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Two new supramolecular photocatalysts made of covalently linked Ru(II) polypyridine chromophore subunits ([Ru(bpy)3]2+-type species; bpy = 2,2′-bipyridine) and [RuL(pic)2] (L = 2,2′-bipyridine-6,6′-dicarboxylic acid; pic = 4-picoline) water oxidation catalyst subunits have been prepared. The new species, 1 and 2, contain chromophore and catalyst subunits in the molecular ratios 1:1 and 1:2, respectively. The model chromophore species [Ru(bpy)2(L1)]2+ (RuP1; L1=4-[2-(4-pyridyl)-2-hydroxyethyl]-4-methyl-2,2′-bipyridine) and [Ru(bpy)2(L2)]2+ (RuP2; L2 = 4,4′-bis[2-(4-pyridyl)-2-hydroxyethyl]-2,2′-bipyridine) have also been prepared. The absorption spectra, oxidation behavior, and luminescent properties of 1 and 2 have been studied, and the results indicate that each subunit largely maintains its own properties in the supramolecular species. However, the luminescence of the chromophore subunits is significantly quenched in 1 and 2 in comparison with the luminescence of the respective model species. Both 1 and 2 exhibit catalytic water oxidation in the presence of cerium ammonium nitrate, exhibiting an I2M mechanism, with a better efficiency than the known catalyst [RuL(pic)2] under the same experimental conditions. Upon light irradiation, in the presence of persulfate as a sacrificial acceptor agent, 1 and 2 are more efficient photocatalysts than a system made of separated [Ru(bpy)3]2+ and [RuL(pic)2] species, highlighting the advantage of using multicomponent, supramolecular species with respect to isolated species. The O–O bond formation step is I2M, even in the photo-driven process. The photocatalytic process of 2 is more efficient than that of 1, with the turnover frequency reaching a value of 1.2 s−1. A possible reason could be an increased local concentration of catalytic subunits in the needed bimolecular assembly required for the I2M mechanism in 2 with respect to 1, a consequence of the presence of two catalytic subunits in each multicomponent species 2. [ABSTRACT FROM AUTHOR]

This study proposes a novel one‐pot method to produce 2,5‐furandicarboxylic acid (FDCA), which effectively simplifies the preparation process of FDCA by directly utilizing the biomass raw material corncob and its derived carbon‐based catalysts. In this work, we first prepared two different carbon‐based catalysts from corncobs: a ruthenium‐supported catalyst (Ru/C) and a sulfonated carbon catalyst. After detailed characterization and performance testing, these two catalysts were used to catalyze the pretreated corncob mixture to produce FDCA. Under optimized conditions, even using 0.12 g of Ru/C catalyst at a microwave power of 200 W, the yield of FDCA can reach 27 mol%. In comparison, the FDCA yield of the sulfonated carbon catalyst under the same conditions was 19 mol%. This work not only demonstrates the possibility of efficient production of FDCA by utilizing biomass resources and a simplified chemical conversion process, but also highlights the importance of selecting appropriate catalysts and controlling reaction conditions in improving yields. Through this method, we can promote the development of biomass conversion technology in a more efficient and environmentally friendly direction, providing technical support for the commercial production of bio‐based chemicals. [ABSTRACT FROM AUTHOR]

Multicomponent catalysts can be designed to synergistically combine reaction intermediates at interfacial active sites, but restructuring makes systematic control and understanding of such dynamics challenging. We here unveil how reducibility and mobility of indium oxide species in Ru‐based catalysts crucially control the direct, selective conversion of CO2 to ethanol. When uncontrolled, reduced indium oxide species occupy the Ru surface, leading to deactivation. With the addition of steam as a mild oxidant and using porous polymer layers to control In mobility, Ru−In2O3 interface sites are stabilized, and ethanol can be produced with superior overall selectivity (70 %, rest CO). Our work highlights how engineering of bifunctional active ensembles enables cooperativity and synergy at tailored interfaces, which unlocks unprecedented performance in heterogeneous catalysts. [ABSTRACT FROM AUTHOR]

The activity profile of the new indenylidene complexes containing two unsymmetrical N‐heterocyclic carbene (NHC) ligands was investigated. They turned out to be effective in both straightforward olefin metathesis reactions, such as ring‐closing metathesis (RCM) of diethyl diallylmalonate, as well as in more demanding processes, such as RCM of 2,2‐di‐(2‐methylallyl)tosylate leading to a product bearing a tetrasubstituted double bond, and in selective ethenolysis of methyl and ethyl oleate. [ABSTRACT FROM AUTHOR]

Investigating clean and sustainable hydrogen generation from water splitting requires cost‐effective and highly efficient electrocatalysts for the hydrogen evolution reaction (HER). Ruthenium (Ru)‐based heterostructure catalysts have emerged as promising alternatives to precious Pt, offering significant potential to overcome current bottlenecks. Recent advancements in Ru‐based heterostructure catalysts have focused on achieving a balance between catalytic activity and stability. An overview of these developments provides insights into catalytic mechanisms and facilitates the development of novel catalysts. This review begins with an exploration of the enhanced activity of heterostructure catalysts, followed by a critical summary of synthetic strategies employed to fabricate these catalysts and their catalytic performances for HER. Attention is then directed to experimental endeavors aimed at enhancing the HER performance of Ru‐based heterostructure catalysts. Finally, the opportunities and challenges in developing heterostructure catalysts from the perspectives of material design and synthesis are discussed. Through these discussions, a comprehensive understanding of Ru‐based heterostructure catalysts and inspiring future research directions is the aim to provide. [ABSTRACT FROM AUTHOR]

A series of M/NiCo-Ferrite (M: Pt, Pd, Ru, and Rh) nanoparticles were successfully synthesized, through a facile sol–gel auto-combustion followed by impregnation-reduction approach, as a catalyst for hydrogen generation from hydrolysis of NaBH4. All synthesized samples were characterized by XRD, N2 adsorption–desorption method, ICP-OES, FE-SEM, and EDX analysis. Compared to the other samples, it was observed that the Rh/NiCo-Ferrite sample exhibited higher particle distribution and surface area. To evaluate the hydrogen generation rate, the hydrolysis was carried out at a temperature of 35 °C, with an aqueous solution containing 5 wt.% NaBH4 and 3 wt.% NaOH. The experimental findings indicate that the Rh/NiCo-Ferrite sample exhibited a superior rate of hydrogen generation, with an average value of 11,667 mL/min.gcat, compared to the other samples studied. Enhanced catalytic properties may be responsible for its high activity. In addition, the activation energy of hydrolysis of sodium borohydride over the Rh/NiCo-Ferrite sample was 54.5 kJ/mol which is lower than the activation energy of many Ferrite-based catalysts. Moreover, the re-usability test of the Rh/NiCo-Ferrite sample denoted a decline in the catalytic activity after 4 recycling experiments due to the alterations in morphology and the reduction in the quantity of active phase. [ABSTRACT FROM AUTHOR]

The performance of a set of bimetallic Ru-Co catalysts dispersed on the TiO2 anatase phase, synthesized by the co-deposition–precipitation with urea method, was tested in the CO2 production by the entire oxidation of C3H8. The presence of properly dispersed ruthenium nanoparticles on a Co/TiO2-anatase support was notably favorable for enhancing the C3H8 activity/selectivity. Likewise, an increase in the combined acidity (Brönsted and Lewis) was also observed, and the interaction between Ru0-CoOx species stabilized on TiO2 prompted the C3H8 oxidation at low temperature. The performance of bimetallic Ru-Co/TiO2 catalysts was enhanced by increasing Ru0 species and loading, showing more efficient C3H8 oxidation by the combination of Ru0-CoOx, as revealed by DRIFTS, XPS, H2-TPR, and HAADF-STEM characterization outcomes. The higher acidity of the catalysts containing Ru (1.5 wt%) and Co (3 wt%) as well as the reducibility enhancement of the Ru and Co species led to the best capacity of these catalysts for C3H8 oxidation to CO2 under the experimental conditions employed in this study. [ABSTRACT FROM AUTHOR]

A novel phosphine‐free ruthenium pincer complex based on an NNN pincer ligand has been prepared and fully characterized. The complex was subsequently employed as an efficient catalyst for the N‐methylation of amines and the direct N‐methylation of nitroarenes using methanol as a C1 source under mild reaction conditions following the borrowing‐hydrogen approach. Both of the catalytic transformations were performed with only catalytic amounts of base under closed air conditions without using any other additives. [ABSTRACT FROM AUTHOR]

As a dual-functional catalyst for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), Ru clusters have great potential, but there are certain difficulties regarding their stability on the substrate and the tunability of their electronic environment. Here, the S doped graphited biochar aerogel electrocatalyst was designed and synthesized using terrestrial lignin and algal polysaccharide as a carbon substrate. The Ru clusters were anchored on the S-doped carbon aerogel (P-Ru/SC) by carefully designing the Ru-S bond via a novel plasma assisted high temperature carbonization treatment. The optimized P-Ru/SC-2 catalyst exhibits excellent electrocatalytic performance for the HER and OER, achieving ultra-small overpotentials of 119.6 mV and 193.4 mV at 10 mA cm-2. The dual-electrode requires only 1.47 V to reach 10 mA cm-2. It is worth noting that a large number of S sites on graphited carbon can strongly interact with the Ru clusters, significantly improving the catalytic activity and stability for the HER and OER. [ABSTRACT FROM AUTHOR]

Employing catalytic decomposition to break down reducing agents in intermediate-level radioactive waste during nuclear fuel reprocessing offers significant advantages. This study focuses on investigating the deactivation behavior of 5% Ru/C catalysts by two different synthesis processes used for reducing agent destruction. Deactivation experiments were conducted by subjecting the 5% Ru/C catalysts to 100 and 150 reaction cycles. Changes in the concentration of free radicals on the carbon-based carrier were measured to analyze the loading position and loss of Ru ions. Additionally, sorption–desorption curves and pore size distributions of the four catalysts were obtained. Analysis results reveal that Ru ions on the catalyst adsorb onto active free radical sites on the carbon-based carrier. Under ultrasonic conditions, some Ru ions partially desorb from the free radical sites on the carbon-based carrier, and desorbed Ru ions may adsorb onto weak free radical sites, while undesorbed Ru ions may adsorb onto strong free radical sites. After hundreds of hours of reaction, SM1 and SM2 exhibited approximately a 30% decrease in specific surface area and pore volume compared to SM0. However, the catalyst activity remained unchanged, and the catalyst pore size remained essentially unchanged, which primarily means that the micropores on the catalyst's surface have undergone corrosion and damage. [ABSTRACT FROM AUTHOR]

This study prepared a series of cerium oxide-based catalysts with different metal ruthenium loadings using an initial wet impregnation method. The results demonstrate that the prepared 1.4Ru/CeO 2 catalyst exhibits outstanding catalytic performance and activity stability. Under the condition where the Ru loading is only 1.4 wt%, the catalyst achieves almost complete NH 3 conversion at 500 °C, with a hydrogen production rate of 16.59 mmol gcat−1 min−1. Furthermore, after a 48-h long-term test, the activity remains stable. Characterization tests show that the metal ruthenium is uniformly distributed on the surface of cerium dioxide, with particle sizes ranging from 3 to 6 nm. Notably, a structure characterized by lattice stripes overlapping between the metal and support is observed. Increasing the Ru loading can enhance the surface acidity sites of the catalyst and the interaction between the metal and the support, which plays a crucial role in the long-term stability of the catalyst. Additionally, the abundant oxygen vacancies in cerium dioxide and its low cerium oxidation-reduction potential facilitate electron transfer to ruthenium, enhancing the adsorption of NH 3 and accelerating the desorption of N 2. [Display omitted] • The catalytic performance is related to the dispersion of the metal and the oxygen vacancies on the surface of the support. [ABSTRACT FROM AUTHOR]

In recent years, single‐atom catalysts (SACs) have become the most active part of the catalytic field due to their excellent catalytic activity. Among them, Ru SACs exhibit excellent performance in many catalytic applications due to their high atomic utilization efficiency, catalytic activity and selectivity, and relatively low cost. In order to understand the structure–performance relationship and potential catalytic mechanism of Ru SACs, this review summarizes the research progress of Ru SACs in the fields of electrocatalytic water splitting, fuel cells, nitrogen reduction, and nitrate reduction in recent years. The catalytic process of Ru single atom in different synthesis methods and modification strategies is summarized. Finally, some opportunities and challenges for the future development of Ru SACs are prospected. [ABSTRACT FROM AUTHOR]

The 5 wt% Ru/AC catalysts were prepared using the impregnation method. The catalysts were characterized by N2 physical adsorption, XRD, SEM, EDX, TEM and ICP-AES. The catalytic activity and stability of the catalysts in decomposing hydroxylamine nitrate (HAN) and hydrazine nitrate (HN) in nitric acid were evaluated. The results demonstrated that the Ru/AC catalyst effectively decomposed HAN and HN with complete conversion under moderate reaction conditions (60–90 °C). When used for an extended duration of 1580 hours in radioactive nitric acid waste liquid, this catalyst displayed a remarkable processing capacity of 6.32 kilograms per gram of catalyst. Due to its environmentally friendly nature resulting from harmless gas product formation along with its simple device structure design, this protocol offers practicality and economic attractiveness. [ABSTRACT FROM AUTHOR]

The electrocatalytic nitrogen reduction reaction (NRR) for synthesizing ammonia holds promise as an alternative to the traditional high-energy-consuming Haber–Bosch method. Rational and accurate catalyst design is needed to overcome the challenge of activating N2 and to suppress the competitive hydrogen evolution reaction (HER). Single-atom catalysts have garnered widespread attention due to their 100% atom utilization efficiency and unique catalytic performance. In this context, we constructed theoretical models of metal single-atom catalysts supported on titanate nanosheets (M-TiNS). Initially, density functional theory (DFT) was employed to screen 12 single-atom catalysts for NRR- and HER-related barriers, leading to the identification of the theoretically optimal NRR catalyst, Ru-TiNS. Subsequently, experimental synthesis of the Ru-TiNS single-atom catalyst was successfully achieved, exhibiting excellent performance in catalyzing NRR, with the highest NH3 yield rate reaching 15.19 μmol mgcat−1 h−1 and a Faradaic efficiency (FE) of 15.3%. The combination of experimental results and theoretical calculations demonstrated the efficient catalytic ability of Ru sites, validating the effectiveness of the constructed theoretical screening process and providing a theoretical foundation for the design of efficient NRR catalysts. [ABSTRACT FROM AUTHOR]

A potassium (K)-promoted Ru-based siliceous molecular sieve catalyst, K-nRu-MCM-41, was successfully synthesized via a hydrothermal method. The combined analysis of XRD, FT-IR and XPS data revealed that Ru exists in the framework of the molecular sieves as RuO2 species, leading to structural alterations. SEM and TEM images demonstrated that Ru doping disrupts the morphology of the molecular sieves, while K addition effectively preserves the original morphology and further enhances particle dispersion. The ammonia decomposition performance test indicated that K promotes the activity of the molecular sieve catalysts. At 450 °C and 12 000 mL gcat−1 h−1, K-4Ru-MCM-41 achieved 82.7% ammonia conversion and 253.6 mmol gRu−1 min−1 hydrogen production, respectively, which was a 7.6% increase in ammonia conversion compared with 4Ru-MCM-41. Furthermore, the K-4Ru-MCM-41 catalyst exhibited excellent reusability, maintaining its stable catalytic activity performance after 30 h. [ABSTRACT FROM AUTHOR]

γ‐Valerolactone (GVL) can be obtained by efficient hydrogenation of levulinic acid using ruthenium‐based catalysts in an aqueous medium. This paper reports an in‐depth study on the activity and selectivity of Ru catalysts supported on zirconia‐alumina, focusing on the effect of Ru concentration (0.5, 1.5 and 3 wt. % of Ru) and the selection of operational reaction variables. The results showed that the activity strongly depends on the number and oxidation state of the supported ruthenium particles. The most active catalyst, Ru3/ZA, presented the highest number of nanometric particles of zerovalent Ru and the highest number of acid sites. This catalyst gave ca. 100 % selectivity towards GVL, at high conversion of levulinic acid (over 99 %) under the best operating conditions evaluated (120 °C, 3 MPa H2 pressure, 1 h of reaction, and 0.1 g of catalyst). In addition, this catalyst kept high levels of conversion and selectivity after successive reuse cycles. [ABSTRACT FROM AUTHOR]

CO and H 2 S poisoning of Pt-based catalysts for hydrogen oxidation reaction (HOR) stands as one of the long-standing hindrances to the widespread commercialization of proton exchange membrane fuel cells. In this paper, a Ru/Ti 4 O 7 catalyst is successfully synthesized by the microwave-thermal method. This Ru/Ti 4 O 7 catalyst shows a much higher noble metal mass activity than those of commercial PtRu/C and conventional Ru/C catalysts. The performance of the Ru/Ti 4 O 7 catalyst under the exist of CO or H 2 S shows insignificant current decay, which is far superior to commercial PtRu/C and Pt/C catalysts. In this Ru/Ti 4 O 7 catalyst, the electron transfer between Ru and Ti to form d-p orbital hybridization is considered to be responsible for the favorable catalytic HOR performance and the corresponding CO and H 2 S tolerance. The interaction mechanism formed by electron transfer may open a promising way for the subsequent development of anti-poisoning catalysts for PEM fuel cell hydrogen oxidation reaction. [Display omitted] • Ru/Ti 4 O 7 catalyst shows a superior noble metal mass activity than those of commercial Pt–Ru/C based catalysts. • Ru/Ti 4 O 7 catalyst exhibits excellent resistance to CO poisoning. • The catalyst is extremely resistant to H 2 S while remaining CO-tolerant. • MSI of Ru/Ti 4 O 7 ensures catalytic activity and anti-poisoning properties. [ABSTRACT FROM AUTHOR]

Robert H Grubbs (1942–2021), Nobel laureate and former professor of Caltech, USA, is celebrated for his path breaking discovery of a series of ruthenium carbene based organometallic catalysts, well known as Grubbs catalysts. These catalysts are widely used by chemists across the world for carrying out a variety of olefin metathesis reactions under mild and ambient conditions. The article describes the synthesis and development of Grubbs ruthenium carbene catalysts and their closely related analogues. Their differences in structure, reactions and properties, their advantages and disadvantages when applied as catalysts in olefin metathesis reactions are briefly highlighted. [ABSTRACT FROM AUTHOR]

Ru(II)‐catalyzed and solvent‐switched [3+2]‐spiroannulation and [4+n] (n=1, 2, 3) annulations of 2‐aryl quinazolinone or 2‐aryl‐2,3‐dihydrophthalazine‐1,4‐diones with ynones or alkynyl alcohol or 1,3‐diynes under mild reaction conditions have been analyzed. These reactions take place in the presence of the appropriate solvent and features a redox‐neutral pathway. Ynone serves as an 'atypical one‐carbon unit' in [4+1] annulation and generates a tetrasubstituted carbon center bearing diverse heterocycles through [3+2] and [4+1] annulation strategies. Post transformations of the synthesized spiro‐products augments the potential of the developed methodology. [ABSTRACT FROM AUTHOR]

Singlet oxygen (1O2) is an exceptional reactive oxygen species in advanced oxidation processes for environmental remediation. Despite single‐atom catalysts (SACs) representing the promising candidate for the selective generation of 1O2 from peroxymonosulfate (PMS), the necessity to meticulously regulate the coordination environment of metal centers poses a significant challenge in the precisely‐controlled synthetic method. Another dilemma to SACs is their high surface free energy, which results in an inherent tendency for the surface migration and aggregation of metal atoms. We here for the first time reported that Ru nanoparticles (NPs) synthesized by the facile pyrolysis method behave as robust Fenton‐like catalysts, outperforming Ru SACs, towards efficient activation of PMS to produce 1O2 with nearly 100 % selectivity, remarkably improving the degradation efficiency for target pollutants. Density functional theory calculations have unveiled that the boosted PMS activation can be attributed to two aspects: (i) enhanced adsorption of PMS molecules onto Ru NPs, and (ii) decreased energy barriers by offering adjacent sites for promoted dimerization of *O intermediates into adsorbed 1O2. This study deepens the current understanding of PMS chemistry, and sheds light on the design and optimization of Fenton‐like catalysts. [ABSTRACT FROM AUTHOR]

Solid oxide fuel cells (SOFCs) are considered the most efficient technology for the direct conversion of hydrocarbons to electrical energy. Although the commonly used Ni/YSZ cermet materials in SOFCs show excellent electrocatalytic properties in H 2 fuel, they suffer from carbon deposition problem when hydrocarbon fuels are used. In this work, we study the use of Ni 0 · 05 Ru 0.05 -Mo 2 C with a porous nanorod-shaped morphology as an internal reforming catalyst layer for methane-fueled SOFCs to solve the degradation of cell performance due to carbon deposition. The electrochemical performance and coking tolerance of two types of cells with and without the catalyst layer were systematically studied using methane and hydrogen as fuels. With the catalyst layer, the single cell using methane as fuel exhibits an improvement in peak power density by 24%, increasing from 297 to 367 mW cm−2 and there was no diffusion barrier for fuel gases within the cell. Furthermore, the cell can stably run for 100 h in methane at 700 °C. The improvement of electrochemical performance is attributed to the synergistic effect of Ni and Ru sites anchored on the porous Mo 2 C nanorods catalyst based on strong metal-support interactions, promoting the effective catalytic conversion of CH 4 to CO and H 2. This study demonstrates that the integration of a catalyst layer for internal reforming is an effective strategy for the direct use of methane in SOFCs. • Porous Mo 2 C nanorods loaded with Ni and Ru bimetal nanoparticles were prepared. • The NiRu–Mo 2 C nanorods were used as an internal reforming catalyst layer for SOFCs. • The NiRu–Mo 2 C nanorod catalyst layer improves the cell performance in CH 4. • The cell with the catalyst layer shows excellent long-term stability. [ABSTRACT FROM AUTHOR]

The availability of catalytic sites for contact with reactants is a key issue to improve the performance of a catalyst, where constructing hollow structured nanomaterials has been considered as an effective strategy. Here, an N-doped carbon supported Ru catalyst with an interior cavity was synthesized by etching a MOF-derived core–shell precursor, in which metal Ru can be highly dispersed in the porous shell. This catalyst shows 98.7% conversion and >99% selectivity towards p-chloroaniline in the hydrogenation of p-chloronitrobenzene, which is better than the corresponding supported catalyst. Moreover, it also displays excellent stability with 5 cycle runs and good substrate universality for the hydrogenation of extensive substituted nitroarenes. Various characterization techniques and control experiments reveal the advantage of the unique structure to promote the mass transport and adsorption of reactant molecules on Ru sites. This work provides a novel strategy to design an efficient Ru-based catalyst for chemoselective hydrogenation. [ABSTRACT FROM AUTHOR]

The development of direct dimethyl ether (DME) solid oxide fuel cells (SOFCs) has several drawbacks, due to the low catalytic activity and carbon deposition of conventional Ni–zirconia-based anodes. In the present study, the insertion of 2.0 wt.% Ru-Ce0.7Zr0.3O2−δ (ruthenium–zirconium-doped ceria, Ru-CZO) as an anode catalyst layer (ACL) is proposed to be a promising solution. For this purpose, the CZO powder was prepared by the sol–gel synthesis method, and subsequently, nanoparticles of Ru (1.0–2.0 wt.%) were synthesized by the impregnation method and calcination. The catalyst powder was characterized by BET-specific surface area, X-ray diffraction (XRD), field emission scanning electron microscopy with an energy-dispersive spectroscopy detector (FESEM-EDS), and transmission electron microscopy (TEM) techniques. Afterward, the catalytic activity of Ru-CZO catalyst was studied using DME partial oxidation. Finally, button anode-supported SOFCs with Ru-CZO ACL were prepared, depositing Ru-CZO onto the anode support and using an annealing process. The effect of ACL on the electrochemical performance of cells was investigated under a DME and air mixture at 750 °C. The results showed a high dispersion of Ru in the CZO solid solution, which provided a complete DME conversion and high yields of H2 and CO at 750 °C. As a result, 2.0 wt.% Ru-CZO ACL enhanced the cell performance by more than 20% at 750 °C. The post-test analysis of cells with ACL proved a remarkable resistance of Ru-CZO ACL to carbon deposition compared to the reference cell, evidencing the potential application of Ru-CZO as a catalyst as well as an ACL for direct DME SOFCs. [ABSTRACT FROM AUTHOR]

Colloidal Ru nanoparticles (NP) display interesting catalytic properties for the hydrogenation of (hetero)arenes as they proceed efficiently in mild reaction conditions. In this work, a series of Ru based materials was used in order to selectively hydrogenate quinaldine and assess the impact of the stabilizing agent on their catalytic performances. Ru nanoparticles stabilized with polyvinylpyrrolidone (PVP) and 1‐adamantanecarboxylic acid (AdCOOH) allowed to obtain 5,6,7,8‐tetrahydroquinaldine with a remarkable selectivity in mild reaction conditions by choosing the suitable solvent. The presence of a carboxylate ligand on the surface of the Ru NP led to an increase in the activity when compared to Ru/PVP catalyst. The stabilizing agent had also an impact on the selectivity, as carboxylate ligand modified catalysts promoted the selectivity towards 1,2,3,4‐tetrahydroquinaldine, with bulky carboxylate displaying the highest ones. [ABSTRACT FROM AUTHOR]

On-site hydrogen generation from ammonia decomposition is a promising technology to address the challenges of direct transportation and storage of hydrogen. The main problems with the existing support materials for ammonia decomposition catalysts are their high cost and time-consuming preparation process. In this work, ammonia decomposition catalysts consisting of in situ-formed nano-Ru particles supported on a naturally abundant mineral fiber, attapulgite (ATP), were proposed and studied. Also, 1 wt.% Ru was uniformly dispersed and anchored onto the surface of ATP fibers via the chemical method. We found that the calcination temperatures of the ATP support before the deposition of Ru resulted in little difference in catalytic performance, while the calcination temperatures of the 1Ru/ATP precursor were found to significantly influence the catalytic performance. The prepared 1 wt.% Ru/ATP catalyst (1Ru/ATP) without calcination achieved an ammonia conversion efficiency of 51% at 500 °C and nearly 100% at 600 °C, with the flow rate of NH3 being 10 sccm (standard cubic centimeter per minute). A 150 h continuous test at 600 °C showed that the 1Ru/ATP catalyst exhibited good stability with a degradation rate of about 0.01% h−1. The 1Ru/ATP catalyst was integrated with proton ceramic fuel cells (PCFCs). We reported that PCFCs at 650 °C offered 433 mW cm−2 under H2 fuel and 398 mW cm−2 under cracked NH3 fuel. The overall results suggest low-level Ru-loaded ATP could be an attractive, low-cost, and efficient ammonia decomposition catalyst for hydrogen production. [ABSTRACT FROM AUTHOR]

Domain-based local pair natural orbital coupled cluster (DLPNO-CC) has become increasingly popular to calculate relative energies (e.g., reaction energies and reaction barriers). It can be applied within a multi-level DLPNO-CC-in-DLPNO-CC ansatz to reduce the computational cost and focus the available computational resources on a specific subset of the occupied orbitals. We demonstrate how this multi-level DLPNO-CC ansatz can be combined with our direct orbital selection (DOS) approach [M. Bensberg and J. Neugebauer, J. Chem. Phys. 150, 214106 (2019)] to automatically select orbital sets for any multi-level calculation. We find that the parameters for the DOS procedure can be chosen conservatively such that they are transferable between reactions. The resulting automatic multi-level DLPNO-CC method requires no user input and is extremely robust and accurate. The computational cost is easily reduced by a factor of 3 without sacrificing accuracy. We demonstrate the accuracy of the method for a total of 61 reactions containing up to 174 atoms and use it to predict the relative stability of conformers of a Ru-based catalyst. [ABSTRACT FROM AUTHOR]

The introduction of heteroatoms into manganese dioxide (MnO2) is an effective method to adjust the active site of electrochemical water oxidation catalysis. Although many modification methods for MnO2 have been studied in electrocatalytic oxygen evolution reaction (OER), few studies have focused on the influence of regulating different crystal forms of MnO2 on catalytic activity. This article prepared four different crystal forms of MnO2 (α-MnO2, β-MnO2, γ-MnO2 and δ-MnO2), and systematically studied the catalytic performance of the catalyst (x-MnO2-Ru) prepared by adding Ru to α-MnO2, β-MnO2, γ-MnO2 and δ-MnO2 for OER. The results of linear sweep voltammetry and chronopotentiometry measurements show that the catalyst prepared by adding Ru to β-MnO2 (β-MnO2-Ru) has the best electrochemical performance. β-MnO2 -Ru shows a low overpotential (300 mV at 10 mA·cm-2) and outstanding catalytic activity with small degradation after 24 h operation. It is found that β-MnO2-Ru exhibits excellent electrocatalytic performance due to its abundance of Mn3+ and defect oxygen vacancies. [ABSTRACT FROM AUTHOR]

We report the development of Ru/Mg–Al oxide coated metal-structured catalysts with excellent heat and mass transfer characteristics for efficient clean H 2 production from ammonia decomposition. Ammonia is a promising carrier for the mass transport of hydrogen and facilitates the production of COx-free hydrogen by decomposing into nitrogen and hydrogen. Ru nanoparticles are uniformly dispersed on the Mg–Al oxide layer of the FeCralloy monoliths and foams via precipitation. The catalytic activities depend on the surface area and loading of the catalysts and the metal dispersion in the oxide layer. At temperatures <650 °C, and a gas hourly space velocity (GHSV) of 3,000 h−1, monolithic catalysts with a large surface area and evenly distributed active metals perform excellently. Foam catalysts with excellent heat transfer performance better at temperatures >650 °C and GHSV >6,000 h−1. Foam catalyst stability is verified for 100 h in a 20 Nm3/h high-purity hydrogen production system. [Display omitted] • COx-free H 2 production via NH 3 decomposition on Ru-coated metal-structured catalysts. • Nano-sized Ru uniformly dispersed in plate-like Mg–Al oxide layers by precipitation. • Amount of Ru in the structured catalyst was <∼1/10 of that in the pellet catalyst. • Foams performed better catalytically than monoliths at higher GHSV (6,000 h−1). • Foam catalyst stability was verified in a 20 Nm3/h-H 2 production system for 100 h. [ABSTRACT FROM AUTHOR]

A series of Co–Ce–Al–O mesoporous catalysts synthesised by self-assembly is shown to be efficient for the hydrogen production via ammonia decomposition reaction. The evaporation-induced self-assembly method is utilised to effectively synthesise mesoporous multicomponent catalysts with tuned composition and improved performance. The prepared catalyst materials were characterised by several techniques including X-ray diffraction, scanning electron microscope, transmission electron microscope and N 2 physisorption analysis. The kinetic performance of the solid catalysts was evaluated at different temperatures and flow rates under atmospheric pressure. The optimised Co 0.5 Ce 0.1 Al 0.4 O(sa) catalyst remained highly active below 550 °C which represents a competitive performance among state-of-the-art catalysts. The promising performance of the catalyst and the use of nonprecious metals in the structure represent a feasible approach towards the application of ammonia as a hydrogen carrier for on-board hydrogen production. [Display omitted] • The Co–Ce–Al–O mesoporous catalyst is prepared using a self-assembly method for ammonia decomposition. • Ammonia conversion of 98% was obtained at 550 °C with the GHSV of 12,000 mL h−1 g cat −1. • Cerium promoted the catalyst activity, and aluminium enhanced the catalyst stability. • The Co–Ce–Al–O catalytic performance is comparable to Ru-based catalysts. [ABSTRACT FROM AUTHOR]

The integration of dual asymmetric catalysis is highly beneficial for the synthesis of organic molecules with multiple stereocenters. However, two major issues that need to be addressed are the intrinsic deactivation of dual-species and the extrinsic conflict of reaction conditions. To overcome these concerns, we have utilized the compartmental and thermoresponsive properties of poly(N-isopropylacrylamide) (PNIPAM) to develop a cross-linked PNIPAM-hydrogel-supported bifunctional catalyst. This catalyst is designed with Rh(diene) species situated on the outer surface and Ru(diamine) species positioned within the interior of the hydrogel. The compartmental function of PNIPAM in the middle overcomes intrinsic mutual deactivations between the dual-species. The thermoresponsive nature of PNIPAM allows for precise control of catalytic pathways in resolving external conflicts by controlling the reaction switching between an Rh-catalyzed enantioselective 1,4-addition at 50°C and a Ru-catalyzed asymmetric transfer hydrogenation (ATH) at 25°C. As we envisioned, this sequential 1,4-addition/reduction dual enantioselective cascade reaction achieves a transformation from incompatibility to compatibility, resulting in direct access to γ-substituted cyclic alcohols with dual stereocenters in high yields and enantio/diastereoselectivities. Mechanistic investigation reveals a reversible temperature transition between 50°C and 25°C, ensuring a cascade process comprising a 1,4-addition followed by the ATH process. Dual asymmetric catalysis is powerful for the synthesis of multi-stereocenter molecules, however, the integration of dual catalysts remains challenging due to the intrinsic deactivation of dual-species and extrinsic conflict of reaction conditions. Here, the authors develop a compartmental and thermoresponsive poly(N-isopropylacrylamide)-hydrogel-supported bifunctional catalyst to overcome these challenges. [ABSTRACT FROM AUTHOR]

Crystalline phase engineering is a prominent strategy for synergistically optimizing the surface–body phases of a catalyst. In this work, TiO2 nanosheets assembled into nanotubes (TNSTs) with two phases, anatase and rutile, were firstly synthesized via crystal engineering by simple thermal annealing. These were subsequently loaded with Ru nanoparticles, with a mean size of 5.0 nm, to create the efficient benzene hydrogenation catalyst Ru/TNSTs. The well-designed nanosheet-tube structure boasts a large specific surface area and excellent transmission channels, which effectively prevents the agglomeration and deactivation of loaded Ru nanoparticles, as well as promoting the internal diffusion in the reaction process of benzene hydrogenation to cyclohexene. Furthermore, titanium dioxide nanosheet-tubes contain numerous Ti3+ defects, which not only improves the overall conversion rate of cyclohexene but also enhances the suppression of cyclohexene adsorption. Most importantly, the titanium dioxide with its two-phase composition of 75 wt% anatase and 25 wt% rutile increases the ratio of electron deficiencies of Ru and promotes cyclohexene desorption. These synergistic properties enhance the selectivity and efficiency of the Ru/TNSTs catalysts, resulting in excellent performance in the hydrogenation of benzene to cyclohexene. In particular, the Ru/TNSTs-4 catalyst (annealed for 4 h), under the specific conditions of 140 °C temperature and 5 MPa hydrogen pressure for the hydrogenation process, achieves a 95% initial selectivity and 51% yield of cyclohexene in the reaction, outperforming most supported Ru-based catalysts. This work may provide new perspectives for designing efficient benzene hydrogenation catalysts via crystalline phase engineering. [ABSTRACT FROM AUTHOR]

Cobalt-iron bimetallic catalysts promoted with Nb, Ru or Rh and supported on multiwalled-carbon nanotubes (MWCNTs) were synthesized using a reverse-microemulsion method. The synthesized catalysts were characterized by TEM, N2-physical adsorption, XPS, XRD, and TPD/R/O methods. XPS analyses showed an increasing trend of the Co2+/Co3+ atomic ratios for the promoted catalysts, compared to that of the un-promoted Co–Fe/CNTs catalyst. The dispersion for the un-promoted Co–Fe /CNTs catalyst was 15.9% and it increased to 23.0, 20.4, and 17.7% in the presence of 0.1 wt.% Nb, Ru, and Rh promoter, respectively. The addition of Nb-promoter also improved the reducibility of the catalyst as exhibited by the H2-TPR study. The presence of Nb, Ru, and Rh promoters improved the catalytic performance in a Fischer–Tropsch synthesis where the TOF over the un-promoted catalyst increased from 5.1 to 6.2, 5.7, 5.2 × 10–1 s−1 upon the addition of Nb, Ru and Rh promoter, respectively. Thus, the Nb promoter was a better promoter than Ru and Rh for the Co–Fe/CNTs catalyst. [ABSTRACT FROM AUTHOR]

This study introduces an efficient strategy for promoting the synthesis of γ-valerolactone (GVL) via levulinic acid (LA) hydrogenation. A series of hyper-crosslinked porous polymer (HCP) supported Ru catalysts with different monomers were prepared. The wettabilities were controlled by the surface functional groups. The hydrophobic catalysts showed much higher activity than the hydrophilic ones in the hydrogenation of LA to GVL, highly possible due to the substrate enrichment. Further insight showed that the reaction proceeded through the 4-HVA route. These results illustrated the importance of surface wettability in bio-based molecule upgrading, which is beneficial for catalyst design. [ABSTRACT FROM AUTHOR]

By rationally adjusting the coordination environment and constructing the more electron‐enriched active site in single‐atom catalysts, the effect of heterogenous peroxymonosulfate (PMS)‐based Fenton‐like reactions can be effectively improved, yet remains a severe challenge. In this study, the electron‐rich Ru dual‐atom site is successfully immobilized onto N‐doped carbon (Ru2N6‐C) for PMS activation in water purification. The presence of electron‐rich Ru dual‐atom sites not only provides more electrons for PMS but also facilitates the formation of a Yeager adsorption configuration on the catalyst surface, which enhances O─O bond cleavage and leads to an increase in •SO4− and •OH generation. Moreover, the Ru2N6‐C catalyst exhibits exceptional durability and reliability, achieving an ultra‐high efficiency with a turnover frequency of 153.95 min−1 M−1 for the naproxen degradation. A membrane reactor is further developed for the purification of wastewater, which is expected to provide a viable approach to controlling water pollution through the design of metal dual‐atom sites carbon‐based catalysts. [ABSTRACT FROM AUTHOR]

The thermal treatment is one of the key procedures for the distribution and transformation of active sites for the supported metal oxide catalysts. However, the underlying impacts of thermal treatment on composite supported catalysts receives limited attention due to the additional complexity of the composite support. In this work, the progressive gradient in the metathesis activity, as the function of enhanced calcination temperature, has been observed for the tungsten‐based catalysts supported on the hierarchical ZSM‐5 zeolite‐alumina composite. The metathesis activity, reflected by ethene conversion, undergoes a stepwise growth from 24.2 % to 38.9 % along with the enhanced calcination temperature from 723 K to 923 K. The supported W‐oxo species share high similarity in structural states except their interaction with the Brønsted acidic bridge hydroxyl groups in zeolite. The density of bridge hydroxyl groups is reduced as the function of enhanced calcination temperatures, which reflects the intensified anchoring of surface W‐oxo species. It should be noted that such dependence is not observed for their counterparts based on microporous ZSM‐5 zeolite‐alumina. These sharp comparisons highlight the critical routes of thermal migration of W‐oxo species along the intrazeolite‐alumina interface in the evolution of active sites for the olefins cross‐metathesis reaction. [ABSTRACT FROM AUTHOR]

Bifunctional catalysts are a major type of heterogeneous catalytic systems that have been widely investigated for biomass upgrading. In this work, Ru-catalysts based on sulfonated porous aromatic frameworks (PAFs) were used in the hydrodeoxygenation (HDO) of lignin-derived compounds: guaiacol, veratrole, and catechol. The relationship between the activity of metal nanoparticles and the content of acid sites in synthesized catalysts was studied. Herein, their synergy was demonstrated in the Ru-PAF-30-SO3H/5-COD catalyst. The results revealed that this catalytic system promoted partial hydrogenation of lignin-based compounds to ketones without any further transformations. The design of the Ru-PAF-30-SO3H/5-COD catalytic system opens a promising route to the selective conversion of lignin model compounds to cyclohexanone. [ABSTRACT FROM AUTHOR]

Hydrogen has emerged as an important candidate for clean energy, owing to its environmentally friendly advantages. Electrolytic hydrogen production stands out as the most promising technology for hydrogen production. Therefore, the design of highly efficient electrocatalysts is significant to drive the application of hydrogen technologies. Platinum (Pt)-based catalysts are famous for their outstanding performance in the hydrogen evolution reaction (HER). However, the expensive cost limits its wide application. Ruthenium (Ru)-based catalysts have received extensive attention due to their relatively lower cost and HER performance similar to that of Pt. Nevertheless, the performance of Ru-based catalysts is still unable to meet industrial demands. Therefore, improving HER performance through the modification of Ru-based catalysts remains significant. In this review, the reaction mechanism of HER is analyzed and the latest research progress in the modification of Ru-based electrocatalysts is summarized. From the reaction mechanism perspective, addressing the adsorption of intermediates on the Ru-based electrocatalyst surface, the adsorption–activation of interface water molecules, and the behavior of interface water molecules and proposing solutions to enhance performance of Ru-based electrocatalyst are the main findings, ultimately contributing to promoting their application in the field of electrocatalysis. [ABSTRACT FROM AUTHOR]

Ruthenium nanoparticles (NPs) immobilized on an amine‐functionalized polymer‐grafted silica support act as adaptive catalysts for the hydrogenation of bicyclic heteroaromatics. Whereas full hydrogenation of benzofuran and quinoline derivatives is achieved under pure H2, introducing CO2 into the H2 gas phase leads to an effective shutdown of the arene hydrogenation while preserving the activity for the hydrogenation of the heteroaromatic part. The selectivity switch originates from the generation of ammonium formate species on the surface of the materials by catalytic hydrogenation of CO2. The CO2 hydrogenation is fully reversible, resulting in a robust and rapid switch between the two states of the catalyst adapting its performance in response to the feed gas composition. A variety of benzofuran and quinoline derivatives were hydrogenated to fully or partially saturated products in high selectivity and yields simply by altering the composition of the feed gas from H2 to H2/CO2. The adaptive catalytic system thus provides controlled access to valuable products using a single catalyst rather than two specific and distinct catalysts with static reactivity. [ABSTRACT FROM AUTHOR]

Ethylene glycol metal carboxylates are suited as low‐temperature precursors for M and MxOy nanoparticle formation, which are applicable in catalytic heterogeneous reactions including hydrogenations, hydrometalations or C,C cross‐couplings. For the synthesis of β‐oxo‐propyl and enol esters [Ru(CO)2(PPh3)2(O2CR)2] complexes are excellent homogeneous catalysts with high regioselectivities. Additionally, applications of the title complexes beyond catalysis are presented. [ABSTRACT FROM AUTHOR]

Herein, we report a ruthenium‐catalyzed ketone directed ortho‐arylation wherein the addition of a bidentate NC‐type ligand, most effectively 2‐(o‐tolyl) pyridine, significantly enhances the C−H arylation reaction. Various aryl‐alkyl ketones, including cyclic, aliphatic, and heterocyclic ones, are competent substrates, and arylboronic acid esters were used as aryl sources. However, substitution with OMe and CF3 in the aromatic ring of the ketone substrates is not tolerated, while such residues on the benzoic ester are possible. Notably, this study provides valuable insights into ketone‐directed ortho arylation in the presence of 2‐(o‐tolyl) pyridine and adds additional options for catalyst and ligand optimization in ruthenium‐catalyzed C−H functionalization. [ABSTRACT FROM AUTHOR]

The development of a rational protocol to realize the complete regioselectivity and the capability to switch regioselectivity is an appealing yet challenging task. Herein, a regiodivergent C−H arylation of 2‐pyridylthiophenes has been demonstrated via the choice of RuII and PdII catalysts. The reactions proceeded smoothly in a good regioselective manner to afford the corresponding C3‐ and C5‐arylated thiophenes. Late‐stage diversification of biologically relevant scaffold derived from estrone and successful transformation of the products further highlighted the potential utility and importance of this synthetic strategy. [ABSTRACT FROM AUTHOR]

The high cost of noble metals is one of the key factors hindering the large‐scale application of proton exchange membrane (PEM) water electrolyzer for hydrogen production. Recently, single‐atom catalysts (SACs) with a potential of maximum atom utilization efficiency enable lowering the metal amount as much as possible; unfortunately, their durability remains a challenge under PEM water electrolyzer working conditions. Herein, a highly‐stable alloyed Pt SAC is demonstrated through a plasma‐assisted alloying strategy and applies to a PEM water electrolyzer. In this catalyst, single Pt atoms are firmly anchored onto a Ru support via a robust metal–metal bonding strength, as evidenced by these complementary characterizations. This SAC is used in a PEM water electrolyzer system to achieve a cell voltage as low as 1.8 V at 1000 mA cm−2. Impressively, it can operate over 1000 h without obvious decay, and the catalyst is present in the form of individual Pt atoms. To the knowledge, this will be the first SAC attempt at a cell level toward long‐term PEM. This work paves the way for designing durable SACs employed in the actual working condition in the PEM water electrolyzer. [ABSTRACT FROM AUTHOR]

Single‐atom catalysts (SACs) have emerged as crucial players in catalysis research, prompting extensive investigation and application. The precise control of metal atom nucleation and growth has garnered significant attention. In this study, we present a straightforward approach for preparing SACs utilizing a photocatalytic radical control strategy. Notably, we demonstrate for the first time that radicals generated during the photochemical process effectively hinder the aggregation of individual atoms. By leveraging the cooperative anchoring of nitrogen atoms and crystal lattice oxygen on the support, we successfully stabilize the single atom. Our Pd1/TiO2 catalysts exhibit remarkable catalytic activity and stability in the Suzuki–Miyaura cross‐coupling reaction, which was 43 times higher than Pd/C. Furthermore, we successfully depose Pd atoms onto various substrates, including TiO2, CeO2, and WO3. The photocatalytic radical control strategy can be extended to other single‐atom catalysts, such as Ir, Pt, Rh, and Ru, underscoring its broad applicability. [ABSTRACT FROM AUTHOR]

Precision polishing using transition metal catalysts such as Pt and Ru, called catalyst-refereed etching, is employed to fabricate atomically smooth surfaces on optical devices, realizing the designed device performance. However, the catalyst surface is covered with post-processing products during processing, drastically decreasing the removal rate. To address this issue, this paper proposes using an Ru-based alloy catalyst. Density functional theory calculation results show that doping Ti to Ru significantly reduces the adsorption energy of post-processing products, suggesting that the active site of the catalyst is easily recovered. When polishing silica glass, the Ru 2 Ti catalyst significantly improves the removal rate stability and enables the fabrication of an atomically well-ordered smooth surface, similar to that polished using a Pt or Ru catalyst. • An Ru-based alloy catalyst is proposed for precision polishing of optics components. • Density functional theory calculations were performed to verify its effectiveness. • The considered Ru 2 Ti catalyst significantly improves the removal rate stability. • Doping Ti to Ru reduces the adsorption energy of the post-processing products. • The catalyst also enables the fabrication of atomically well-ordered smooth surfaces. [ABSTRACT FROM AUTHOR]

Novel catalysts for efficient formation of liquid organic hydrogen carriers (LOHCs) used in hydrogen storage and transport show great promise. Although Pt–Ru alloys have exhibited catalytic activities superior to those of Pt in the hydrogenation of toluene to methylcyclohexane, the origins are still unclear. Herein, we use density functional theory (DFT) to examine the mechanisms for toluene hydrogenation on Pt and various Pt–Ru bimetallic catalysts. The core@shell-type Ru@Pt(111) shows more thermodynamically and kinetically favored hydrogenation of toluene than pure Pt or Pt–Ru ordered structures. The origin of the improved catalytic activity on Ru@Pt(111) is examined by separating the strain and ligand effects between the core and shell layers. The ligand effect lowers the d-band center more pronouncedly; moreover, the favorable charge gain on the surface lowers the binding energies of reaction intermediates as well as the activation energies for each hydrogenation step. This work provides insight into the design of novel catalysts providing LOHCs for efficient hydrogen storage. [Display omitted] • Hydrogenation of toluene to methylcyclohexane on Pt and Pt–Ru catalysts was studied. • Ru@Pt(111) tunes the hydrogenation mechanism and favors the catalytic activity. • Ru@Pt(111) surface lowers the energy of the d-band center the most. • Ligand effect of Ru@Pt induces a favorable charge gain on the surface. [ABSTRACT FROM AUTHOR]

The tunability of reaction pathways is required for exploring efficient and low cost catalysts for ammonia synthesis. There is an obstacle by the limitations arising from scaling relation for this purpose. Here, we demonstrate that the alkali earth imides (AeNH) combined with transition metal (TM = Fe, Co and Ni) catalysts can overcome this difficulty by utilizing functionalities arising from concerted role of active defects on the support surface and loaded transition metals. These catalysts enable ammonia production through multiple reaction pathways. The reaction rate of Co/SrNH is as high as 1686.7 mmol·gCo−1·h−1 and the TOFs reaches above 500 h−1 at 400 °C and 0.9 MPa, outperforming other reported Co-based catalysts as well as the benchmark Cs-Ru/MgO catalyst and industrial wüstite-based Fe catalyst under the same reaction conditions. Experimental and theoretical results show that the synergistic effect of nitrogen affinity of 3d TMs and in-situ formed NH2− vacancy of alkali earth imides regulate the reaction pathways of the ammonia production, resulting in distinct catalytic performance different from 3d TMs. It was thus demonstrated that the appropriate combination of metal and support is essential for controlling the reaction pathway and realizing highly active and low cost catalysts for ammonia synthesis. The presence of electrically active defects on the surface of the support has been shown to be effective for N2 activation. Here the authors discover that electron-rich polyanionic NH2− defect allows for efficient ammonia synthesis via multiple reaction pathway by incorporating various affordable transition metals. [ABSTRACT FROM AUTHOR]

The fundamental insights of the reaction mechanism, especially the synergistic effect between oxygen vacancies and basic sites, are highly promising yet challenging for Ru-based catalysts during carbon dioxide (CO2) methanation. Herein, a series of Ru-based catalysts were employed to study the mechanism of CO2 methanation. It is found that Ru/CeO2 catalyst exhibits a much higher CO2 conversion (86%) and CH4 selectivity (100%), as well as excellent stability of 30 h due to the existence of abundant oxygen vacancies and weak basic sites. Additionally, the in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT) calculations reveal that the formate formation step dominated the hydrogenation route on Ru/CeO2 catalyst, and the b-HCOO* could be the key intermediate due to b-HCOO* is more easily hydrogenated to methane than m-HCOO*. The systematic study marks the significance of precise tailoring of the synergistic relationship between oxygen vacancies and basic sites for achieving the desired performance in CO2 methanation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ru-Co 3 O 4 Mott-Schottky catalyst is designed and successful constructed. • Mott-Schottky effect is favorable for the activation of reactant molecules. • Ru-Co 3 O 4 exhibits the excellent catalytic performance for the AB dehydrogenation. • Ru-Co 3 O 4 achieves a high HGR of 12238 mL min−1 g cat -1. • Ru-Co 3 O 4 delivers a high TOF of 755 mol H2 mol Ru -1 min−1. Developing efficient catalysts for the dehydrogenation of ammonia borane (AB) is important for the safe storage and controlled release of hydrogen, but it is a challenging task. In this study, we designed a robust Ru-Co 3 O 4 catalyst using the Mott-Schottky effect to induce favorable charge rearrangement. The self-created electron-rich Co 3 O 4 and electron-deficient Ru sites at heterointerfaces are indispensable for the activation of the B-H bond in NH 3 BH 3 and the O H bond in H 2 O, respectively. The synergistic electronic interaction between the electron-rich Co 3 O 4 and electron-deficient Ru sites at the heterointerfaces resulted in an optimal Ru-Co 3 O 4 heterostructure that exhibited outstanding catalytic activity for the hydrolysis of AB in the presence of NaOH. The heterostructure had an extremely high hydrogen generation rate (HGR) of 12238 mL min−1 g cat -1 and an expected high turnover frequency (TOF) of 755 mol H2 mol Ru -1 min−1 at 298 K. The activation energy needed for the hydrolysis was low (36.65 kJ mol−1). This study opens up a new avenue for the rational design of high-performance catalysts for AB dehydrogenation based on the Mott-Schottky effect. [ABSTRACT FROM AUTHOR]

The utilization of stimuli-responsive hydrogels as bifunctional catalysts for an aqueous sequential organic transformation to prepare chiral organic molecules is not only environmentally friendly, but also complements the synthetic limitations of mutually contradictory multistep reactions. However, finding a solution to the incompatible issue arising from complicated multicomponent cross-interactions in sequential transformations is a significant challenge. To address this issue, we have developed a core–shell-structured hydrogel as a site-isolated bifunctional catalyst. This catalyst features thermoresponsive poly(N-isopropylmethacrylamide) with a switching function via a reversible transition between its hydrogel and solution phases that perfectly matches a temperature-tuned base-catalyzed aldol condensation/oxa-Michael addition at 70 °C and the ruthenium-catalyzed dynamic kinetic resolution asymmetric transfer hydrogenation (DKR-ATH) process at 40 °C. As we envisioned, through the harmonization of the conflicting sequential reactions, this aldol condensation/oxa-Michael addition/DKR-ATH cascade process can be achieved by transitioning from being incompatible to compatible, enabling direct access to chiral chromanols with 1,3-positioned dual stereocenters from commercially available ortho-hydroxyl arylketones and aldehydes. Mechanistic investigations, which involve monitoring the cascade reaction and analyzing the deuterium-labeling experiments, reveal a domino-like aldol condensation/oxa-Michael addition/DKR-ATH sequential route comprising an initial aldol condensation/oxa-Michael addition followed by the subsequent DKR-ATH process. [ABSTRACT FROM AUTHOR]