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| 2. |
- Cha, Gihoon, et al.
(författare)
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As a single atom Pd outperforms Pt as the most active co-catalyst for photocatalytic H-2 evolution
- 2021
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Ingår i: ISCIENCE. - : Elsevier BV. - 2589-0042. ; 24:8
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Tidskriftsartikel (refereegranskat)abstract
- Here, we evaluate three different noble metal co-catalysts (Pd, Pt, and Au) that are present as single atoms (SAs) on the classic benchmark photocatalyst, TiO2. To trap the single atoms on the surface, we introduced controlled surface vacancies (Ti3+-Ov) on anatase TiO2 nanosheets by a thermal reduction treatment. After anchoring identical loadings of single atoms of Pd, Pt, and Au, we measure the photocatalytic H-2 generation rate and compare it to the classic nanoparticle co-catalysts on the nanosheets. While nanoparticles yield the well-established the hydrogen evolution reaction activity sequence (Pt > Pd > Au), for the single atom form, Pd radically outperforms Pt and Au. Based on density functional theory (DFT), we ascribe this unusual photocatalytic co-catalyst sequence to the nature of the charge localization on the noble metal SAs embedded in the TiO2 surface.
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| 3. |
- Hubicka, Z., et al.
(författare)
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Deposition of hematite Fe2O3 thin film by DC pulsed magnetron and DC pulsed hollow cathode sputtering system
- 2013
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Ingår i: Thin Solid Films. - : Elsevier BV. - 0040-6090 .- 1879-2731. ; 549, s. 184-191
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Tidskriftsartikel (refereegranskat)abstract
- Semiconducting hematite Fe2O3 thin films were fabricated by means of reactive sputtering in a high power DC pulsed magnetron (HIPIMS) and in a DC pulsed hollow cathode plasma jet sputtering system. Fused silica slides (quartz) were used as substrates. Both plasma processes were monitored with the help of a quartz crystal monitor (QCM) that was also fitted with magnetic field electron suppression filter and biased collecting electrode. This set up measured the deposition rate and the ratio of ionized to neutral fluxes of depositing particles on the substrate during the coating process. The deposition methods were compared in terms of the properties of produced films such as crystalline structure, optical absorption and surface topography. The as-deposited hematite Fe2O3 thin films (without annealing) and after their thermal treatment (with annealing) were examined.
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| 4. |
- Jayaramulu, K., et al.
(författare)
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Covalent Graphene-MOF Hybrids for High-Performance Asymmetric Supercapacitors
- 2021
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Ingår i: Advanced Materials. - : Wiley-VCH Verlag. - 0935-9648 .- 1521-4095. ; 33:4
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the covalent attachment of an amine functionalized metal-organic framework (UiO-66-NH2 = Zr6O4(OH)4(bdc-NH2)6; bdc-NH2 = 2-amino-1,4-benzenedicarboxylate) (UiO-Universitetet i Oslo) to the basal-plane of carboxylate functionalized graphene (graphene acid = GA) via amide bonds is reported. The resultant GA@UiO-66-NH2 hybrid displayed a large specific surface area, hierarchical pores and an interconnected conductive network. The electrochemical characterizations demonstrated that the hybrid GA@UiO-66-NH2 acts as an effective charge storing material with a capacitance of up to 651 F g−1, significantly higher than traditional graphene-based materials. The results suggest that the amide linkage plays a key role in the formation of a π-conjugated structure, which facilitates charge transfer and consequently offers good capacitance and cycling stability. Furthermore, to realize the practical feasibility, an asymmetric supercapacitor using a GA@UiO-66-NH2 positive electrode with Ti3C2TX MXene as the opposing electrode has been constructed. The cell is able to deliver a power density of up to 16 kW kg−1 and an energy density of up to 73 Wh kg−1, which are comparable to several commercial devices such as Pb-acid and Ni/MH batteries. Under an intermediate level of loading, the device retained 88% of its initial capacitance after 10 000 cycles. © 2020 The Authors. Advanced Materials published by Wiley-VCH GmbH
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