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Bimetallic single–atom catalysts (b–SACs) have recently gained prominence by virtue of the unique catalytic cooperative interactions they can exhibit, intertwining electronic and geometric effects. To date, research efforts have exclusively focused on direct mechanisms such as electron density transfer or sequential reactivity. Herein, the first study on indirect, coordination–induced catalytic synergies in carbon‐supported RuPt SACs is conducted. To this end, a holistic approach is developed, combining i) precision synthesis, ii) advanced characterization, iii) exploration of single–site adsorption properties via the hydrogen evolution reaction, and iv) modeling through density functional theory. Despite the lack of both intermetallic coordination in the first or second shell and charge redistribution effects, the RuPt SACs exhibit a H2 formation rate enhanced up to 15–fold compared with their monometallic counterparts. To unfold the origin of the intermetallic cooperativity, modifications of the structural and catalytic properties induced by the integration of a second metal species are investigated. Thus, Pt atoms are found to selectively occupy the most energeticallyfavorable cavities in the support, prompting Ru atoms to assume a distinct, more active, configuration. This contribution unveils a novel principle of bimetallic cooperativity, demonstrating the key role of integrative experimental and computational analyses in studying b–SACs. [ABSTRACT FROM AUTHOR]

Nanostructuring earth‐abundant metals as single atoms or clusters of controlled size on suitable carriers opens new routes to develop high‐performing heterogeneous catalysts, but resolving speciation trends remains challenging. Here, we investigate the potential of low‐nuclearity iron catalysts in the continuous liquid‐phase semi‐hydrogenation of various alkynes. The activity depends on multiple factors, including the nuclearity and ligand sphere of the metal precursor and their evolution upon interaction with the mesoporous graphitic carbon nitride scaffold. Density functional theory predicts the favorable adsorption of the metal precursors on the scaffold without altering the nuclearity and preserving some ligands. Contrary to previous observations for palladium catalysts, single atoms of iron exhibit higher activity than larger clusters. Atomistic simulations suggest a central role of residual carbonyl species in permitting low‐energy paths over these isolated metal centers. [ABSTRACT FROM AUTHOR]

In article number 1605785, Javier Pérez‐Ramírez and co‐workers investigate the synthesis of single‐atom heterogeneous catalysts based on precious metals and using graphitic carbon nitride as the carrier. Advanced characterization and simulations reveal the impact of the carrier properties, and of the metal identity and method of introduction on the speciation. Controlling the metal‐carrier interaction and exposing the reactive metal centers are key for maximizing the potential of these materials. [ABSTRACT FROM AUTHOR]

The catalytic oxidation of hydrogen chloride to chlorine (Deacon reaction) is an attractive means to recover Cl2 from HCl-containing waste streams in the chemical industry. Recently, RuO2 supported on TiO2 rutile has been industrially implemented for large-scale chlorine manufacture. However, detailed understanding of the reaction mechanism over claimed catalysts has not been acquired. Our tests in a fixed-bed reactor at ambient pressure concluded that RuO2 powder is highly active for Cl2 production. Characterization of the fresh and used RuO2 samples by ex situ XRD and XPS revealed no appreciable alteration of the bulk structure and limited chlorination of the catalyst. Ab initio thermodynamics predicted that the initial state of the RuO2(110) surface is partially over-oxidized, while the surface after reaction contains both oxygen and chlorine. DFT described the Deacon reaction with a Mars–van Krevelen type mechanism consisting of five steps: hydrogen abstraction from HCl, recombination of atomic chlorine, hydroxyl recombination, water desorption, and dissociative oxygen adsorption. An increased chlorine production was observed experimentally when increasing the feed O2-to-HCl ratio. This can be ascribed both to the lower recombination energy of chlorine atoms to gas-phase Cl2 at high coverages and the faster surface reoxidation due to higher partial oxygen pressures. [Copyright &y& Elsevier]