The use of earth-abundant transition metals as a noble metal replacement in catalysis is especially interesting if different catalytic reactivity is observed. We report, here, on the selective manganese-catalyzed base-switchable synthesis of N-alkylated amines or imines. In both reactions, borrowing hydrogen/hydrogen autotransfer (N-alkyl amine formation) or dehydrogenative condensation (imine formation), we start from the same amines and alcohols and use the same Mn precatalyst. The key is the presence of a potassium base to prefer N-alkylation and a sodium base to permit imine formation. Both bases react with the manganese hydride via deprotonation. The potassium manganate hydride reacts about 40 times faster with an imine to give the corresponding amine than the sodium manganate hydride. The selectivity seems unique for manganese complexes. We observe a broad scope with a complete product overlap, all amine alcohol combinations can be converted into an N-alkyl amine or an imine, and a good functional group tolerance.

Ammonia is not only the most important chemical for fertilizer production, it has also gained much interest as a future hydrogen storage material. Besides the well‐known Haber–Bosch process to generate ammonia from elemental sources, new ways to convert nitrogen into ammonia have been investigated in the last decade for a decentralized production, including electrocatalytic and photocatalytic approaches. However, photocatalysis in particular suffers from stagnating materials development and unstandardized reaction conditions. In this Review, we shine light on recent materials and reaction engineering results for photocatalytic nitrogen reduction, putting an emphasis on the need to connect the activity of reported materials together with detailed reaction conditions and efficiencies. Photocatalytic nitrogen reduction is an emerging field that will certainly gain significant interest in the future as a sustainable pathway to generate green hydrogen and ammonia. The field will certainly strongly benefit from joint efforts with strong interactions between chemists, physicists and chemical engineers at a fundamental level.

Phase-pure spinel Ni2FeS4 nanosheets with a specific surface area of 80 m2 g–1 were successfully prepared via fast and energy-saving microwave-assisted nonaqueous sol–gel synthesis, starting from metal acetylacetonates and benzyl mercaptan as the sulfur source. Synthesized nanosheets were characterized thoroughly by X-ray diffraction including Rietveld refinement, X-ray photoelectron spectroscopy, energy-dispersive X-ray spectroscopy, electron microscopy, nitrogen and water vapor physisorption measurements, and thermogravimetric analysis coupled with mass spectrometry. Such noble metal free Ni2FeS4 nanosheets were successfully applied as electrocatalyst for the aqueous carbon dioxide reduction reaction, yielding selectively the syngas components hydrogen and carbon monoxide.

Nanoparticles of cubic CuFe2O4 are obtained in a fast microwave‐assisted hydrothermal synthesis. By adjusting the pH value and solvent ratio (ethylene glycol to water), phase purity and high crystallinity is achieved at very short reaction times of 1 min, or low temperatures of 120 °C, without the need for subsequent heat treatment steps. The influence of the synthesis time or temperature on material properties and performance in electrochemical CO2 reduction to CO are investigated. While particle size and crystallinity are not changed significantly with longer synthesis times at 175 °C, prolonged heating results in a decrease of the degree of inversion, which leads to a decrease in the CO2 reduction ability. The best performance is observed for CuFe2O4 with an intermediate degree of inversion of approx. 0.75, together with the largest crystallite size and micro‐strain, as revealed by Rietveld refinement. For CuFe2O4 synthesized under these conditions, a CO evolution rate of 0.2 μmol h−1 g−1 is obtained at a Faradaic efficiency of 20%. The CO to H2 ratio is 1:3, which makes it a promising candidate for a sustainable production of syngas.

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