Electrophilic halocyclizations of olefins are an important class of transformations that can afford various useful halogenated cyclic molecules. In particular, the domino asymmetric electrophilic halocyclization is viable for synthesis of polycyclic pharmaceutical compounds. However, it remains limited to the generation of fused rings. Now, Yeung et al. demonstrate the catalytic enantioselective domino halocyclization and spiroketalization to give halo-spiroketals. Mechanistic studies reveal that the reaction is likely to proceed via a double dynamic kinetic resolution mechanism.

See Zheng et al.

Analogous with a modern production line, the cover image illustrates how precise placement of different active sites (robotic arms) within a hierarchical pore network enables individual catalyst particles to perform a complex sequence of chemical transformations in a cooperative and predictable process reminiscent of substrate channelling (conveyor belt) in biological systems. Here, the authors illustrate this approach for cascade and antagonistic reactions, namely a two-step deacetalization–Knoevenagel condensation of dimethyl acetals to cyanoates and a base-catalysed triacylglyceride transesterification.

See Isaacs et al.

Electrocatalysts for low-temperature fuel cells often consist of precious elements, e.g. platinum, which are expensive or not readily available. Now, Kunze-Liebhäuser et al. demonstrate the ability of Earth-abundant Cu to efficiently electro-oxidize CO, a central fuel cell intermediate, through continuous surface structure changes. Cu clusters reversibly form and show optimum binding to reaction intermediates, resembling the harpooning-type mechanism in gas–solid catalysis and drawing parallels between heterogeneous thermal catalysis and heterogeneous electrocatalysis.

See Kunze-Liebhäuser et al.

Lin and co-workers demonstrate that the performance degradation of mixed Ni–Fe hydroxide water oxidation electrocatalysts is due to their segregation into NiOOH and FeOOH phases. The authors find that this process is reversible between the water oxidation and catalyst reduction potentials, and show that the degraded electrocatalysts can be revivified under catalytic operating conditions via an intermittent reduction protocol.

See Lin et al.

Kim and co-workers demonstrate a HOR-selective electrocatalytic process imparted by a metal–insulator transition to mitigate degradation of the cathode catalyst layer during start-up/shut-down of PEMFCs for automotive applications. Platinum nanoparticles supported on hydrogen tungsten bronze (Pt/H x WO3) suppressed the ORR with a metal–insulator transition under exposure to oxygen, while selectively promoting the HOR by regaining metallic conductivity under exposure to hydrogen.

See Kim et al.

Photocatalysis with plasmonic metal nanostructures is an enabling technology for more sustainable chemical transformations. This cover illustration depicts plasmonic hydrodefluorination based on aluminium nanocrystal-supported palladium islands for the effective activation of unsaturated carbon–fluorine bonds in fluoromethane in the presence of deuterium gas. The contribution of photogenerated hot carriers to regenerating the palladium active sites via deuterium desorption leads to enhanced reactivity under visible light.

See Halas et al.

Structure sensitivity in heterogeneous catalysis is usually apparent from a strong dependence of the catalytic performance on the size of supported nanoparticles. Here, Hensen and co-workers introduce a form of structure sensitivity dependent on the size of the support. By tuning the size of the ceria–zirconia support, cobalt nanoparticles can be supported, achieving the optimum metal–support interaction. A facile oxygen transport is enabled at the corresponding interface, resulting in remarkable CO2 methanation activity.

See Parastaev et al.

Conventional gas diffusion electrodes improve transport of gaseous species, but they suffer from electrolyte penetration and flooding when used with non-aqueous solvents. Here, Manthiram and co-workers report a gas diffusion electrode architecture that is compatible with non-aqueous solvents to utilise sparingly soluble gases in electrochemical reactions. These electrodes are used to simultaneously reduce nitrogen and oxidise water-splitting-derived hydrogen to produce ammonia at ambient conditions.

See Lazouski et al.

Platinum nanoparticles are traditionally regarded as poor catalysts for the hydrochlorination of acetylene. Here, Pérez-Ramírez and co-workers demonstrate that by controlling the loading of this metal on a carbon support to obtain single-atom species, a superior catalyst can be obtained. Pt single atoms surpass the performance of their gold-based analogues and feature high stability, holding promise to replace industrial mercury-based catalysts and achieve a more sustainable production of vinyl chloride.

See Kaiser et al.

Biocatalysis is an enabling technology for a more sustainable future. This Insight provides an overview of engineering enzymes and microbes, as well as methods for interfacing them with abiological materials to improve their performance and range of applications.

The cover comes from an Article by Julia Sanz-Aparicio, Víctor Guallar, Manuel Ferrer and co-workers on engineering enzyme scaffolds with two active sites to synergistically combine biological and new-to-nature chemical transformations.

See Alonso et al.

Fujita, Abe, Miyauchi and co-workers report the use of ultraviolet light as the only energy source to promote dry reforming of methane and generate synthesis gas. The reaction is catalysed by rhodium particles supported on SrTiO3, where the support utilizes the photogenerated holes to oxidize methane and electrons channelled to the metal particles trigger the reduction of CO2. The process occurs at temperatures much lower than in the case of conventional thermal catalysis.

See Shoji, S. et al.

Willinger and co-workers report the in situ use of scanning electron microscopy as a surface-sensitive technique to study the dynamics of catalysed reactions, with the ability to image the effects of grain orientation dependent reactivity, spillover processes, and complex reaction–diffusion patterns. In the case of nitric oxide hydrogenation on polycrystalline platinum foil, such phenomena give rise to the formation of dissipative structures with intriguing spiral patterns.

See Barroo et al.