Technical University of Berlin

About: Technical University of Berlin is a education organization based out in Berlin, Germany. It is known for research contribution in the topics: Laser & Catalysis. The organization has 27292 authors who have published 59342 publications receiving 1414623 citations. The organization is also known as: Technische Universität Berlin & TU Berlin.

Origin of the Breit-Wigner-Fano lineshape of the tangential G-band feature of metallic carbon nanotubes

Abstract: A detailed line-shape analysis of the tangential G-band feature attributable to metallic single-walled carbon nanotubes is presented. Only two components are needed to account for the entire G-band feature for metallic nanotubes. The higher-frequency component has a Lorentzian line shape, and the lower one has a Breit-Wigner-Fano (BWF) line shape. Through comparisons of the Raman tangential G-band spectra from three different diameter distributions of carbon nanotubes, we find that both the frequency and linewidth of the BWF component are diameter dependent and show functional forms consistent with theory. The nanotube curvature is responsible for both the frequency differences between the two components of the characteristic metallic G-band spectrum and the BWF coupling of the lower-frequency component. Surface-enhanced Raman spectroscopy studies provide supporting evidence that the phonon BWF coupling is to an electronic continuum.

Molecular Insight in Structure and Activity of Highly Efficient, Low-Ir Ir–Ni Oxide Catalysts for Electrochemical Water Splitting (OER)

Abstract: Mixed bimetallic oxides offer great opportunities for a systematic tuning of electrocatalytic activity and stability. Here, we demonstrate the power of this strategy using well-defined thermally prepared Ir–Ni mixed oxide thin film catalysts for the electrochemical oxygen evolution reaction (OER) under highly corrosive conditions such as in acidic proton exchange membrane (PEM) electrolyzers and photoelectrochemical cells (PEC). Variation of the Ir to Ni ratio resulted in a volcano type OER activity curve with an unprecedented 20-fold improvement in Ir mass-based activity over pure Ir oxide. In situ spectroscopic probing of metal dissolution indicated that, against common views, activity and stability are not directly anticorrelated. To uncover activity and stability controlling parameters, the Ir–Ni mixed thin oxide film catalysts were characterized by a wide array of spectroscopic, microscopic, scattering, and electrochemical techniques in conjunction with DFT theoretical computations. By means of an in...

Octahedral PtNi nanoparticle catalysts: exceptional oxygen reduction activity by tuning the alloy particle surface composition.

Abstract: We demonstrate how shape selectivity and optimized surface composition result in exceptional oxygen reduction activity of octahedral PtNi nanoparticles (NPs). The alloy octahedra were obtained by utilizing a facile, completely surfactant-free solvothermal synthesis. We show that the choice of precursor ligands controls the shape, while the reaction time tunes the surface Pt:Ni composition. The 9.5 nm sized PtNi octahedra reached a 10-fold surface area-specific (∼3.14 mA/cmPt2) as well as an unprecedented 10-fold Pt mass based (∼1.45 A/mgPt) activity gain over the state-of-art Pt electrocatalyst, approaching the theoretically predicted limits.

Connectivity Predicts deep brain stimulation outcome in Parkinson disease.

Abstract: Objective: The benefit of deep brain stimulation (DBS) for Parkinson's disease (PD) may depend on connectivity between the stimulation site and other brain regions, but which regions and whether connectivity can predict outcome in patients remains unknown. Here, we identify the structural and functional connectivity profile of effective DBS to the subthalamic nucleus (STN) and test its ability to predict outcome in an independent cohort. Methods: A training dataset of 51 PD patients with STN DBS was combined with publicly available human connectome data (diffusion tractography and resting state functional connectivity) to identify connections reliably associated with clinical improvement (motor score of Unified Parkinson's Disease Rating Scale). This connectivity profile was then used to predict outcome in an independent cohort of 44 patients from a different center. Results: In the training dataset, connectivity between the DBS electrode and a distributed network of brain regions correlated with clinical response including structural connectivity to supplementary motor area and functional anticorrelation to primary motor cortex (p < 0.001). This same connectivity profile predicted response in an independent patient cohort (p < 0.01). Structural and functional connectivity were independent predictors of clinical improvement (p < 0.001) and estimated response in individual patients with an average error of 15% UPDRS improvement. Results were similar using connectome data from normal subjects or a connectome age, sex, and disease-matched to our DBS patients. Interpretation: Effective STN-DBS for PD is associated with a specific connectivity profile that can predict clinical outcome across independent cohorts. This prediction does not require specialized imaging in PD patients themselves. This article is protected by copyright. All rights reserved.