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Hydrodehalogenation is astraightforwardapproach for detoxifications of harmful anthropogenic organohalidebased pollutants,aswell as removal of halide protecting groups used in multistep syntheses.An ovel sustainable catalytic material was prepared from biowaste (chitosan) in combination with an earth-abundant cobalt salt. The heterogeneous catalyst was fully characterized by transmission electron microscope,X -rayd iffraction, and X-ray photoelectron spectroscopym easurements,a nd successfully applied to hydrodehalogenation of alkyla nd (hetero)aryl halides with broad scope (> 40 examples) and excellent chemoselectivity using molecular hydrogen as ar eductant. The general usefulness of this method is demonstrated by successful detoxification of non-degradable pesticides and fire retardants.M oreover,t he potential of the catalyst as adeprotection tool is demonstrated in am ultistep synthesis of (AE)-peronatin B( alkaloid).Hydrodehalogenation constitutes an important organic transformation where ahalogen atom is formally substituted with ahydrogen atom. It has become an enabling technology for degradation of anthropogenic and environmentally deleterious chemicals into their less noxious congeners.T he former are often produced in industrial processes and can include polyhalogenated organic pollutants (such as,p olychlorodioxins and polychlorophenols), toxic and persistent pesticides,and fire retardants. [1,2] Furthermore,hydrodehalogenation reactions are often used in organic synthesis for deprotection chemistry,s ince halides can selectively block one of two reaction sites with similar reactivity without strongly influencing the electronics of the system. [2,3] Additionally,s tereoselective hydrodehalogenation of prochiral gem-dihalo-organic compounds affords chiral halo-organic compounds. [4] Hydrodehalogenation reactions have been performed with various methods,s uch as metal-halogen exchange, [2, 5] metal-mediated reduction, [2,6] photochemical reduction, [7] and reductive radical dehalogenation. [8] Some of these reactions are marred by the use of toxic and explosive reagents, production of stoichiometric metal waste,poor selectivity,and low functional-group tolerance.Nevertheless,there has been an intense research interest in developing more efficient and reliable transition-metal-catalyzed hydrodehalogenation processes (mostly involving,Pd, [9] Rh, [10] Ru, [11] Ni, [4,12] and Fe [13] ) using Grignard reagents, [12c,13] alcohol and base, [9a, 10c, 11a,c] hydrides, [4,9b,c, 12b,d,14] formic acid [9h] or its salt, [9e] hydrazine, [9d] and molecular hydrogen. [9c,f,g,10a,b, 11b,12a] Obviously,f rom an ecological perspective,t he later reagent is considered to be the most efficient, clean, and atom-economical reductant. [15] Fort he last decade,t he implementation of cheap,e arth abundant, non-noble metals for (de)hydrogenation reactions has attracted significant interest in homogeneous and heterogeneous catalysis. [16] As acomplement to molecularly defined organometallic complexes,heterogeneous mat...

Efficient water electrolysis requires highly active electrodes. The activity of corresponding catalytic coatings strongly depends on material properties such as film thickness, crystallinity, electrical conductivity, and chemical surface speciation. Measuring these properties with high accuracy in vacuum-free and nondestructive methods facilitates the elucidation of structure−activity relationships in realistic environments. Here, we report a novel approach to analyze the optical and electrical properties of highly active oxygen evolution reaction (OER) catalysts via spectroscopic ellipsometry (SE). Using a series of differently calcined, mesoporous, templated iridium oxide films as an example, we assess the film thickness, porosity, electrical resistivity, electron concentration, electron mobility, and interband and intraband transition energies by modeling of the optical spectra. Independently performed analyses using scanning electron microscopy, energy-dispersive X-ray spectroscopy, ellipsometric porosimetry, X-ray reflectometry, and absorption spectroscopy indicate a high accuracy of the deduced material properties. A comparison of the derived analytical data from SE, resonant photoemission spectroscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy with activity measurements of the OER suggests that the intrinsic activity of iridium oxides scales with a shift of the Ir 5d t 2g sub-level and an increase of p−d interband transition energies caused by a transition of μ 1 -OH to μ 3 -O species.

The following work presents the preparation and investigation of pyrolysed Co-porphyrine as an electrocatalyst for the oxygen reduction reaction (ORR) in acid media. A new preparation method which needs no addition of carbon supports, allows the structural investigation of the pyrolysis products by XPS, Raman spectroscopy and X-ray diffractometry without any interferences. Rotating Disc Electrode measurements reveal the high ORR activity which is mainly caused by a well developed porosity and a suitable molecular structure of the formed carbon. Thermogravimetric investigation of the pyrolysis process shows that the addition of sulphur influences the carbonization of the porphyrine in a favorable way. It has been found that extended graphene layers present a particularly suitable matrix for highly active catalytic centers.

Mussel‐inspired polydopamine (PDA) initiates a multifunctional modification route that leads to the generation of novel advanced materials and their applications. However, existing PDA deposition techniques still exhibit poor spatial control, have a very limited capability of micropatterning, and do not allow local tuning of the PDA topography. Herein, PDA deposition based on multiphoton lithography (MPL) is demonstrated, which enables full spatial and temporal control with nearly total freedom of patterning design. Using MPL, 2D microstructures of complex design are achieved with pattern precision of 0.8 µm without the need of a photomask or stamp. Moreover, this approach permits adjusting the morphology and thickness of the fabricated microstructure within one deposition step, resulting in a unique tunability of material properties. The chemical composition of PDA is confirmed and its ability for protein enzyme immobilization is demonstrated. This work presents a new methodology for high‐precision and complete control of PDA deposition, enabling PDA incorporation in applications where fine and precise local surface functionalization is required. Possible applications include multicomponent functional elements and devices in microfluidics or lab‐on‐a‐chip systems.