| 1. |
- Li, Gang, et al.
(författare)
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Selective Electrochemical Alkaline Seawater Oxidation Catalyzed by Cobalt Carbonate Hydroxide Nanorod Arrays with Sequential Proton-Electron Transfer Properties
- 2021
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 9:2, s. 905-913
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Tidskriftsartikel (refereegranskat)abstract
- Seawater oxygen evolution is one of the promising energy conversion technologies for large-scale renewable energy storage. It requires efficient catalysts to accelerate the oxygen evolution reaction (OER) for sustained water oxidation, avoiding chlorine evolution under acidic conditions or hypochlorite formation in alkaline solutions. Conventional metal oxide-based OER catalysts follow the adsorbate evolution mechanism that involves concerted proton-electron transfer steps at the active sites. Thus, on the scale of reversible hydrogen electrode, their catalytic activity is independent of the pH of electrolytes. In the present study, nanostructured cobalt carbonate hydroxide (CoCH) with sequential proton-electron transfer properties was tested as a catalyst for seawater oxygen evolution. CoCH exhibited pH-dependent water oxidation activities, thereby providing larger potential and current operating windows for selective water oxidation compared to the catalysts with pH-independent OER activities. The operating window can be further expanded by increasing the pH of the electrolyte.
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| 2. |
- Liu, Chang, et al.
(författare)
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A dendritic Sb2Se3/In2S3 heterojunction nanorod array photocathode decorated with a MoSx catalyst for efficient solar hydrogen evolution
- 2020
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Ingår i: Journal of Materials Chemistry A. - : Royal Society of Chemistry (RSC). - 2050-7488 .- 2050-7496. ; 8:44, s. 23385-23394
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Tidskriftsartikel (refereegranskat)abstract
- Developing cost-effective photocathodes that show desirable performance for use in commercial photoelectrochemical water splitting devices remains a fundamental and practical challenge. Sb2Se3 semiconductors satisfy most of the demands expected for an ideal highly efficient photocathode, including favorable cost and optoelectronic properties. Herein, we have demonstrated outstanding photoelectrodes using a noble-metal-free catalyst, namely, a MoSx-decorated low-cost Sb2Se3/In2S3 heterojunction, as the photocathode. This enabled a maximum photocurrent density of up to -27 mA cm(-2) (0 V vs. RHE, 100 mW cm(-2), AM 1.5G filter) with a remarkable half solar-to-hydrogen conversion efficiency (STH) of 2.6%, obtained via decreasing charge recombination and accelerating charge transfer through morphological optimization of the In2S3 layer.
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| 3. |
- Zhao, Yilong, et al.
(författare)
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Efficient urea electrosynthesis from carbon dioxide and nitrate via alternating Cu–W bimetallic C–N coupling sites
- 2023
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 14:1
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Tidskriftsartikel (refereegranskat)abstract
- Electrocatalytic urea synthesis is an emerging alternative technology to the traditional energy-intensive industrial urea synthesis protocol. Novel strategies are urgently needed to promote the electrocatalytic C–N coupling process and inhibit the side reactions. Here, we report a CuWO4 catalyst with native bimetallic sites that achieves a high urea production rate (98.5 ± 3.2 μg h−1 mg−1cat) for the co-reduction of CO2 and NO3− with a high Faradaic efficiency (70.1 ± 2.4%) at −0.2 V versus the reversible hydrogen electrode. Mechanistic studies demonstrated that the combination of stable intermediates of *NO2 and *CO increases the probability of C–N coupling and reduces the potential barrier, resulting in high Faradaic efficiency and low overpotential. This study provides a new perspective on achieving efficient urea electrosynthesis by stabilizing the key reaction intermediates, which may guide the design of other electrochemical systems for high-value C–N bond-containing chemicals.
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| 4. |
- Li, Yingzheng, et al.
(författare)
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Switching the O-O Bond Formation Pathways of Ru-pda Water Oxidation Catalyst by Third Coordination Sphere Engineering
- 2021
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Ingår i: RESEARCH. - : American Association for the Advancement of Science (AAAS). - 2639-5274. ; 2021
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Tidskriftsartikel (refereegranskat)abstract
- Water oxidation is a vital anodic reaction for renewable fuel generation via electrochemical- and photoelectrochemical-driven water splitting or CO2 reduction. Ruthenium complexes, such as Ru-bda family, have been shown as highly efficient water-oxidation catalysts (WOCs), particularly when they undergo a bimolecular O-O bond formation pathway. In this study, a novel Ru(pda)-type (pda(2-) = 1,10-phenanthroline-2,9-dicarboxylate) molecular WOC with 4-vinylpyridine axial ligands was immobilized on the glassy carbon electrode surface by electrochemical polymerization. Electrochemical kinetic studies revealed that this homocoupling polymer catalyzes water oxidation through a bimolecular radical coupling pathway, where interaction between two Ru(pda)-oxyl moieties (I2M) forms the O-O bond. The calculated barrier of the I2M pathway by density-functional theory (DFT) is significantly lower than the barrier of a water nucleophilic attack (WNA) pathway. By using this polymerization strategy, the Ru centers are brought closer in the distance, and the O-O bond formation pathway by the Ru (pda) catalyst is switched from WNA in a homogeneous molecular catalytic system to I2M in the polymerized film, providing some deep insights into the importance of third coordination sphere engineering of the water oxidation catalyst.
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| 5. |
- Li, Fusheng, 1985-, et al.
(författare)
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Electroless Plating of NiFeP Alloy on the Surface of Silicon Photoanode for Efficient Photoelectrochemical Water Oxidation
- 2020
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 12:10, s. 11479-11488
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Tidskriftsartikel (refereegranskat)abstract
- N- type silicon is a kind of semiconductor with a narrow band gap that has been reported as an outstanding light-harvesting material for photoelectrochemical (PEC) reactions. Decorating a thin catalyst layer on the n-type silicon surface can provide a direct and effective route toward PEC water oxidation. However, most of catalyst immobilization methods for reported n-type silicon photoanodes have been based on energetically demanding, time-consuming, and high-cost processes. Herein, a high-performance NiFeP alloy (NiFeP)-decorated n-type micro-pyramid silicon array (n-Si) photoanode (NiFeP/n-Si) was prepared by a fast and low-cost electroless deposition method for light-driven water oxidation reaction. The saturated photocurrent density of NiFeP/n-Si can reach up to similar to 40 mA cm(-2) and a photocurrent density of 15.5 mA cm(-2) can be achieved at 1.23 V-RHE under light illumination (100 mW cm(-2), AM1.5 filter), which is one of the most promising silicon-based photoanodes to date. The kinetic studies showed that the NiFeP on the silicon photoanodes could significantly decrease the interfacial charge recombination between the n-type silicon surface and electrolyte.
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| 6. |
- Ma, Shengyu, et al.
(författare)
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Metal–Molybdenum Sulfide Nanosheet Arrays Prepared by Anion Exchange as Catalysts for Hydrogen Evolution
- 2020
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Ingår i: Energy Technology. - : Wiley-VCH Verlag. - 2194-4288 .- 2194-4296. ; 8:10
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Tidskriftsartikel (refereegranskat)abstract
- Metal–molybdenum sulfide (MMoSx)-based catalysts exhibit good performance over a wide pH range toward hydrogen evolution with relatively low overvoltage requirements. Therefore, they are considered as suitable alternatives to Pt as catalysts for hydrogen evolution reaction. Herein, self-supported amorphous CuMoSx and NiMoSx nanosheet arrays are prepared on copper foam (CF) and nickel foam (NF), respectively, through an anion-exchange strategy. CF and NF are first converted into CuTCNQ and NiTCNQ nanowire arrays (TCNQ = tetracyanoquinodimethane), which are then in situ reacted with (NH4)2MoS4 solution to generate amorphous CuMoSx/CF and NiMoSx/NF nanosheets, respectively, as efficient electrocatalysts for H2 generation. NiMoSx/NF exhibits a superior catalytic activity to CuMoSx/CF in 0.5 m H2SO4 solution, as CuMoSx/CF requires overpotentials (η) of 213 and 275 mV to obtain current densities of 10 and 50 mA cm−2, respectively, whereas NiMoSx/NF only requires η of 174 and 248 mV to receive the same current densities, respectively. Furthermore, these electrodes exhibit considerable long-term electrochemical durability. Herein, an effective and easy-to-operate strategy for the construction of self-supported metal–molybdenum sulfide nanosheet arrays films toward a highly efficient electrochemical hydrogen generation reaction is provided.
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| 7. |
- Glodzik, Dominik, et al.
(författare)
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A somatic-mutational process recurrently duplicates germline susceptibility loci and tissue-specific super-enhancers in breast cancers
- 2017
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 49:3, s. 341-348
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Tidskriftsartikel (refereegranskat)abstract
- Somatic rearrangements contribute to the mutagenized landscape of cancer genomes. Here, we systematically interrogated rearrangements in 560 breast cancers by using a piecewise constant fitting approach. We identified 33 hotspots of large (>100 kb) tandem duplications, a mutational signature associated with homologous-recombination-repair deficiency. Notably, these tandem-duplication hotspots were enriched in breast cancer germline susceptibility loci (odds ratio (OR) = 4.28) and breast-specific 'super-enhancer' regulatory elements (OR = 3.54). These hotspots may be sites of selective susceptibility to double-strand-break damage due to high transcriptional activity or, through incrementally increasing copy number, may be sites of secondary selective pressure. The transcriptomic consequences ranged from strong individual oncogene effects to weak but quantifiable multigene expression effects. We thus present a somatic-rearrangement mutational process affecting coding sequences and noncoding regulatory elements and contributing a continuum of driver consequences, from modest to strong effects, thereby supporting a polygenic model of cancer development.
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| 8. |
- Ju, Young Seok, et al.
(författare)
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Frequent somatic transfer of mitochondrial DNA into the nuclear genome of human cancer cells.
- 2015
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Ingår i: Genome Research. - : Cold Spring Harbor Laboratory. - 1549-5469 .- 1088-9051. ; 25:6, s. 814-824
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Tidskriftsartikel (refereegranskat)abstract
- Mitochondrial genomes are separated from the nuclear genome for most of the cell cycle by the nuclear double membrane, intervening cytoplasm, and the mitochondrial double membrane. Despite these physical barriers, we show that somatically acquired mitochondrial-nuclear genome fusion sequences are present in cancer cells. Most occur in conjunction with intranuclear genomic rearrangements, and the features of the fusion fragments indicate that nonhomologous end joining and/or replication-dependent DNA double-strand break repair are the dominant mechanisms involved. Remarkably, mitochondrial-nuclear genome fusions occur at a similar rate per base pair of DNA as interchromosomal nuclear rearrangements, indicating the presence of a high frequency of contact between mitochondrial and nuclear DNA in some somatic cells. Transmission of mitochondrial DNA to the nuclear genome occurs in neoplastically transformed cells, but we do not exclude the possibility that some mitochondrial-nuclear DNA fusions observed in cancer occurred years earlier in normal somatic cells.
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| 9. |
- Li, Wei, et al.
(författare)
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Land-use and land-cover change carbon emissions between 1901 and 2012 constrained by biomass observations
- 2017
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 14:22, s. 5053-5067
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Tidskriftsartikel (refereegranskat)abstract
- The use of dynamic global vegetation models (DGVMs) to estimate CO2 emissions from land-use and land-cover change (LULCC) offers a new window to account for spatial and temporal details of emissions and for ecosystem processes affected by LULCC. One drawback of LULCC emissions from DGVMs, however, is lack of observation constraint. Here, we propose a new method of using satellite-and inventory-based biomass observations to constrain historical cumulative LULCC emissions (E-LUC(c)) from an ensemble of nine DGVMs based on emerging relationships between simulated vegetation biomass and E-LUC(c). This method is applicable on the global and regional scale. The original DGVM estimates of E-LUC(c) range from 94 to 273 PgC during 1901-2012. After constraining by current biomass observations, we derive a best estimate of 155 +/- 50 PgC (1 sigma Gaussian error). The constrained LULCC emissions are higher than prior DGVM values in tropical regions but significantly lower in North America. Our emergent constraint approach independently verifies the median model estimate by biomass observations, giving support to the use of this estimate in carbon budget assessments. The uncertainty in the constrained Ec LUC is still relatively large because of the uncertainty in the biomass observations, and thus reduced uncertainty in addition to increased accuracy in biomass observations in the future will help improve the constraint. This constraint method can also be applied to evaluate the impact of land-based mitigation activities.
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| 10. |
- Nik-Zainal, Serena, et al.
(författare)
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Landscape of somatic mutations in 560 breast cancer whole-genome sequences
- 2016
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 534:7605, s. 47-54
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Tidskriftsartikel (refereegranskat)abstract
- We analysed whole-genome sequences of 560 breast cancers to advance understanding of the driver mutations conferring clonal advantage and the mutational processes generating somatic mutations. We found that 93 protein-coding cancer genes carried probable driver mutations. Some non-coding regions exhibited high mutation frequencies, but most have distinctive structural features probably causing elevated mutation rates and do not contain driver mutations. Mutational signature analysis was extended to genome rearrangements and revealed twelve base substitution and six rearrangement signatures. Three rearrangement signatures, characterized by tandem duplications or deletions, appear associated with defective homologous-recombination-based DNA repair: one with deficient BRCA1 function, another with deficient BRCA1 or BRCA2 function, the cause of the third is unknown. This analysis of all classes of somatic mutation across exons, introns and intergenic regions highlights the repertoire of cancer genes and mutational processes operating, and progresses towards a comprehensive account of the somatic genetic basis of breast cancer.
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