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Catalytic hydrogenation and oxidative dehydrogenation of N‐heterocycles to produce tetrahydroquinoline and quinoline derivatives are important reactions of particular importance in the agrochemical and pharmaceutical industries. Herein, we report earth‐abundant cobalt nanoparticles supported on hydroxyapatite (HAP) as an inexpensive and efficient catalyst for the hydrogenation and reverse oxidative dehydrogenation of N‐heterocycles. The optimal nanocatalyst exhibits excellent activity in both reactions for a wide range of substrates including (iso)quinolines, acridine, benzo[h]quinoline, quinoxaline and indole. Reactions proceed under relatively mild conditions without requiring any additives. [ABSTRACT FROM AUTHOR]

A heterogeneous single‐atom catalyst (SAC) based on a tiny Cu loading (0.05 wt.%) supported on CeO2−TiO2 (Ce/Ti=0.18) shows very high Cu mass‐normalized CO oxidation activity, 100 % selectivity for CO2 between 60 and 100 °C and essentially no deactivation during 17 h on stream in the preferential oxidation of CO (PROX) at 120 °C. Based on state of the art, this catalyst is among the most active and PROX‐selective catalysts. Employing a combination of ex‐situ and operando methods, we infer that the isolated Cu single sites are incorporated with redox‐active Cu2+−O−Ce4+⇆Cu+−□−Ce3+ moieties connected by labile oxygen and are exposed on the surface of highly dispersed ceria. This high dispersion is promoted by TiO2 which itself does not participate in redox steps during PROX, as Ti ions remain essentially tetravalent while Cu and Ce undergo reversible redox shuttles. [ABSTRACT FROM AUTHOR]

Highly active and coking‐resistant Ni catalysts suited for the dry reforming of CH4‐rich gases (70 vol %, e. g. biogas or sour natural gas) were prepared starting from a Mg‐rich Mg−Al hydrotalcite support precursor. Calcination at 1000 °C yields two phases, MgO and MgAl2O4 spinel. Complexation‐deposition of Ni with citric acid on the preformed support as well as lanthanum addition yields a catalyst with remarkably low carbon accumulation over 100 h on stream attributed to both high Ni dispersion and preferred interactions of Ni with MgO on MgAl2O4. [ABSTRACT FROM AUTHOR]

A heterogeneous single‐atom catalyst (SAC) based on a tiny Cu loading (0.05 wt.%) supported on CeO2−TiO2 (Ce/Ti=0.18) shows very high Cu mass‐normalized CO oxidation activity, 100 % selectivity for CO2 between 60 and 100 °C and essentially no deactivation during 17 h on stream in the preferential oxidation of CO (PROX) at 120 °C. Based on state of the art, this catalyst is among the most active and PROX‐selective catalysts. Employing a combination of ex‐situ and operando methods, we infer that the isolated Cu single sites are incorporated with redox‐active Cu2+−O−Ce4+⇆Cu+−□−Ce3+ moieties connected by labile oxygen and are exposed on the surface of highly dispersed ceria. This high dispersion is promoted by TiO2 which itself does not participate in redox steps during PROX, as Ti ions remain essentially tetravalent while Cu and Ce undergo reversible redox shuttles. [ABSTRACT FROM AUTHOR]