum around Ion Kinetic Scales in Space Plasma Turbulence
- 2019
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Ingår i: Astrophysical Journal. - : IOP PUBLISHING LTD. - 0004-637X .- 1538-4357. ; 880:2
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Tidskriftsartikel (refereegranskat)abstract
- The energy of turbulence in the universe, which cascades from large fluid scales to small kinetic scales, is believed to be dissipated through conversion to thermal or nonthermal kinetic energy. However, identifying the dissipation processes and measuring the dissipation rate in turbulence remain challenging. Based on unprecedented high-quality measurements of space plasma turbulence by the Magnetospheric Multiscale mission, we propose a novel approach to measure the scale-dependent spectrum of the energy conversion rate between the fluctuating electromagnetic energy and plasma kinetic energy. The energy conversion rate spectrum is found to show a positive bulge around the ion kinetic scale, which clearly indicates the dissipation of the turbulent energy. The energy dissipation rate around the ion scale is estimated to be 0.5 x 10(6) J kg(-1) s(-1). This work provides basic information on local dissipation in magnetosheath turbulence and sets up a new paradigm for studying the dissipation of universal plasma turbulence.
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| 3. |
- Jiang, Zeyu, et al.
(författare)
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Enhanced Interface Charge Transfer of Z-Scheme Photocatalyst by Br Substitution at the Bay Position in Perylene Tetracarboxylic Diimide
- 2020
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Ingår i: Solar RRL. - : WILEY-V C H VERLAG GMBH. - 2367-198X. ; 4:10
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Tidskriftsartikel (refereegranskat)abstract
- Z-scheme heterojunction photocatalysts (ZsHP) have attracted significant attention due to their excellent carrier recombination suppression and charge potential enhancement properties. However, the photocatalytic performance of ZsHP is limited by inefficient charge transfer at the heterojunction interface, mainly due to electron trapping by O-2 or H+ in part B and the large energy gap between its conduction band (CB) and the valence band (VB) of part A. Herein, perylene tetracarboxylic diimide (PTCDI, part B) and g-C3N4 (part A) are used to fabricate an organic ZsHP (PI-g-C3N4) as a novel strategy to significantly improve interfacial charge transfer efficiency by tailoring the Br substitution at the PTCDI bay position. Br substitution at the bay position reduce electron trapping in part B and bring the CB of part B closer to the VB of part A. Moreover, Br substitution enhance the electric field from g-C3N4 to PTCDI, enhancing the interfacial charge transfer of the ZsHP. These findings enable the design of ZsHP with tunable interface electron-transfer efficiencies.
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| 4. |
- Hu, Guangzhi, et al.
(författare)
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Atomistic understanding of the origin of high oxygen reduction electrocatalytic activity of cuboctahedral Pt3Co-Pt core-shell nanoparticles
- 2016
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Ingår i: Catalysis Science & Technology. - : Royal Society of Chemistry (RSC). - 2044-4753 .- 2044-4761. ; 6:5, s. 1393-1401
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Tidskriftsartikel (refereegranskat)abstract
- PtM-based core-shell nanoparticles are a new class of active and stable nanocatalysts for promoting oxygen reduction reaction (ORR); however, the understanding of their high electrocatalytic performance for ORR at the atomistic level is still a great challenge. Herein, we report the synthesis of highly ordered and homogeneous truncated cuboctahedral Pt3Co-Pt core-shell nanoparticles (cs-Pt3Co). By combining atomic resolution electron microscopy, X-ray photoelectron spectroscopy, extensive first-principles calculations, and many other characterization techniques, we conclude that the cs-Pt3Co nanoparticles are composed of a complete or nearly complete Pt monolayer skin, followed by a secondary shell containing 5-6 layers with similar to 78 at% of Pt, in a Pt3Co configuration, and finally a Co-rich core with 64 at% of Pt. Only this particular structure is consistent with the very high electrocatalytic activity of cs-Pt3Co nanoparticles for ORR, which is about 6 times higher than commercial 30%-Pt/Vulcan and 5 times more active than non-faceted (spherical) alloy Pt3Co nanoparticles. Our study gives an important insight into the atomistic design and understanding of advanced bimetallic nanoparticles for ORR catalysis and other important industrial catalytic applications.
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| 5. |
- Ren, Haitao, et al.
(författare)
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Facile synthesis of nitrogen, sulfur co-doped carbon quantum dots for selective detection of mercury (II)
- 2024
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Ingår i: Environmental Chemistry Letters. - 1610-3653 .- 1610-3661. ; 22:1, s. 35-41
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Tidskriftsartikel (refereegranskat)abstract
- Developing carbon quantum dots with high throughput and quantum yields is important to boost their application in environmental detection. This study proposes nitrogen, sulfur co-doped carbon quantum dots as a fluorescent probe for mercury detection in an aqueous environment, which was synthesized by a facile and high-output tactic using methyl orange as a precursor for the first time. Results demonstrate that the obtained carbon quantum dots have a high selectivity, low detection limit of 237 nM, and fast response time, approximately 30 s, for trace mercury. The detection mechanism involves the synergistic action of static quenching, inner filter effect, and photo-induced electron transfer. Moreover, results show a high product yield (75.6%) and quantum yield (29.4%), which are higher compared to previous studies. These findings indicate that developed carbon quantum dots are promising sensing nanomaterials for mercury detection.
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| 6. |
- Zhou, Meng, et al.
(författare)
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Photocatalytic removal of NO by intercalated carbon nitride: The effect of group IIA element ions
- 2020
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Ingår i: Applied Catalysis B. - : ELSEVIER. - 0926-3373 .- 1873-3883. ; 273
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Tidskriftsartikel (refereegranskat)abstract
- In this study, Group IIA element ion-doped g-C3N4 samples were synthesized to eliminate above two disadvantages and increase photocatalytic NO removal activity. The experimental results showed that the Group IIA element ions could form coordination bonds with the nitrogen atoms in the triazine rings of g-C3N4 that distorted the g-C3N4 structure because of uneven force. The structure distortion destroyed the surface electronic delocalization and suppressed the recombination of surface charge carriers. Additionally, the formed coordinate bonds connected two adjacent layers and served as interlayer electron channels, which could significantly improve the electron transport between two layers. Additionally, structural distortions created more amino and imino groups, which are the chemisorption sites of O-2. Therefore, the modified g-C3N4 samples produced more reactive oxygen species to remove NO. The degree of distortion and the NO removal activity increased as the Group IIA atomic number increased.
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