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Graphical abstract Highlights • Degradation kinetics during XPS analysis exemplified for CaCrO 4. • Investigation of CaCrO 4 as a solid and incorporated in an organic binder matrix. • Presence of organic compounds accelerates reduction to Cr(III). • Cooling during XPS analysis improves the chemical stability. • Results provide a basis for a reliable quantification of Cr(VI) by XPS. Abstract Chromium compounds are still used in the context of corrosion protection in industrial products, with Cr containing organic coatings on electrical steel as an example. In order to analyse the content of hazardous Cr(VI) components, X-ray photoelectron spectroscopy (XPS) is often promoted as a non-destructive technique which enables the determination of elemental concentrations and chemical states. However, this technique can affect the oxidation state as we show for CaCrO 4. The key point is that pure Cr reference materials behave differently as compared to mixed material systems, which has to be considered for a reliable quantification of Cr(VI) by XPS. [ABSTRACT FROM AUTHOR]

We set out to demonstrate the development of a highly conductive polymer based on poly-(3,4-ethylenedithia thiophene) (PEDTT), PEDOTs structural analogue historically notorious for structural disorder and limited conductivities. The caveat therein was previously described to lie in intra-molecular repulsions. We demonstrate how a tremendous >2600-fold improvement in conductivity and metallic features, such as magnetoconductivity can be achieved. This is achieved through a careful choice of the counter-ion (sulphate) and the use of oxidative chemical vapour deposition (oCVD). It is shown that high structural order on the molecular level was established and the formation of crystallites tens of nanometres in size was achieved. We infer that the sulphate ions therein intercalate between the polymer chains, thus forming densely packed crystals of planar molecules with extended π-systems. Consequently, room-temperature conductivities of above 1000 S cm -1 are achieved, challenging those of conventional PEDOT:PSS. The material is in the critical regime of the metal-insulator transition., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2021 The Author(s). Published by National Institute for Materials Science in partnership with Taylor & Francis Group.)

The most active and efficient catalysts for the electrochemical hydrogen evolution reaction (HER) rely on platinum, a fact that increases the cost of producing hydrogen and thereby limits the widespread adoption of this fuel. Here, a metal-free organic electrocatalyst that mimics the platinum surface by implementing a high work function and incorporating hydrogen-affine hydrogen bonds is introduced. These motifs, inspired from enzymology, are deployed here as selective reaction centres. It is shown that the keto-amine hydrogen-bond motif enhances the rate-determining step in proton reduction to molecular hydrogen. The keto-amine-functionalized polymers reported herein evolve hydrogen at an overpotential of 190 mV. They share certain key properties with platinum: a similar work function and excellent electrochemical stability and chemical robustness. These properties allow the demonstration of one week of continuous HER operation without notable degradation nor delamination from the carrier electrode. Scaled continuous-flow electrolysis is reported and 1 L net molecular hydrogen is produced within less than 9 h using 2.3 mg of polymer electrocatalyst., (© 2020 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Selective electrocatalysts are urgently needed for carbon dioxide (CO 2 ) reduction to replace fossil fuels with renewable fuels, thereby closing the carbon cycle. To date, noble metals have achieved the best performance in energy yield and faradaic efficiency and have recently reached impressive electrical-to-chemical power conversion efficiencies. However, the scarcity of precious metals makes the search for scalable, metal-free, CO 2 reduction reaction (CO 2 RR) catalysts all the more important. We report an all-organic, that is, metal-free, electrocatalyst that achieves impressive performance comparable to that of best-in-class Ag electrocatalysts. We hypothesized that polydopamine-a conjugated polymer whose structure incorporates hydrogen-bonded motifs found in enzymes-could offer the combination of efficient electrical conduction, together with rendered active catalytic sites, and potentially thereby enable CO 2 RR. Only by developing a vapor-phase polymerization of polydopamine were we able to combine the needed excellent conductivity with thin film-based processing. We achieve catalytic performance with geometric current densities of 18 mA cm -2 at 0.21 V overpotential (-0.86 V versus normal hydrogen electrode) for the electrosynthesis of C 1 species (carbon monoxide and formate) with continuous 16-hour operation at >80% faradaic efficiency. Our catalyst exhibits lower overpotentials than state-of-the-art formate-selective metal electrocatalysts (for example, 0.5 V for Ag at 18 mA cm -1 ). The results confirm the value of exploiting hydrogen-bonded sequences as effective catalytic centers for renewable and cost-efficient industrial CO 2 RR applications.