Ru Single Atoms Research Articles

All-round enhancement induced by oxophilic single Ru and W atoms for alkaline hydrogen oxidation of tiny Pt nanoparticles

Anion exchange membrane fuel cells (AEMFCs) are one of the ideal energy conversion devices. However, platinum (Pt), as the benchmark catalyst for the hydrogen oxidation reaction (HOR) of AEMFCs anodes, still faces issues of insufficient performance and susceptibility to CO poisoning. Here, we report the Joule heating-assisted synthesis of a small sized Ru1Pt single-atom alloy catalyst loaded on nitrogen-doped carbon modified with single W atoms (s-Ru1Pt@W1/NC), in which the near-range single Ru atoms on the Ru1Pt nanoparticles and the long-range single W atoms on the support simultaneously modulate the electronic structure of the active Pt-site, enhancing alkaline HOR performance of s-Ru1Pt@W1/NC. The mass activity of s-Ru1Pt@W1/NC is 7.54 A mgPt+Ru-1 and exhibits notable stability in 1000 ppm CO/H2-saturated electrolyte. Surprisingly, it can operate stably in H2-saturated electrolyte for 1000 h with only 24.60 % decay. Theoretical calculations demonstrate that the proximal single Ru atoms and the remote single W atoms synergistically optimize the electronic structure of the active Pt-site, improving the HOR activity and CO tolerance of the catalyst.

Tuning the local S coordination environment on Ru single atoms to boost the oxygen evolution reaction.

Engineering the local electronic structure of single atom catalysts (SACs) still remains challenging. In this study, a Ru-NiS2 single atom catalyst with a controlled S coordination environment, where Ru single atoms are implanted on a NiS2 nanoflower consisting of plenty of cross-linked nanosheets, has been developed via a facile atom capture strategy. Using Density Functional Theory (DFT) calculations, it has been revealed that the fine-tuned local S coordination environment can optimize the electronic structure of Ru active sites, and reduce the energy barrier of the rate-determining step for the oxygen evolution reaction (OER), thus boosting the electrocatalytic activity, such as a low overpotential of 269 mV at 10 mA cm-2. This work provides new insights into the rational regulation of the local coordination environment for SACs.

Evolution of amorphous ruthenium nanoclusters into stepped truncated nano-pyramids on graphitic surfaces boosts hydrogen production from ammonia.

Atomic-scale changes can significantly impact heterogeneous catalysis, yet their atomic mechanisms are challenging to establish using conventional analysis methods. By using identical location scanning transmission electron microscopy (IL-STEM), which provides quantitative information at the single-particle level, we investigated the mechanisms of atomic evolution of Ru nanoclusters during the ammonia decomposition reaction. Nanometre-sized disordered nanoclusters transform into truncated nano-pyramids with stepped edges, leading to increased hydrogen production from ammonia. IL-STEM imaging demonstrated coalescence and Ostwald ripening as mechanisms of nanocluster pyramidalization during the activation stage, with coalescence becoming the primary mechanism under the reaction conditions. Single Ru atoms, a co-product of the catalyst activation, become absorbed by the nano-pyramids, improving their atomic ordering. Ru nano-pyramids with a 2-3 nm2 footprint consisting of 3-5 atomic layers, ensure the maximum concentration of active sites necessary for the rate-determining step. Importantly, the growth of truncated pyramids typically does not exceed a footprint of approximately 4 nm2 even after 12 hours of the reaction, indicating their high stability and explaining ruthenium's superior activity on nanotextured graphitic carbon compared to other support materials. The structural evolution of nanometer-sized metal clusters with a large fraction of surface atoms is qualitatively different from traditional several-nm nanoparticles, where surface atoms are a minority, and it offers a blueprint for the design of active and sustainable catalysts necessary for hydrogen production from ammonia, which is becoming one of the critical reactions for net-zero technologies.

Ru single atoms in Mn2O3 efficiently promote the catalytic oxidation of 5-hydroxymethylfurfural through dual activation of lattice and molecular oxygen

Ru single atoms in Mn2O3 efficiently promote the catalytic oxidation of 5-hydroxymethylfurfural through dual activation of lattice and molecular oxygen

Ru single atom modified DUT-67(Zr) with unsaturated Zr for high-efficiency photocatalytic nitrogen reduction

Ru single atom modified DUT-67(Zr) with unsaturated Zr for high-efficiency photocatalytic nitrogen reduction

Ru-OV Site-Mediated Product Selectivity Switch for Overall Photocatalytic CO2 Reduction.

The photocatalytic reduction of carbon dioxide (CO2) to methane (CH4) represents a sustainable route for directly converting greenhouse gases into chemicals but poses a significant challenge in achieving high selectivity due to thermodynamic and kinetic limitations during the reaction process. This work establishes Ru-OV active sites on the surface of TiO2 by anchoring coordination unsaturated Ru single-atoms, which stabilize crucial reaction intermediates and facilitate local mass transfer to achieve dual optimization of the thermodynamics and kinetics of the overall photocatalytic CO2 reduction. Combining operando spectroscopy with density functional theory (DFT)calculations indicates that oxygen vacancies (OV) inhibits the desorption of *CO, whereas Ru facilitates proton extraction. This configuration not only lowers the overall activation energy barrier but has also been engineered to serve as a selectivity switch, changing the reaction route to produce CH4 instead of CO. Consequently, the Ru-OV/TiO2 exhibits a 195.4-fold improvement in the CH4 yield compared to TiO2, accompanied by an increase in selectivity to 81%.

Unraveling the Harmonious Coexistence of Ruthenium States on a Self-Standing Electrode for Enhanced Hydrogen Evolution Reaction

The development of cost-effective, highly efficient, and durable electrocatalysts has been a paramount pursuit for advancing the hydrogen evolution reaction (HER). Herein, a simplified synthesis protocol was designed to achieve a self-standing electrode, composed of activated carbon paper embedded with Ru single-atom catalysts and Ru nanoclusters (ACP/RuSAC+C) via acid activation, immersion, and high-temperature pyrolysis. Ab initio molecular dynamics (AIMD) calculations are employed to gain a more profound understanding of the impact of acid activation on carbon paper. Furthermore, the coexistence states of the Ru atoms are confirmed via aberration-corrected scanning transmission electron microscopy (AC-STEM), X-ray photoelectron spectroscopy (XPS), and X-ray absorption spectroscopy (XAS). Experimental measurements and theoretical calculations reveal that introducing a Ru single atom site adjacent to the Ru nanoclusters induces a synergistic effect, tuning the electronic structure and thereby significantly enhancing their catalytic performance. Notably, the ACP/RuSAC+C exhibits a remarkable turnover frequency (TOF) of 18 s-1 and an exceptional mass activity (MA) of 2.2 A mg-1, surpassing the performance of conventional Pt electrode. The self-standing electrode, featuring harmoniously coexisting Ru states, stands out as a prospective choice for advancing HER catalysts, enhancing energy efficiency, productivity, and selectivity. Figure 1

Monolayer Amphiphiles Hydrophobicize MoS2-Mediated Real-Time Water Removal for Efficient Waterproof Hydrogen Detection.

Ensuring water-fouling-free operation of semiconductor-based gas sensors is essential to maintaining their accuracy, reliability, and stability across diverse applications. Despite the use of hydrophobic strategies to prevent external water intrusion, addressing in situ-produced water transport during H2 detection remains a challenge. Herein, we construct a novel waterproof H2 sensor by integrating single-atom Ru(III) self-assembly with monolayer amphiphiles embedded in MoS2. The unique monolayer structure enables the sensor to detect H2 in the presence of water, as well as facilitate the self-transport of in situ-generated water from the H2-O2 reaction during H2 detection. Molecular dynamics simulations reveal that monolayer amphiphiles exhibit a higher water diffusion coefficient than multilayer amphiphiles, making them more advantageous for removing in situ-produced water. Deployable on mobile platforms, it enables wireless H2cat detection for up to 6 months, without the introduction of protective membranes against dust and water ingress. This work not only enhances the performance of H2 detection but also introduces a new concept for the advancement of stable water-sensitive sensors.

Single-atom ruthenium nanozyme-induced signal amplification strategy in photoelectrochemical aptasensor for ultrasensitive detection of chloramphenicol

To develop ultrasensitive and rapid antibiotics residue detection method is crucial for ensuring food safety and protecting human health. Herein, a novel photoelectrochemical (PEC) aptasensor integrated with single-atom ruthenium (Ru) nanozyme-mediated catalytic precipitation as a valuable signal amplification strategy, have been established for ultrasensitive chloramphenicol (CAP) detection. Particularly, the exceptional peroxidase-mimicking activity of single-atom Ru nanozyme is responsible for accelerating the oxidation of 4-chloro-1-naphthol (4-CN) to produce insoluble precipitate on the electrode, which in turn causes a notable reduction in the photocurrent. Whereas, when CAP is present, the aptamer is liberated away the electrode because of its potent affinity with CAP, resulting in an elevation of the photocurrent signal, enhancing the detection sensitivity. Importantly, the signal amplification strategy combines the effective photoactive material of Au nanoparticles/CdS quantum dot/TiO2 composites, a PEC aptasensor for determination of CAP with an ultralow detection limit of 4.12 pM is achieved in a self-powered mode with great selectivity and accuracy. This work proposes a novel reasonable approach utilizing high-activity single-atom nanozyme to induce signal amplification strategy for the advancement of single-atom nanozyme in ultrasensitive PEC biosensor, and further creates new avenues for ultrasensitive detection beyond antibiotics residue.

Band gap effect of TiO2 on supported Ru single-atom catalysts for CO2 methanation by DFT calculations

The influence of TiO2 band gap on structure and reactivity of the supported single ruthenium (Ru1) atom was studied by density functional theory calculations, utilizing Ru1/2L-TiO2 and Ru1/3L-TiO2 as model catalysts for CO2 methanation. The supports have band gaps of 2.39 eV and 1.48 eV, respectively. The band gap plays a significant role in electronic metal-support interactions (EMSIs) and the position of the d-band center of the Ru1 on the TiO2. The Ru1/3L-TiO2, the Ru1 catalyst supported on the 3L-TiO2 with a narrower band gap, shows enhanced EMSIs and a d-band center that is positioned farther from Fermi level, leading to lower charge density on the Ru1 and weaker adsorption of H2, CO2, and CO compared to the Ru1/2L-TiO2. CO2 methanation followed CO pathway, with the hydrogenation of CO* to HCO* identified as the rate-determining step on the Ru1/nL-TiO2. The Ru1 catalyst supported on TiO2 with a narrower band gap is more favorable kinetically and thermodynamically for CO2 methanation, despite the band gap not altering the reaction pathway. Enhanced hydrogen mobility and a pronounced promotional effect of hydrogen on CO adsorption, due to the narrower band gap support, are key factors facilitating the easier hydrogenation of CO* on the Ru1/3L-TiO2.

Local compressive strain-induced anti-corrosion over isolated Ru-decorated Co3O4 for efficient acidic oxygen evolution

Enhancing corrosion resistance is essential for developing efficient electrocatalysts for acidic oxygen evolution reaction (OER). Herein, we report the strategic manipulation of the local compressive strain to reinforce the anti-corrosion properties of the non-precious Co3O4 support. The incorporation of Ru single atoms, larger in atomic size than Co, into the Co3O4 lattice (Ru-Co3O4), triggers localized strain compression and lattice distortion on the Co-O lattice. A comprehensive exploration of the correlation between this specific local compressive strain and electrocatalytic performance is conducted through experimental and theoretical analyses. The presence of the localized strain in Ru-Co3O4 is confirmed by operando X-ray absorption studies and supported by quantum calculations. This local strain, presented in a shortened Co-O bond length, enhances the anti-corrosion properties of Co3O4 by suppressing metal dissolutions. Consequently, Ru-Co3O4 shows satisfactory stability, maintaining OER for over 400 hours at 30 mA cm−2 with minimal decay. This study demonstrates the potential of the local strain effect in fortifying catalyst stability for acidic OER and beyond.

The Reaction Mechanism and Rates at Ru Single-Atom Catalysts for Hydrogenation of Biomass BHMF to Produce BHMTHF for Renewable Polymers.

Realizing high selectivity for producing biodegradable 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF) for renewable polymers from 5-hydroxymethylfurfural (HMF) biomass through ring hydrogenation on single-atom catalysts poses a considerable challenge due to the complexity of HMF functional groups and the difficulty of H2 dissociation. We developed a detailed reaction mechanism based on ab initio molecular dynamics (AIMD) and quantum mechanics (QM) to find that Ru single-atom catalysts can simultaneously dissociate H2 and perform the ring hydrogenation of biomass-derived 2,5-bis(hydroxymethyl)furan (BHMF) to produce biodegradable BHMTHF, with a free energy barrier of 0.82 eV. The unique property of Ru single-atom sites enables H2 to dissociate easily on a single active site of Ru to participate directly in the reaction without diffusion. Furthermore, our predicted reaction rate from microkinetic analysis indicates that ring hydrogenation and side-chain hydrogenolysis are much faster than ring-opening hydrogenation over the range of 300-550 K. The product BHMTHF dominates with a selectivity of 98.9% at 300 and 78.4% at 550 K (the second product is 5-methylfurfural (5-MFA)). This study underscores the unique effectiveness of Ru single atoms in ring hydrogenation reactions using H2 as the hydrogen source, offering insights for the design of single-atom catalysts for other biomass reactions.

Ru single-atom nanozymes targeting ROS-ferroptosis pathways for enhanced endometrial regeneration in intrauterine adhesion therapy

Intrauterine adhesion (IUA) presents a significant challenge in gynecology, characterized by excessive fibrosis and compromised reproductive function, leading to severe infertility. Although biocompatible hydrogels integrated with stem cells offer a promising approach for IUA therapy, clinical applications remain limited. Recent studies have highlighted the role of ferroptosis and reactive oxygen species (ROS) in IUA pathogenesis, yet strategies targeting ferroptosis through antioxidant stress are underexplored. This study investigates the therapeutic effects and mechanisms of a Ru-Single-Atom Nanozyme (Ru-SAN) incorporated into chitosan hydrogel for treating IUA. Ru-SAN, which mimics the enzyme activities of catalase, superoxide dismutase, and glutathione peroxidase, effectively clears excess ROS and shows promise in treating oxidative stress-induced diseases. The results demonstrate the superior antioxidative capabilities of Ru-SAN, significantly suppressing the ROS-ferroptosis cycle at the injury site. This creates a favorable microenvironment for post-injury repair by inhibiting inflammation, enhancing mesenchymal-to-epithelial transformation, promoting angiogenesis, and polarizing M2 macrophages. Importantly, it mitigates adverse repair outcomes from inflammation and excessive collagen fiber deposition, ultimately restoring uterine glandular structures and thickness, thereby achieving the ultimate goal of restoring fertility and live birth rates. In conclusion, our study delineates a pioneering therapeutic approach leveraging the antioxidant properties of Ru-SAN to target ferroptosis, thereby offering an efficacious treatment for IUA.

Manufacturing Single‐Atom Alloy Catalysts for Selective CO2 Hydrogenation via Refinement of Isolated‐Alloy‐Islands

AbstractSingle‐atom alloy (SAA) catalysts exhibit huge potential in heterogeneous catalysis. Manufacturing SAAs requires complex and expensive synthesis methods to precisely control the atomic scale dispersion to form diluted alloys with less active sites and easy sintering of host metal, which is still in the early stages of development. Here, we address these limitations with a straightforward strategy from a brand‐new perspective involving the ‘islanding effect’ for manufacturing SAAs without dilution: homogeneous RuNi alloys were continuously refined to highly dispersed alloy‐islands (~1 nm) with completely single‐atom sites where the relative metal loading was as high as 40 %. Characterized by advanced atomic‐resolution techniques, single Ru atoms were bonded with Ni as SAAs with extraordinary long‐term stability and no sintering of the host metal. The SAAs exhibited 100 % CO selectivity, over 55 times reverse water‐gas shift (RWGS) rate than the alloys with Ru cluster sites, and over 3–4 times higher than SAAs by the dilution strategy. This study reports a one‐step manufacturing strategy for SAA's using the wetness impregnation method with durable high atomic efficiency and holds promise for large‐scale industrial applications.

Manufacturing Single-Atom Alloy Catalysts for Selective CO2 Hydrogenation via Refinement of Isolated-Alloy-Islands.

Single-atom alloy (SAA) catalysts exhibit huge potential in heterogeneous catalysis. Manufacturing SAAs requires complex and expensive synthesis methods to precisely control the atomic scale dispersion to form diluted alloys with less active sites and easy sintering of host metal, which is still in the early stages of development. Here, we address these limitations with a straightforward strategy from a brand-new perspective involving the 'islanding effect' for manufacturing SAAs without dilution: homogeneous RuNi alloys were continuously refined to highly dispersed alloy-islands (~1 nm) with completely single-atom sites where the relative metal loading was as high as 40 %. Characterized by advanced atomic-resolution techniques, single Ru atoms were bonded with Ni as SAAs with extraordinary long-term stability and no sintering of the host metal. The SAAs exhibited 100 % CO selectivity, over 55 times reverse water-gas shift (RWGS) rate than the alloys with Ru cluster sites, and over 3-4 times higher than SAAs by the dilution strategy. This study reports a one-step manufacturing strategy for SAA's using the wetness impregnation method with durable high atomic efficiency and holds promise for large-scale industrial applications.

Synergistic Alkaline Hydrogen Evolution Catalysis over MoC Triggered by Doping Single Ru Atoms

AbstractThe rational design of single atom‐based catalysts and precise elucidation of the synergistic interaction between the metal site and substrate are pivotal to identifying the real active sites and explicating the catalytic mechanisms at the atomic scale, thus contributing to the development of high‐performance catalysts for diverse industrial implementations. Herein, a Ru single‐atom doping strategy is developed to activate the MoC substrate with superior hydrogen evolution reaction (HER) activity in an alkaline medium. The atomically dispersed Ru sites are elaborately doped into MoC nanoparticles loaded on 3D N‐doped carbon nanoflowers (Ru‐SAs@MoC/NCFs hereafter). The experimental results and theoretical calculations manifest that the atomically isolated Ru dopants can effectively trigger the Mo sites with thermodynamically favorable water adsorption/dissociation energies and facilitate the OH− desorption on Ru sites and H adsorption on N sites, thus synergistically expediating the overall alkaline HER kinetics. As such, the well‐designed Ru‐SAs@MoC/NCFs demonstrate extraordinary HER activity with a low overpotential of 16 mV at 10 mA cm−2 in 1.0 m KOH electrolyte, outperforming Pt/C benchmark and a vast of molybdenum/ruthenium‐based HER catalysts reported to date. These findings disclose the alkaline HER mechanistic induced by the atomic doping modulation and suggest a design principle of high‐efficiency electrocatalysts via the atomic‐level manipulation leverage.

Enhanced Peroxidase-like Activity of Ruthenium-Modified Single-Atom-Thick A Layers in MAX Phases for Biomedical Applications.

Nanozymes have demonstrated significant potential as promising alternatives to natural enzymes in biomedical applications. However, their lower catalytic activity compared to that of natural enzymes has limited their practical utility. Addressing this challenge necessitates the development of innovative enzymatic systems capable of achieving specific activity levels of natural enzymes. In this study, we focus on enhancing the catalytic performance of nanozymes by introducing Ru atoms into the single-atom-thick A layer of the V2SnC MAX phase, resulting in the formation of V2(Sn0.8Ru0.2)C with Ru single-atom sites. The V2(Sn0.8Ru0.2)C MAX phase demonstrated an exceptional peroxidase-like specific activity of up to 1792.6 U mg-1, surpassing the specific activity of a previously reported horseradish peroxidase (HRP). Through X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) investigations, it has been revealed that both the V2C atom layers and single-atom-thick Sn readily accept a negative charge from Ru, leading to a reduction of the energy barrier for H2O2 adsorption. This discovery has enabled the successful application of V2(Sn0.8Ru0.2)C in the development of a lateral flow immunoassay for heart failure biomarkers, achieving a detection sensitivity of 4 pg mL-1. Additionally, V2(Sn0.8Ru0.2)C demonstrated exceptional broad-spectrum antibacterial efficacy. This study lays the groundwork for the precise design of MAX phase-based nanozymes with high specific activity, offering a viable alternative to natural enzymes for various applications.

Catalytic Hydrogenolysis of Lignin into Propenyl-monophenol over Ru Single Atoms Supported on CeO2 with Rich Oxygen Vacancies

Catalytic Hydrogenolysis of Lignin into Propenyl-monophenol over Ru Single Atoms Supported on CeO₂ with Rich Oxygen Vacancies

Atomically dispersed ruthenium single-atom alloy catalysts enabling efficient iodide oxidation reaction electrolysis in acidic media

Single-atom catalysts exhibit immense potential across diverse reactions, yet their synthesis and stability in acidic environments pose significant challenges. Herein, we introduce a facile one-step hydrothermal approach to fabricate Ru single-atom alloy catalysts (Ru SAAC) through the reaction of Ru and Ti precursors, followed by annealing in an argon atmosphere. Analysis via extended X-ray absorption fine structure spectroscopy and aberration-corrected scanning transmission electron microscopy confirms the atomically dispersed Ru alloy catalyst anchored on a TiO2 support. Remarkably, Ru SAAC demonstrates exceptional electrocatalytic performance in the iodide oxidation reaction (IOR), achieving a benchmark current density of 10 mA/cm2 at a mere voltage of 0.64 V in acidic conditions within a three-electrode electrolyzer setup. Surpassing nanoscale Ru/TiO2 and RuO2/TiO2 counterparts, Ru SAAC exhibits the highest voltage efficiency (84.4%), lowest Tafel slope (36 mV/dec), and lowest overpotential (100 mV) under identical experimental conditions. This method enables facile control over Ru morphology. It enhances the kinetics and thermodynamic favorability of Ru SAAC in acidic media, opening avenues for synthesizing diverse transition metal-based single-alloy catalysts for varied applications.

Insight into the Coordination Environment of Ru Single-Atom for Dry Reforming of Methane.

Dry reforming of methane (DRM), a pivotal process for converting greenhouse gases into syngas is demanding rationally designed catalysts with high stability and ideal catalytic performance for industrial applications due to its stability of reactant molecules and characteristic of carbon deposition. However, the mechanistic understanding of how the coordination environment of the metal in a single-atom catalytic system may influence the catalytic performance remains limited. In this work, high- and low-coordinating Ru-based (RuHC and RuLC) catalysts with distinct Ru-O coordination numbers are prepared using one-pot and two-step methods. The difference in the stability (12.3% and negligible deactivation during 20 h test for RuLC and RuHC catalysts respectively) and selectivity (0.57 and 0.37 of H2/CO ratio) brought by the coordination environment signified the structure-function relationship of single-atom catalysts in DRM. The impact of the structure on the properties is systematically investigated by thorough structural and operando characterization as well as density functional theory (DFT) calculation. The findings contribute to the optimal design of single-atom catalysts for DRM, offering a theoretical basis for industrial catalyst development and the potential to improve the process's environmental impact.