Engelbert Portenkirchner

University of Innsbruck | UIBK · Institute of Physical Chemistry

The organic semiconductor 3,4,9,10-perylenetetra-carboxylic diimide (PTCDI), a widely used industrial pigment, has been identified as a diffusion-less Na-ion storage material, allowing for exceptionally fast charging/discharging rates. The elimination of diffusion effects in electrochemical measurements enables the assessment of interaction energie...

The compound material titanium oxycarbide (TiOC) is found to be an effective electrocatalyst for the electrochemical oxidation of ethanol to CO2. The complete course of this reaction is one of the main challenges in direct ethanol fuel cells (DEFCs). While TiOC has previously been investigated as catalyst support material only, in this study we sho...

For the direct reduction of CO2 and H2O in solid oxide electrolysis cells (SOECs) with cermet electrodes toward methane, a fundamental understanding of the role of elemental carbon as a key intermediate within the reaction pathway is of eminent interest. The present synchrotron-based in situ near-ambient-pressure X-ray photoelectron spectroscopy (N...

NaTi2(PO4)3 (NTP) is known as a promising insertion‐type anode material for aqueous and non‐aqueous sodium‐ion batteries (SIBs), due to its NASICON‐type open 3D framework which makes a zero‐strain insertion mechanism possible. NTP is considered to be an environmentally friendly, low‐cost and high safety material. However, the electrochemical perfor...

For the direct reduction of CO2 and H2O in solid oxide electrolysis cells (SOECs) with cermet electrodes toward methane, a fundamental understanding of the role of elemental carbon as a key intermediate within the reaction pathway is of eminent interest. The present synchrotron-based in situ near-ambient-pressure X-ray photoelectron spectroscopy (N...

A versatile multifunctional laboratory-based near ambient pressure x-ray photoelectron spectroscopy (XPS) instrument is presented. The entire device is highly customized regarding geometry, exchangeable manipulators and sample stages for liquid- and solid-state electrochemistry, cryochemistry, and heterogeneous catalysis. It therefore delivers nove...

A profound understanding of the solid/liquid interface is central in electrochemistry and electrocatalysis, as the interfacial properties ultimately determine the electro‐reactivity of a system. Although numerous electrochemical methods exist to characterize this interface under operating conditions, tools for the in‐situ observation of the surface...

NaTi2(PO4)3 (NTP) and Na0.44MnO2 (NMO), and their derivatives, have emerged as the most promising materials for aqueous Na-ion batteries. For both, NTP and NMO, avoiding the evolution of hydrogen and oxygen is found to be mandatory in order to mitigate material dissolution. Intriguingly, however, no direct determination of the hydrogen and oxygen e...

Batteries and supercapacitors, both governed by electrochemical processes, operate by different electrochemical mechanisms which determine their characteristic energy and power densities. Battery materials store large amounts of energy by ion intercalation. Electrical double-layer capacitors store charge through surface-controlled ion adsorption wh...

Excellent, self‐improving sodiation rate capabilities in combination with high capacity retention upon galvanostatic charge/discharge cycling are found for oxygen‐deficient, carburized, and self‐organized titanium dioxide (TiO2−x) nanotubes (NTs). The sodiation mechanism is attributed to the formation of an acicular surface film as the active stora...

Electrochemical capture of carbon dioxide (CO2) using organic quinones is a promising and intensively studied alternative to the industrially established scrubbing processes. While recent studies focused only on the influence of substituents having a simple mesomeric or nucleophilicity effect, we have systematically selected six anthraquinone (AQ)...

Anthraquinone (AQ) has long been identified as a highly promising lead structure for various applications in organic electronics. Considering the enormous number of possible substitution patterns of the AQ lead structure, with only a minority being commercially available, a systematic experimental screening of the associated electrochemical potenti...

Electroactive organic semiconducting pigments represent a group of very promising electrode materials for the next generation of energy conversion and storage technologies. However, most pigments suffer from high solubility in organic electrolytes and poor electrical conductivity , which have severely impeded their practical applications. Among dif...

The ordering effects in anthraquinone (AQ) stacking forced by thin-film application and its influence on dimer solubility and current collector adhesion are investigated. The structural characteristics of AQ and its chemical environment are found to have a substantial influence on its electrochemical performance. Computational investigation for dif...

Long term galvanostatic charge/discharge cycling of oxygen deficient, carburized and self‐organized titanium dioxide (TiO2) nanotubes (NTs) in sodium ion (Na) batteries (SIBs) are subject to a significant self‐improving charge storage behavior. Surface reactions upon sodiation of carburized NTs form acicular surface films that can be reversibly cyc...

In this work 3,4,9,10‐perylenetetracarboxylic diimide (PTCDI) is investigated as electrode material for organic Na‐ion batteries. Since PTCDI is a widely used industrial pigment, it may turn out to be a cost‐effective, abundant, and environmentally benign cathode material for secondary Na‐ion batteries. Among other carbonyl pigments, PTCDI is espec...

Developing sodium (Na) ion batteries is highly appealing, because they offer the potential to be made from raw materials which hold the promise to be less expensive, less toxic and at the same time more abundant compared to state-of-the-art lithium (Li) ion batteries. In this work the Na ion storage capability of nanostructured organic-inorganic po...

We report the synthesis and electrochemical properties of freebase tetraphenyltetrabenzoporphyrin and its complexes of Zn(ii), Co(ii), Ni(ii), Cu(ii) and Sn(iv) towards electrochemical reduction of carbon dioxide (CO2). Based on cyclic voltammetry, it is shown that central metals significantly affect the electrocatalytic performance in the reductio...

The Front Cover illustrates the concept of an all‐organic sodium‐ion battery, with n‐type organics as both the cathode and anode. The two‐electron redox reaction of anthraquinone in a sodium electrolyte system is depicted in the background. This reaction is exploited to fabricate an anthraquinone/carbon fiber composite cathode material for recharge...

The transition from rare to natural abundant materials in rechargeable batteries is becoming a grand challenge in developing a resource sustainable power supply. Since decades scientists attempt to circumvent the lithium's resource problem by innovating alternative active metal ions. A cost‐effective alternative to lithium is to use sodium as the c...

X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy are used to investigate the electrochemical lithiation/ delithiation behavior of self-organized amorphous titanium dioxide (TiO2) and anatase TiO2-x nanotubes. The bulk lithiation properties are governed by the different phase transitions in amorphous and anatase TiO2. Whil...

We report on a self-assembled system comprising a molecular copper-porphyrin photoelectrocatalyst, 5-(4-carboxy-phenyl)-10,15,20-triphenylporphyrinatocopper(II) (CuTPP-COOH), covalently bound to self-organized, anodic titania nanotube arrays (TiO2 NTs) for photoelectrochemical reduction of oxygen. Visible light irradiation of the porphyrin-covered...

The Cover Feature illustrates the consequences of CO2 release into the atmosphere from man-made sources. With humanity re-emitting, within a couple of decades, large amounts of CO2 that was fixated in millions of years though natural photosynthesis, there is a clear need for cyclic usage of CO2 to create a sustainable future employing photo- and bi...

X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy are used to investigate the electrochemical lithiation/delithiation behaviour of self-organized amorphous TiO2 and anatase TiO2-x nanotubes. With proceeding bulk lithiation of the active material, surface films form on both nanotube arrays. Carbonates start forming with the...

Self-organized TiO2 nanotubes (NTs) with a preferential orientation along the [001] direction are anodically grown by controlling the water content in the fluoride containing electrolyte. The intrinsic kinetic and thermodynamic properties of the Li intercalation process in the preferentially oriented (PO) TiO2 NTs and in a randomly oriented (RO) Ti...

Hybrid Microbial Fuel Cell: The cover art depicts positive lithium ions that flow towards the silicon nanoparticles, where these nanoparticles expand during the lithiation process. Silicon has attracted great attention as a promising anode material for lithium-ion batteries due to its exceptionally high theoretical specific capacity. Despite these...

Silicon (Si) is considered one of the most promising electrode materials for next generation high energy density lithium-ion batteries, demonstrating an exceptionally high specific capacity with an order of magnitude beyond that of conventional graphite. The poor capacity retention, caused by mechanical fracturing of Si due to extreme volumetric an...

A broad overview on homogeneous and heterogeneous catalytic approaches using organic, organometallic and bioorganic systems towards CO2 reduction is reviewed. Electrochemical, bioelectrochemical and photoelectrochemical approaches are discussed in terms of their faradaic efficiencies, overpotentials and reaction mechanisms. The organometallic compl...

Developing efficient methods for capture and controlled release of carbon dioxide is crucial to any carbon capture and utilization technology. Herein we present an approach using an organic semiconductor electrode to electrochemically capture dissolved CO2 in aqueous electrolytes. The process relies on electrochemical reduction of a thin film of a...

Nanostructuring of electrode materials is a promising approach to enhance the performance of next generation high energy density lithium (Li) -ion batteries. Various experimental and theoretical approaches allow for detailed understanding of solid-state or surface controlled reactions that occur in nanoscaled electrode materials. While most techniq...

Third-generation polythiophenes, bearing Rhenium carbonyl complexes and pyridinium as pendant active sites were used to drive the photoelectrochemical reduction of CO2. Cyclic voltammetry and controlled potential electrolysis experiments were performed in CO2-saturated acetonitrile, acetonitrile-water and aqueous solutions under illumination as wel...

We present results for direct bio-electrocatalytic reduction of CO2 to C1 products using electrodes with immobilized enzymes. Enzymatic reduction reactions are well known from biological systems where CO2 is selectively reduced to formate, formaldehyde, or methanol at room temperature and ambient pressure. In the past, the use of such enzymatic red...

Since several years, research for high capacity anode materials in Li-ion batteries is addressed to titanium dioxide (TiO2), which offers important advantages in terms of cost effectiveness, safety and environmental compatibility. This work reports on the lithiation and delithiation characteristics of anodically grown, self-organized TiO2 nanotubes...

Sol-gel processed copper indium sulfide (CIS) films have been processed on glass and transparent indium doped tin oxide (ITO)-coated glass electrodes by a straightforward layer by layer spin coating route yielding excellent film qualities with subsequent thermal annealing. Resulting films were characterized using X-ray diffraction (XRD), scanning e...

Titanium oxide–titanium carbide (TiOxCy) hybrid materials have tunable electronic properties ranging from semiconductive to semimetallic. They can therefore be employed in solar energy conversion applications and as potential substitute for carbon based electrocatalyst supports for use in fuel cells. Understanding of the optical properties of semim...

Correction for 'Oxygen deficient, carbon coated self-organized TiO2 nanotubes as anode material for Li-ion intercalation' by J. Brumbarov et al., J. Mater. Chem. A, 2015, 3, 16469-16477.

The current energy supply of human society is based on fossil fuels like coal, oil and gas which are related to several problems. The reserves are decreasing and their final depletion seems to be just a matter of time. Several approaches have been made to replace fossil fuels by sustainable techniques. Up to now none of these were able to fully rep...

The synthesis, structure, photophysics, and spectroscopic characterization of a organometallic rhenium multichromophore compound carrying a central 2,2’-bipyridyl acceptor moiety with additional phenylethynyl substituents conjugated at the 4,4´-positions of the acceptor ligands and its effect on the electron density of the central rhenium atom as m...

The electrocatalytic reduction of CO2 to methanol is explored by the direct comparison of protonated pyridazine and pyridine for their capabilities towards CO2 reduction. The two materials inherit a significant difference in their pKa values adding valuable information to the ongoing discussion on the nature of CO2 reduction catalyzed by pyridinium...

This work investigates the photoinduced energy transfer from poly(N-vinylcarbazole) (PVK), as a donor material, to fac-(2,2′-bipyridyl)Re(CO)3Cl, as a catalyst acceptor, for its potential application towards CO2 reduction. Photoluminescence quenching experiments reveal dynamic quenching through resonance energy transfer in solid donor/acceptor mixt...

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Die Speicherung, Abtrennung und Nutzung von Kohlendioxid ist ein aktuelles und intensiv bearbeitetes Forschungsgebiet. In dieser Studie wird die kontrollierte Speicherung und Freisetzung von CO2 mithilfe eines industriellen Farbstoffs, Chinacridon, beschrieben. Eine elektrochemisch reduzierte Elektrode bestehend aus einem Chinacridonfilm (ca. 100 n...

Limiting anthropogenic carbon dioxide emissions constitutes a major issue faced by scientists today. Herein we report an efficient way of controlled capture and release of carbon dioxide using nature inspired, cheap, abundant and non-toxic, industrial pigment namely, quinacridone. An electrochemically reduced electrode consisting of a quinacridone...

A series of rhenium(I) carbonyl chloride complexes carrying bis(imino)acenaphthene (BIAN) molecules as pi-acceptor ligands was prepared and characterized by various spectroscopic techniques. Among the novel compounds described, the remarkable example of a deeply colored water-soluble rhenium carbonyl derivative is presented. The crystal structures...

elisa.tordin@gmail.com The electrochemical reduction of carbon dioxide has been subject of a great deal of interests in the past decades since it could be an efficient way to convert this greenhouse gas into valuable chemicals and fuel. This process is quite energetically inefficient since a high overpotential required to convert carbon dioxide to...

Rhenium(I) carbonyl complexes carrying substituted bis(arylimino)acenaphthene ligands (BIAN-R) have been tested as potential catalysts for the two-electron reduction of carbon dioxide. Cyclic voltammetric studies as well as controlled potential electrolysis experiments were performed using CO2-saturated solutions of the complexes in acetonitrile an...

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We present two laser ultrasonic receivers based on organic photorefractive polymer composites with 2-[4-bis(2-methoxyethyl)aminobenzylidene]malononitrile (AODCST) or 2-dicyanomethylen-3-cyano-5,5-dimethyl-4-(4′-dihexylaminophenyl)-2,5-dihydrofuran nonlinear optical chromophores. Experimental results show sensitivities of the ultrasonic receivers of...

The alkynyl-substituted Re(I) complex [Re(5,5'-bisphenylethynyl-2,2'-bipyridyl)(CO)3Cl] was immobilized by electropolymerization onto a Pt-plate electrode. The polymerized film exhibited electrocatalytic activity for the reduction of CO2 to CO. Cyclic voltammetry studies and bulk controlled-potential electrolysis experiments were performed by using...

Rhenium and rhodium complexes with bipyridyl ligands have been proven to be efficient homogeneous catalystsin the field of carbon dioxide and proton reduction. In this work, the authors provide several examples of thesecompounds with modified ligand structures and discuss their electro- and photo-catalytic capabilities toward carbon dioxide reducti...

The rhenium complex fac-(5,5′-bisphenylethynyl-2,2′-bipyridyl)Re(CO)3Cl was used as a novel catalyst for the electro- and photochemical reduction of CO2 to CO in homogeneous solution. The results were compared to (2,2′-bipyridyl)Re(CO)3Cl as a benchmark compound. Cyclic voltammetric studies as well as bulk controlled potential electrolysis experime...