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Single‐atom heterogeneous catalysts (SACs) hold promise as sustainable alternatives to metal complexes in organic transformations. However, their working structure and dynamics remain poorly understood, hindering advances in their design. Exploiting the unique features of droplet‐based microfluidics, we present the first in‐situ assessment of a palladium SAC based on exfoliated carbon nitride in Suzuki–Miyaura cross‐coupling using X‐ray absorption spectroscopy. Our results confirm a surface‐catalyzed mechanism, revealing the distinct electronic structure of active Pd centers compared to homogeneous systems, and providing insights into the stabilizing role of ligands and bases. This study establishes a valuable framework for advancing mechanistic understanding of organic syntheses catalyzed by SACs. [ABSTRACT FROM AUTHOR]

Metal promotion could unlock high performance in zinc-zirconium catalysts, ZnZrOx, for CO2 hydrogenation to methanol. Still, with most efforts devoted to costly palladium, the optimal metal choice and necessary atomic-level architecture remain unclear. Herein, we investigate the promotion of ZnZrOx catalysts with small amounts (0.5 mol%) of diverse hydrogenation metals (Re, Co, Au, Ni, Rh, Ag, Ir, Ru, Pt, Pd, and Cu) prepared via a standardized flame spray pyrolysis approach. Cu emerges as the most effective promoter, doubling methanol productivity. Operando X-ray absorption, infrared, and electron paramagnetic resonance spectroscopic analyses and density functional theory simulations reveal that Cu0 species form Zn-rich low-nuclearity CuZn clusters on the ZrO2 surface during reaction, which correlates with the generation of oxygen vacancies in their vicinity. Mechanistic studies demonstrate that this catalytic ensemble promotes the rapid hydrogenation of intermediate formate into methanol while effectively suppressing CO production, showcasing the potential of low-nuclearity metal ensembles in CO2-based methanol synthesis.The ideal metal selection and atomic-level arrangement for catalysts in CO2 hydrogenation are still uncertain. Here, copper is identified as the most effective promoter for enhancing ZnZrOx catalysts when precisely structured into CuZn ensembles, offering new insights for designing superior catalysts for CO2-based methanol synthesis. [ABSTRACT FROM AUTHOR]

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Ternary Pd‐In2O3/ZrO2 catalysts exhibit technological potential for CO2‐based methanol synthesis, but developing scalable systems and comprehending complex dynamic behaviors of the active phase, promoter, and carrier are key for achieving high productivity. Here, we show that the structure of Pd‐In2O3/ZrO2 systems prepared by wet impregnation evolves under CO2 hydrogenation conditions into a selective and stable architecture, independent of the order of addition of Pd and In phases on the zirconia carrier. Detailed operando characterization and simulations reveal a rapid restructuring driven by the metal‐metal oxide interaction energetics. The proximity of InPdx alloy particles decorated by InOx layers in the resulting architecture prevents performance losses associated with Pd sintering. The findings highlight the crucial role of reaction‐induced restructuring in complex CO2 hydrogenation catalysts and offer insights into the optimal integration of acid‐base and redox functions for practical implementation. [ABSTRACT FROM AUTHOR]

Direct conversion of methane into value‐added chemicals, such as methanol under mild conditions, is a promising route for industrial applications. In this work, atomically dispersed Rh on TiO2 suspended in an aqueous solution was used for the oxidation of methane to methanol. Promoted by copper cations (as co‐catalyst) in solution, the catalysts exhibited high activity and selectivity for the production of methanol using molecular oxygen with the presence of carbon monoxide at 150 °C with a reaction pressure of 31 bar. Millimole level yields of methanol were reached with the selectivity higher than 99 % using the Rh/TiO2 catalysts with the promotion of the copper cation. CO was the reductive agent to generate H2 from H2O, which led to the formation of H2O2 through the reaction of H2 and O2. Atomically dispersed Rh activated the C−H bond in CH4 and catalyzed the oxidation using H2O2. Copper cations maintained the low‐valence state of Rh. Moreover, copper acted as a scavenger for suppressing the overoxidation, thus leading to the high selectivity of methanol. [ABSTRACT FROM AUTHOR]

Direct conversion of methane into value‐added chemicals, such as methanol under mild conditions, is a promising route for industrial applications. In this work, atomically dispersed Rh on TiO2 suspended in an aqueous solution was used for the oxidation of methane to methanol. Promoted by copper cations (as co‐catalyst) in solution, the catalysts exhibited high activity and selectivity for the production of methanol using molecular oxygen with the presence of carbon monoxide at 150 °C with a reaction pressure of 31 bar. Millimole level yields of methanol were reached with the selectivity higher than 99 % using the Rh/TiO2 catalysts with the promotion of the copper cation. CO was the reductive agent to generate H2 from H2O, which led to the formation of H2O2 through the reaction of H2 and O2. Atomically dispersed Rh activated the C−H bond in CH4 and catalyzed the oxidation using H2O2. Copper cations maintained the low‐valence state of Rh. Moreover, copper acted as a scavenger for suppressing the overoxidation, thus leading to the high selectivity of methanol. [ABSTRACT FROM AUTHOR]

The complexity of heterogeneous catalysts means that a priori design of new catalytic materials is difficult, but the well-defined nature of single-atom–alloy catalysts has made it feasible to perform unambiguous theoretical modeling and precise surface science experiments. Herein we report the theory-led discovery of a rhodium-copper (RhCu) single-atom–alloy catalyst for propane dehydrogenation to propene. Although Rh is not generally considered for alkane dehydrogenation, first-principles calculations revealed that Rh atoms disperse in Cu and exhibit low carbon-hydrogen bond activation barriers. Surface science experiments confirmed these predictions, and together these results informed the design of a highly active, selective, and coke-resistant RhCu nanoparticle catalyst that enables low-temperature nonoxidative propane dehydrogenation. [ABSTRACT FROM AUTHOR]

The article discusses the importance of developing improved in-situ characterization tools for designing heterogeneous catalysts for organic syntheses. The authors present an innovative in-situ X-ray absorption spectroscopy approach using droplet-based microfluidics to study palladium single-atom catalysts in Suzuki-Miyaura coupling. The results demonstrate the feasibility of the technique and its potential to provide new mechanistic insights. Additionally, another research article by different authors explores the discovery of non-Fenton-type reactive oxygen species driving abiotic CH4 production, offering a new approach for engineering CH4 production. [Extracted from the article]

The article titled "Titelbild: Droplet-Based Microfluidics Reveals Insights into Cross-Coupling Mechanisms over Single-Atom Heterogeneous Catalysts" discusses the development of in-situ characterization tools for heterogeneous catalysts in organic syntheses. The authors, Andrew J. deMello, Javier Pérez-Ramírez, Sharon Mitchell, and their colleagues, demonstrate the use of an innovative in-situ X-ray absorption spectroscopy approach using droplet-based microfluidics to study palladium single-atom catalysts in Suzuki-Miyaura coupling. The results of their study highlight the feasibility of this technique and its potential to provide new mechanistic insights. Additionally, the article mentions another research article by Shungui Zhou, Yujie Xiong, and their colleagues, which reports on the discovery of non-Fenton-type reactive oxygen species driving abiotic CH4 production, offering a new approach for engineering CH4 production. [Extracted from the article]

• Ni doping of Au NPs greatly enhances activity for MA-methanol oxidative coupling. • NiAu SAAs show 100% MMA selectivity, similar to bare Au. • [Au-O x ]- species are the active sites for methanol-methacrolein coupling. • The interaction of Ni atoms with gold promotes formation of the active [Au-O x ]- species. • High MMA yields on NiAu SAAs even at low methanol concentrations in the liquid phase. The oxidative cross-coupling of unsaturated aldehydes and alcohols with methanol is catalyzed by O-activated gold surfaces in both ambient pressure and UHV conditions. From liquid-phase studies it has been found that either the addition of a base or the use of a basic support is necessary for high yields of the corresponding methyl ester. Here we demonstrate that addition of a small amount of Ni, at the single atom limit, on supported Au nanoparticles, without the aid of a base in the reaction solution or the use of a basic support, is sufficient to activate Au for the selective oxidative esterification of methacrolein with methanol. The Ni concentration and dispersion are followed by ICP-AES and in situ DRIFTS, respectively. The active site appears to be the same for both NiAu and Au NPs; namely, an [Au-O x ]- species, as similar apparent activation energies of the reaction were found in kinetic studies over these two catalysts. Ni was also shown to allow for lower methanol concentrations to be used without affecting the catalytic activity and selectivity to the desired product, methyl methacrylate. In situ vibrational spectroscopy studies were conducted in an ATR-IR cell, where the reaction progress was monitored by detecting the gradual conversion of adsorbed reactants on the catalytic surface to intermediates and finally to the desired product, which was produced at close to 100% selectivity at conversions exceeding 25% at 60 ℃ on NiAu single atom alloy nanoparticles. [ABSTRACT FROM AUTHOR]

Keywords: CO2-Hydrierung; Metall-Metalloxid-Wechselwirkungen; Methanolsynthese; Operando Analyse; Pd-In2O3/ZrO2 Katalysator DE CO2-Hydrierung Metall-Metalloxid-Wechselwirkungen Methanolsynthese Operando Analyse Pd-In2O3/ZrO2 Katalysator 1 1 1 10/12/23 20231016 NES 231016 B Developing scalable systems b and understanding dynamic behaviors are crucial for advancing the technological potential of multicomponent catalysts for CO SB 2 sb -based methanol synthesis. In their Research Article (e202306563), Javier Pérez-Ramírez and co-workers show that the reaction-induced restructuring of Pd-In SB 2 sb O SB 3 sb /ZrO SB 2 sb systems, prepared via impregnation, leads to a unique architecture that integrates the necessary acid-base functionality of In SB 2 sb O SB 3 sb with the H SB 2 sb splitting ability of an InPd SB 2 sb alloy, while also ensuring high stability. [Extracted from the article]

Developing scalable systems and understanding dynamic behaviors are crucial for advancing the technological potential of multicomponent catalysts for CO2‐based methanol synthesis. In their Research Article (e202306563), Javier Pérez‐Ramírez and co‐workers show that the reaction‐induced restructuring of Pd‐In2O3/ZrO2 systems, prepared via impregnation, leads to a unique architecture that integrates the necessary acid‐base functionality of In2O3 with the H2 splitting ability of an InPd2 alloy, while also ensuring high stability. [ABSTRACT FROM AUTHOR]

Mining effluents can often contain heavy metals such as Lead (Pb), Zinc (Zn), Iron (Fe), Manganese (Mn), Cadmium (Cd), Arsenic (As) and if left untreated can cause damage to the local aquatic environment. In this study, it is demonstrated the operation of a 9 m³/h pilot unit (PU) installed in Greece. It consists of a pH regulation and oxidation stage, followed by filtration to a catalytic multimedia filter, activated carbon filter, and a reverse osmosis (RO) unit. PU is fed by the existing pretreatment installation outlet. Our results prove that PU installing improved the water quality of water discharge, so that the final concentrations of dissolved metals to be even lower than the legislation limits for potable water. The removal of Fe, Mn, and Zn was 90%–100%, Cd was 80%–90%, while Pb and As was <80%. Operational data demonstrated very good removal efficiency of the Filtration Stage so that RO stage can be omitted. PU successful application enables design to be applied covering the complete installation needs. The operation of PU is simple, automatic, and constant. It is environment-friendly and economically viable in terms of fixed and operational cost. [ABSTRACT FROM AUTHOR]

Direct conversion of methane into value‐added chemicals, such as methanol under mild conditions, is a promising route for industrial applications. In this work, atomically dispersed Rh on TiO2 suspended in an aqueous solution was used for the oxidation of methane to methanol. Promoted by copper cations (as co‐catalyst) in solution, the catalysts exhibited high activity and selectivity for the production of methanol using molecular oxygen with the presence of carbon monoxide at 150 °C with a reaction pressure of 31 bar. Millimole level yields of methanol were reached with the selectivity higher than 99 % using the Rh/TiO2 catalysts with the promotion of the copper cation. CO was the reductive agent to generate H2 from H2O, which led to the formation of H2O2 through the reaction of H2 and O2. Atomically dispersed Rh activated the C−H bond in CH4 and catalyzed the oxidation using H2O2. Copper cations maintained the low‐valence state of Rh. Moreover, copper acted as a scavenger for suppressing the overoxidation, thus leading to the high selectivity of methanol. [ABSTRACT FROM AUTHOR]

Direct conversion of methane into value‐added chemicals, such as methanol under mild conditions, is a promising route for industrial applications. In this work, atomically dispersed Rh on TiO2 suspended in an aqueous solution was used for the oxidation of methane to methanol. Promoted by copper cations (as co‐catalyst) in solution, the catalysts exhibited high activity and selectivity for the production of methanol using molecular oxygen with the presence of carbon monoxide at 150 °C with a reaction pressure of 31 bar. Millimole level yields of methanol were reached with the selectivity higher than 99 % using the Rh/TiO2 catalysts with the promotion of the copper cation. CO was the reductive agent to generate H2 from H2O, which led to the formation of H2O2 through the reaction of H2 and O2. Atomically dispersed Rh activated the C−H bond in CH4 and catalyzed the oxidation using H2O2. Copper cations maintained the low‐valence state of Rh. Moreover, copper acted as a scavenger for suppressing the overoxidation, thus leading to the high selectivity of methanol. [ABSTRACT FROM AUTHOR]

The article explores how high-loading single Platinum, Pt atom sites [Pt-O(OH)x] catalyze the CO preferential oxidation, PROX reaction with high activity and selectivity at mild conditions. It reports the synthesis of high-loading single Platinum atom catalysts with oxygen-bonded alkaline ions that stabilize the cationic Platinum.

The impact of ranolazine, an anti-ishemic agent with antiarrhythmic properties, on paroxysmal atrial fibrillation (PAF) in patients with coronary artery disease (CAD) remains unclear. Pacing devices can be useful tools for disclosing even asymptomatic PAF. Purpose of this study is to assess the effect of ranolazine on atrial fibrillation (AF), in patients with CAD, PAF and a dual-chamber pacemaker. We studied 74 patients with CAD, PAF, and sick sinus syndrome or atrio-ventricular block, treated with pacemakers capable to detect PAF episodes. The total time in AF, AF burden, and the number of PAF episodes within the last 6 months before enrolment in the study, mean AF duration per episode, and the QTc interval were initially assessed. Subsequently, patients were randomized into additional treatment with ranolazine (375 mg twice daily) or placebo. Following six months of treatment, all parameters were reassessed and compared to those before treatment. Ranolazine was associated with shorter total AF duration (81.56±45.24 hours versus 68.71±34.84 hours, p=0.002), decreased AF burden (1.89±1.05% versus 1.59±0.81%, p=0.002), and shortened mean AF duration (1.15±0.41 hours versus 0.92±0.35 hours, p=0.01). In the placebo group no such differences were observed. In both groups, no significant differences in the number of PAF episodes and QTc duration were observed. We conclude that in patients with CAD and PAF, ranolazine reduces the total time in AF, AF burden, and mean AF duration. These findings may imply additional antiarrhythmic properties of ranolazine on atrial myocardium and might indicate the necessity of its use in ischemic patients with PAF. [ABSTRACT FROM AUTHOR]

Using heterogeneous single-atom catalysts (SACs) in the Suzuki-Miyaura coupling (SMC) has promising economic and environmental benefits over traditionally applied palladium complexes. However, limited mechanistic understanding hinders progress in their design and implementation. Our study provides critical insights into the working principles of Pd 1 @C 3 N 4 , a promising SAC for the SMC. We demonstrate that the base, ligand, and solvent play pivotal roles in facilitating interface formation with reaction media, activating Pd centers, and modulating competing reaction pathways. Controlling the previously overlooked interplay between base strength, reagent solubility, and surface wetting is essential for mitigating mass transfer limitations in the triphasic reaction system and promoting catalyst reusability. Optimum conditions for Pd 1 @C 3 N 4 require polar solvents, intermediate base strength, and increased water content. Our investigations reveal that high selectivity requires minimizing competitive coordination of bases and phosphine ligands to the Pd centers, to avoid homocoupling and alternative reductive elimination mechanisms giving rise to phosphonium side-products. Furthermore, in situ XAS investigations probing electronic structures and coordination environments of Pd sites further rationalize the base and ligand coordination, confirming and expanding upon previous computational hypotheses for Pd 1 @C 3 N 4 . This understanding allows for designing a more selective ligand-free reaction pathway using the solvent and base to modulate the chemical environment of the active sites. We highlight the importance of environment-compatible surface tension, the creation of coordinatively available active sites, and the stabilization of partially reduced Pd centers, emphasizing the importance of mechanistic studies to advance the design of SACs in organic liquid phase reactions., Competing Interests: The authors declare no competing financial interest., (© 2024 The Authors. Published by American Chemical Society.)

Ternary Pd-In 2 O 3 /ZrO 2 catalysts exhibit technological potential for CO 2 -based methanol synthesis, but developing scalable systems and comprehending complex dynamic behaviors of the active phase, promoter, and carrier are key for achieving high productivity. Here, we show that the structure of Pd-In 2 O 3 /ZrO 2 systems prepared by wet impregnation evolves under CO 2 hydrogenation conditions into a selective and stable architecture, independent of the order of addition of Pd and In phases on the zirconia carrier. Detailed operando characterization and simulations reveal a rapid restructuring driven by the metal-metal oxide interaction energetics. The proximity of InPd x alloy particles decorated by InO x layers in the resulting architecture prevents performance losses associated with Pd sintering. The findings highlight the crucial role of reaction-induced restructuring in complex CO 2 hydrogenation catalysts and offer insights into the optimal integration of acid-base and redox functions for practical implementation., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Copper catalysts are attractive candidates for Hg-free vinyl chloride monomer (VCM) production via acetylene hydrochlorination due to their non-toxic nature and high stability. However, the optimal architecture for Cu-based catalysts at the nanoscale is not yet fully understood. To address this gap, the metal precursor and the annealing temperature are modified to prepare copper nanoparticles or single atoms, either in chlorinated or ligand-free form, on an unmodified carbon support. Evaluation in the reaction reveals a remarkable convergence of the performance of all materials to the stable VCM productivity of the single-atom catalyst. In-depth characterization by advanced microscopy, quasi in situ and operando spectroscopy, and simulations uncover a reaction-induced formation of low-valent, single atom Cu(I)Cl site motif, regardless of the initial nanostructure. Various surface oxygen groups promote nanoparticle redispersion by stabilizing single-atom CuCl x species. The anchoring site structure does not strongly influence the acetylene adsorption energy or the crucial role they play in stabilizing key reaction intermediates. A life-cycle assessment demonstrates the potential environmental benefits of copper catalysts over state-of-the-art alternatives. This work contributes to a better understanding of optimal metal speciation and highlights the sustainability of Cu-based catalysts for VCM production., (© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

Direct conversion of methane into value-added chemicals, such as methanol under mild conditions, is a promising route for industrial applications. In this work, atomically dispersed Rh on TiO 2 suspended in an aqueous solution was used for the oxidation of methane to methanol. Promoted by copper cations (as co-catalyst) in solution, the catalysts exhibited high activity and selectivity for the production of methanol using molecular oxygen with the presence of carbon monoxide at 150 °C with a reaction pressure of 31 bar. Millimole level yields of methanol were reached with the selectivity higher than 99 % using the Rh/TiO 2 catalysts with the promotion of the copper cation. CO was the reductive agent to generate H 2 from H 2 O, which led to the formation of H 2 O 2 through the reaction of H 2 and O 2 . Atomically dispersed Rh activated the C-H bond in CH 4 and catalyzed the oxidation using H 2 O 2 . Copper cations maintained the low-valence state of Rh. Moreover, copper acted as a scavenger for suppressing the overoxidation, thus leading to the high selectivity of methanol., (© 2022 Wiley-VCH GmbH.)

The preferential oxidation of CO (PROX) in hydrogen-rich fuel gas streams is an attractive option to remove CO while effectively conserving energy and H 2 . However, high CO conversion with concomitant high selectivity to CO 2 but not H 2 O is challenging. Here, we report the synthesis of high-loading single Pt atom (2.0 weight %) catalysts with oxygen-bonded alkaline ions that stabilize the cationic Pt. The synthesis is performed in aqueous solution and achieves high Pt atom loadings in a single-step incipient wetness impregnation of alumina or silica. Promisingly, these catalysts have high CO PROX selectivity even at high CO conversion (~99.8% conversion, 70% selectivity at 110°C) and good stability under reaction conditions. These findings pave the way for the design of highly efficient single-atom catalysts, elucidate the role of ─OH species in CO oxidation, and confirm the absence of a support effect for our case., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).)

The impact of ranolazine, an anti-ishemic agent with antiarrhythmic properties, on paroxysmal atrial fibrillation (PAF) in patients with coronary artery disease (CAD) remains unclear. Pacing devices can be useful tools for disclosing even asymptomatic PAF. Purpose of this study is to assess the effect of ranolazine on atrial fibrillation (AF), in patients with CAD, PAF and a dual-chamber pacemaker. We studied 74 patients with CAD, PAF, and sick sinus syndrome or atrio-ventricular block, treated with pacemakers capable to detect PAF episodes. The total time in AF, AF burden, and the number of PAF episodes within the last 6 months before enrolment in the study, mean AF duration per episode, and the QTc interval were initially assessed. Subsequently, patients were randomized into additional treatment with ranolazine (375 mg twice daily) or placebo. Following six months of treatment, all parameters were reassessed and compared to those before treatment. Ranolazine was associated with shorter total AF duration (81.56±45.24 hours versus 68.71±34.84 hours, p=0.002), decreased AF burden (1.89±1.05% versus 1.59±0.81%, p=0.002), and shortened mean AF duration (1.15±0.41 hours versus 0.92±0.35 hours, p=0.01). In the placebo group no such differences were observed. In both groups, no significant differences in the number of PAF episodes and QTc duration were observed. We conclude that in patients with CAD and PAF, ranolazine reduces the total time in AF, AF burden, and mean AF duration. These findings may imply additional antiarrhythmic properties of ranolazine on atrial myocardium and might indicate the necessity of its use in ischemic patients with PAF.