Ru Single Atoms Research Articles

Ru Single Atom Dispersed on MoS2/MXene for Enhanced Sulfur Reduction Reaction in Lithium-Sulfur Batteries.

The high theoretical energy density (2600 Whkg-1) and low cost of lithium-sulfur batteries (LSBs) make them an ideal alternative for the next-generation energy storage system. Nevertheless, severe capacity degradation and low sulfur utilization resulting from shuttle effect hinder their commercialization. Herein, Single-atom Ru-doped 1T/2H MoS2 with enriched defects decorates V2C MXene (Ru-MoS2/MXene) produced by a new phase-engineering strategy employed as sulfur host to promote polysulfide adsorption and conversion reaction kinetics. The Ru single atom-doped adjusts the chemical environment of the MoS2/MXene to anchor polysulfide and acts as an efficient center to motivate the redox reaction. In addition, the rich defects of the MoS2 and ternary boundary among 1T/2H MoS2 and V2C accelerate the charge transfer and ion movements for the reaction. As expected, the Ru-MoS2/MXene/S cathode-based cell exhibits a high-rate capability of 684.3 mAh g-1 at 6 C. After 1000 cycles, the Ru-MoS2/MXene/S cell maintains an excellent cycling stability of 696 mAh g-1 at 2 C with a capacity degradation as low as 0.02% per cycle. Despite a high sulfur loading of 9.5mg cm-2 and a lean electrolyte-to-sulfur ratio of 4.3, the cell achieves a high discharge capacity of 726 mAh g-1.

Dual-type atomic Ru promoted bifunctional catalytic process realizing ultralow overpotential for Li-O2 batteries

Developing well-defined catalysts to ameliorate overpotential and cycling capability is imperative for high-performance Li-O2 batteries. However, conventional catalysts face fundamental challenges that ORR and OER with different rate-determining steps are catalyzed by the same active center, inevitably weakening the selectivity and activity. Herein, we report a cross-scale catalyst with ultrafine RuPt nanoparticles and surrounding RuPt pairs on porous carbon (RuPt NPs@RuPt-N-C). The planted Ru single atoms within Pt nanoparticles and carbon matrix contribute to a fresh bifunctional catalytic mechanism for enhancing ORR/OER catalytic kinetics. As a proof-of-concept application in Li-O2 batteries, this catalyst realizes extremely low overpotentials of only 0.43 V and superior cyclic stability of 209 cycles at 200 mA g−1. Experimental and computational results disclose that for Pt NPs@Pt-N-C without Ru functionalization, only Pt-N-C works as ORR/OER active centers. By contrast, for RuPt NPs@RuPt-N-C, due to downshifted d-band center and enhanced charge transfer with LiO2 intermediate, the Pt nanocrystals are fully activated by Ru atoms, making RuPt nanocrystals as preferable ORR kinetics promoter for the formation of easily-decomposed nanoflower Li2O2. Moreover, adjacent RuPt pairs with weakened O2 affinity can work as major OER center, contributing to accelerating the following Li2O2 decomposition. This work expands the frontier of cross-scale electrocatalysts with tailored bifunctional catalysis properties for other electrocatalytic fields.

Theoretical Study of Single-Atom Catalysts for Hydrogen Evolution Reaction Based on BiTeBr Monolayer.

Developing an inexpensive and efficient catalyst for a hydrogen evolution reaction (HER) is an effective measure to alleviate the energy crisis. Single-atom catalysts (SACs) based on Janus materials demonstrated promising prospects for the HER. Herein, density functional theory calculations were conducted to systematically investigate the performance of SACs based on the BiTeBr monolayer. Among the one hundred and forty models that were constructed, fourteen SACs with potential HER activity were selected. Significantly, the SAC, in which a single Ru atom is anchored on a BiTeBr monolayer with a Bi vacancy (RuS2/VBi-BiTeBr), exhibits excellent HER activity with an ultra-low |ΔGH*| value. A further investigation revealed that RuS2/VBi-BiTeBr tends to react through the Volmer-Heyrovsky mechanism. An electronic structure analysis provided deeper insights into this phenomenon. This is because the Tafel pathway requires overcoming steric hindrance and disrupting stable electron filling states, making it challenging to proceed. This study finally employed constant potential calculations, which approximate experimental situations. The results indicated that the ΔGH* value at pH = 0 is 0.056 eV for RuS2/VBi-BiTeBr, validating the rationality of the traditional Computational Hydrogen Electrode (CHE) method for performance evaluation in this system. This work provides a reference for the research of new HER catalysts.

Efficient catalytic degradation of carbamazepine using single-atom Ru-NiFe-LDH: Role of 1O2 and selective degradation

The targeted elimination of stubborn organic pollutants is crucial for human health and ecosystem well-being. Thanks to its exceptional efficiency and other benefits, peroxymonosulfate offers extensive potential for water treatment. However, realizing the practical application of this technology hinges on creating a high-efficiency catalyst. This study presents the fabrication of a monoatomic Ru catalyst through a straightforward hydrothermal approach. Synchrotron radiation and spherical electron microscopy were used to confirm the binding of monoatomic Ru to the NiFe-LDH (Layered Double Hydroxide, LDH) surface. Using a catalyst containing 0.77 wt% of single-atom Ru, 20 mg/L of Carbamazepine (CBZ) could be eliminated within 25 mins. With this, an impressive pseudo-first-order reaction rate constant of 0.118 min−1 was attained. The feasibility of the catalyst was evaluated in a column experimental reactor. The removal rate of 0.5 g of catalyst in wastewater containing 20 mg/L CBZ reached 100 %, demonstrating sustained operation for 720 mins. Ru-LDH/PMS system preferentially degrades carbamazepine, ciprofloxacin and other pollutants. This may be related to the structure and HOMO value of the pollutants and the active factors stimulated by Ru-LDH. Through a range of probe reactions and spectral analysis, it was determined that 1O2 played a pivotal role in pollutant degradation, closely linked to the presence of Ru.

Development of single-atom Ru and N, S-Co-doped carbon catalyst for enhanced cycling stability of lithium-oxygen batteries

Li-oxygen (Li-O2) battery is a novel energy storage equipment. However, its poor reaction reversibility relating to the insoluble lithium peroxide (Li2O2) generated during the discharge process, limits its application and development for large scale use. Therefore, the design and synthesis of effective catalysts which can efficiently catalyze the production and decomposition of Li2O2 and exclude the generation of side-products has become the primary task to develop Li-O2 batteries. Herein, a new type of electrocatalyst based on single-atom Ru and N, S-co-doped carbon materials (Ru/CNS/CNT) is introduced to reduce the overpotential of the battery reaction and accelerate the formation and decomposition of Li2O2. Galvanostatic charge-discharge tests were performed on the Li-oxygen (Li-O2) battery with Ru/CNS/CNT as the cathode catalyst material. With a limited specific capacity of 1000 mA h g−1, the battery can stably cycle for 79 cycles at a current density of 200 mA g−1. Furthermore, the existence of the single atom of Ru was demonstrated according to the characterization of HAADF-STEM. The experimental results showed that composite material Ru/CNS/CNT can accelerate the formation and decomposition of lithium peroxide (Li2O2), thereby greatly improving the cycling stability of the battery.

Tailoring the d-band center on Ru1Cu single-atom alloy nanotubes for boosting electrochemical non-enzymatic glucose sensing.

The development of cost-effective and highly efficient electrocatalysts is critical to help electrochemical non-enzymatic sensors achieve high performance. Here, a new class of catalyst, Ru single atoms confined on Cu nanotubes as asingle-atom alloy (Ru1Cu NTs), with aunique electronic structure and property, was developed to construct a novel electrochemical non-enzymatic glucose sensor for the first time. The Ru1Cu NTs with a diameter of about 24.0nm showed amuch lower oxidation potential (0.38V) and 9.0-fold higher response (66.5 μA) current than Cu nanowires (Cu NWs, oxidation potential 0.47V and current 7.4 μA) for glucose electrocatalysis. Moreover, as an electrochemical non-enzymatic glucose sensor, Ru1Cu NTs not only exhibited twofold higher sensitivity (54.9 μA mM-1cm-2) and wider linear range (0.5-8mM) than Cu NWs, but also showed alow detection limit (5.0μM), excellent selectivity, and great stability. According to theoretical calculation results, the outstanding catalytic and sensing performance of Ru1Cu NTs could be ascribed to the upshift of the d-band center that helped promote glucose adsorption. This work presents a new avenue for developing highly active catalysts for electrochemical non-enzymatic sensors.

Boosting Electrocatalytic Ethylene Epoxidation by Single Atom Modulation.

The electrochemical synthesis of ethylene oxide (EO) using ethylene and water under ambient conditions presents a low-carbon alternative to existing industrial production process. Yet, the electrocatalytic ethylene epoxidation route is currently hindered by largely insufficient activity, EO selectivity, and long-term stability. Here we report a single atom Ru-doped hollandite structure KIr4O8 (KIrRuO) nanowire catalyst for efficient EO production via a chloride-mediated ethylene epoxidation process. The KIrRuO catalyst exhibits an EO partial current density up to 0.7 A cm-2 and an EO yield as high as 92.0 %. The impressive electrocatalytic performance towards ethylene epoxidation is ascribed to the modulation of electronic structures of adjacent Ir sites by single Ru atoms, which stabilizes the *CH2CH2OH intermediate and facilitates the formation of active Cl2 species during the generation of 2-chloroethanol, the precursor of EO. This work provides a single atom modulation strategy for improving the reactivity of adjacent metal sites in heterogeneous electrocatalysts.

Boosting Electrocatalytic Ethylene Epoxidation by Single Atom Modulation

AbstractThe electrochemical synthesis of ethylene oxide (EO) using ethylene and water under ambient conditions presents a low‐carbon alternative to existing industrial production process. Yet, the electrocatalytic ethylene epoxidation route is currently hindered by largely insufficient activity, EO selectivity, and long‐term stability. Here we report a single atom Ru‐doped hollandite structure KIr4O8 (KIrRuO) nanowire catalyst for efficient EO production via a chloride‐mediated ethylene epoxidation process. The KIrRuO catalyst exhibits an EO partial current density up to 0.7 A cm−2 and an EO yield as high as 92.0 %. The impressive electrocatalytic performance towards ethylene epoxidation is ascribed to the modulation of electronic structures of adjacent Ir sites by single Ru atoms, which stabilizes the *CH2CH2OH intermediate and facilitates the formation of active Cl2 species during the generation of 2‐chloroethanol, the precursor of EO. This work provides a single atom modulation strategy for improving the reactivity of adjacent metal sites in heterogeneous electrocatalysts.

Interfacial Metal-Support Interaction and Catalytic Performance of Perovskite LaCrO3-Supported Ru Catalyst.

Interfacial metal-support interaction (MSI) significantly affects the dispersion of active metals on the surface of the catalyst support and impacts catalyst performance. Understanding MSI is crucial for developing highly active and stable catalysts with a low metal loading, particularly for noble metal catalysts. In this work, we synthesized LaRuxCr1-xO3 catalysts with low Ru loading (x = 0.005, 0.01, and 0.02) using the sol-gel self-combustion method. We found that all of the Ru atoms immediately above or below the metal-support interface are closely bonded to the perovskite LaCrO3 surface lattice through Ru-O bonds, enhancing the MSI via interfacial reaction and charge transfer mechanisms. We identified a variety of Ru species, including small 3D Ru nanoparticles, 2D dispersed Ru surface atoms, and even 0D Ru single atoms. These highly dispersed Ru species exhibit high activity and stability under dry reforming of methane (DRM) conditions. The LaRu0.01Cr0.99O3 catalyst with very low Ru loading (0.42 wt %) was stable over a 50 h DRM test and the carbon deposition was negligible. The CH4 and CO2 conversions at 750 °C reached 83 and 86%, respectively, approaching the theoretical thermodynamic equilibrium values.

Ultrahigh Bifunctional Photocatalytic CO2 Reduction and H2 Evolution by Synergistic Interaction of Heteroatomic Pt-Ru Dimerization Sites.

Diatomic-site catalysts (DASCs) inherit the excellent performance of single-atom catalysts (SACs) by utilizing two adjacent atomic metal species to achieve functional complementarity and synergistic effects that improve the carbon dioxide reduction reaction (CO2RR) and H2 evolution reaction (HER) kinetics. Herein, we report a method to further improve the catalytic efficiency of Pt by using Pt and Ru single atoms randomly anchored on a g-C3N4 surface, yielding partial Pt-Ru dimers. The synthesized catalyst exhibits extraordinary photocatalytic activity and stability in both the CO2RR and HER processes. In-depth experimentation, the pH-dependent chemical exchange saturation transfer (CEST) imaging nuclear magnetic resonance (NMR) method, and theoretical analyses reveal that the excellent performance is attributed to orbital coupling between the Pt atoms and the neighboring Ru atoms (mainly dxy and dxz), which decreases the orbital energy levels and weakens the bond strength with intermediates, resulting in improved CO2RR and HER performance. This study successfully applies the pH-dependent CEST imaging NMR method to catalytic reactions, and CO2 adsorption is directly observed using CEST 2D imaging maps. This work presents significant potential for a variety of catalytic reaction applications by systematically designing bimetallic dimers with higher activity and stability.

Ice-Templated Synthesis of Atomic Cluster Cocatalyst with Regulable Coordination Number for Enhanced Photocatalytic Hydrogen Evolution.

Supported metal catalysts have been exploited in various applications. Among them, cocatalyst supported on photocatalyst is essential for activation of photocatalysis. However, cocatalyst decoration in a controllable fashion to promote intrinsic activity remains challenging. Herein, a versatile method is developed for cocatalyst synthesis using an ice-templating (ICT) strategy, resulting in size control from single-atom (SA), and atomic clusters (AC) to nanoparticles (NP). Importantly, the coordination numbers (CN) of decorated AC cocatalysts are highly controllable, and this ICT method applies to various metals and photocatalytic substrates. Taking narrow-band gap Ga-doped La5Ti2Cu0.9Ag0.1O7S5 (LTCA) photocatalyst as an example, supported Ru AC/LTCA catalysts with regulable Ru CNs have been prepared, delivering significantly enhanced activities compared to Ru SA and Ru NPs supported on LTCA. Specifically, Ru(CN = 3.4) AC/LTCA with an average CN of Ru─Ru bond measured to be ≈3.4 exhibits excellent photocatalytic H2 evolution rate (578µmol h-1) under visible light irradiation. Density functional theory calculation reveals that the modeled Ru(CN = 3) atomic cluster cocatalyst possesses favorable electronic properties and available active sites for the H2 evolution reaction.

Dual efficiency enhancement in overall water splitting with defect-rich and Ru atom-doped NiFe LDH nanosheets on NiCo2O4 nanowires

The development of layered double hydroxides (LDHs) as bifunctional catalysts for efficient overall water splitting by controlling the composition and structure of the material remains challenging. In this study, defect-rich and Ru-doped NiFe LDH nanosheet shells on NiCo2O4 (NCO) nanowires were successfully synthesized using a hydrothermal method, followed by alkaline etching. The resulting def-Ru-NiFe LDH/NCO (def = defects) catalyst exhibited remarkable catalytic activity with overpotentials of 122 and 225 mV for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively, at a current density of 10 mA cm−2. Density functional theory calculations demonstrated that atomic vacancy defects and the rational incorporation of Ru single atoms in def-Ru-NiFe LDH/NCO induced the regulation of the electronic structure and optimized the adsorption energies, thus enhancing the OER and HER performances. Particularly, an electrolyzer utilizing def-Ru-NiFe LDH/NCO exhibited exceptional performance, achieving cell voltages of 1.58 and 1.46 V in 1 M KOH at 25 and 75 °C, respectively. Moreover, the catalyst exhibited outstanding stability during 60 h of operation at a high applied voltage and temperature (75 °C). These results highlight the potential of def-Ru-NiFe LDH/NCO for hydrogen production.

Symmetry-Broken Ru Nanoparticles with Parasitic Ru-Co Dual-Single Atoms Overcome the Volmer Step of Alkaline Hydrogen Oxidation.

Efficient dual-single-atom catalysts are crucial for enhancing atomic efficiency and promoting the commercialization of fuel cells, but addressing the sluggish kinetics of hydrogen oxidation reaction (HOR) in alkaline media and the facile dual-single-atom site generation remains formidable challenges. Here, we break the local symmetry of ultra-small ruthenium (Ru) nanoparticles by embedding cobalt (Co) single atoms, which results in the release of Ru single atoms from Ru nanoparticles on reduced graphene oxide (Co1 Ru1,n /rGO). In situ operando spectroscopy and theoretical calculations reveal that the oxygen-affine Co atom disrupts the symmetry of ultra-small Ru nanoparticles, resulting in parasitic Ru and Co dual-single-atom within Ru nanoparticles. The interaction between Ru single atoms and nanoparticles forms effective active centers. The parasitism of Co atoms modulates the adsorption of OH intermediates on Ru active sites, accelerating HOR kinetics through faster formation of *H2 O. As anticipated, Co1 Ru1,n /rGO exhibits ultrahigh mass activity (7.68 A mgRu -1 ) at 50 mV and exchange current density (0.68 mA cm-2 ), which are 6 and 7 times higher than those of Ru/rGO, respectively. Notably, it also displays exceptional durability surpassing that of commercial Pt catalysts. This investigation provides valuable insights into hybrid multi-single-atom and metal nanoparticle catalysis.

Symmetry‐Broken Ru Nanoparticles with Parasitic Ru‐Co Dual‐Single Atoms Overcome the Volmer Step of Alkaline Hydrogen Oxidation

AbstractEfficient dual‐single‐atom catalysts are crucial for enhancing atomic efficiency and promoting the commercialization of fuel cells, but addressing the sluggish kinetics of hydrogen oxidation reaction (HOR) in alkaline media and the facile dual‐single‐atom site generation remains formidable challenges. Here, we break the local symmetry of ultra‐small ruthenium (Ru) nanoparticles by embedding cobalt (Co) single atoms, which results in the release of Ru single atoms from Ru nanoparticles on reduced graphene oxide (Co1Ru1,n/rGO). In situ operando spectroscopy and theoretical calculations reveal that the oxygen‐affine Co atom disrupts the symmetry of ultra‐small Ru nanoparticles, resulting in parasitic Ru and Co dual‐single‐atom within Ru nanoparticles. The interaction between Ru single atoms and nanoparticles forms effective active centers. The parasitism of Co atoms modulates the adsorption of OH intermediates on Ru active sites, accelerating HOR kinetics through faster formation of *H2O. As anticipated, Co1Ru1,n/rGO exhibits ultrahigh mass activity (7.68 A mgRu−1) at 50 mV and exchange current density (0.68 mA cm−2), which are 6 and 7 times higher than those of Ru/rGO, respectively. Notably, it also displays exceptional durability surpassing that of commercial Pt catalysts. This investigation provides valuable insights into hybrid multi‐single‐atom and metal nanoparticle catalysis.

Construction of Ru Single-Atoms on Ceria to Reform the Products of CO2 Photoreduction.

Highly selective production of CH4 from photocatalytic CO2 reduction is still a great challenge which involves the kinetically unfavorable transfers of 8 protons and 8 electrons. Herein, CeO2 photocatalysts incorporated with isolated Ru single-atoms have been fabricated, which demonstrate dramatically elevated selectivity of CH4 from CO2 reduction. The introduced Ru single-atoms promote carrier separation and accelerate electron transfer, which efficiently enhances the photocatalytic activity. Density functional theory (DFT) calculations and in situ FT-IR analysis manifest that the Ru single-atom active sites play an indispensable role in strengthening the adsorption of *CO intermediate on the catalyst surface and promoting H2O oxidation to generate abundant protons, thus favoring *CO protonation into *CHxO (x = 1, 2, 3) species and final deoxygenation into CH4. This work provides an effective strategy by constructing single-atom active sites to modulate and stabilize the key intermediates of CO2 photoreduction to improve the selectivity of the target products.

Recent Progress of Ru Single‐Atom Catalyst: Synthesis, Modification, and Energetic Applications

AbstractIn 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.

Alleviating OH Blockage on the Catalyst Surface by the Puncture Effect of Single-Atom Sites to Boost Alkaline Water Electrolysis.

Nonprecious transition metal catalysts have emerged as the preferred choice for industrial alkaline water electrolysis due to their cost-effectiveness. However, their overstrong binding energy to adsorbed OH often results in the blockage of active sites, particularly in the cathodic hydrogen evolution reaction. Herein, we found that single-atom sites exhibit a puncture effect to effectively alleviate OH blockades, thereby significantly enhancing the alkaline hydrogen evolution reaction (HER) performance. Typically, after anchoring single Ru atoms onto tungsten carbides, the overpotential at 10 mA·cm-2 is reduced by more than 130 mV (159 vs 21 mV). Also, the mass activity is increased 16-fold over commercial Pt/C (MA100 = 17.3 A·mgRu-1 vs 1.1 A·mgPt-1, Pt/C). More importantly, such electrocatalyst-based alkaline anion-exchange membrane water electrolyzers can exhibit an ultralow potential (1.79 Vcell) and high stability at an industrial current density of 1.0 A·cm-2. Density functional theory (DFT) calculations reveal that the isolated Ru sites could weaken the surrounding local OH binding energy, thus puncturing OH blockage and constructing bifunctional interfaces between Ru atoms and the support to accelerate water dissociation. Our findings exhibit generality to other transition metal catalysts (such as Mo) and contribute to the advancement of industrial-scale alkaline water electrolysis.

Single Atom Ru Doped Ni2P/Fe3P Heterostructure for Boosting Hydrogen Evolution for Water Splitting.

Modulating the chemical composition and structure has been considered as one of the most promising strategies for developing high-efficient water splitting catalysts. Here, a single-atom Ru doped Ni2P/Fe3P catalyst is synthesized by introducing the dispersed Ru atoms to adjust Ni2P/Fe3P heterostructure. Single atom Ru provides effective hydrogen evolution reaction (HER) active sites for boosting catalytic activities. The catalyst with only 0.2wt.% content of Ru exhibits an overpotential of 19.3mV at 10mA cm-2, which is obviously lower than 146.1mV of Ni2P/Fe3P. Notably, an alkaline overall water electrolyzer based on Ru-Ni2P/Fe3P catalysts achieves a cell voltage of 1.47V and operates over 600h at 10mA cm-2, which is superior to that of benchmark RuO2//Pt/C (1.61V). The theoretical calculations further confirm that Ru single atom doping can effectively optimize the hydrogen/water adsorption free energy of the active site and therefore improve the HER activity of heterostructure. This work provides a valuable reference to design high-activity and durability catalyst for water splitting through the double modulation of interface-effect and atomic doping.

Unveiling the Morphology of Carbon-Supported Ru Nanoparticles by Multiscale Modeling.

Simulating the behavior of metal nanoparticles on supports is crucial for boosting their catalytic performance and various nanotechnology applications; however, such simulations are limited by the conflicts between accuracy and efficiency. Herein, we introduce a multiscale modeling strategy to unveil the morphology of Ru supported on pristine and N-doped graphene. Our multiscale modeling started with the electronic structures of a supported Ru single atom, revealing the strong metal-support interaction around pyridinic nitrogen sites. To determine the stable configurations of Ru2-13 clusters on three different graphene supports, global energy minimum searches were performed. The sintering of the global minimum Ru13 clusters on supports was further simulated by ab initio molecular dynamics (AIMD). The AIMD data set was then collected for deep potential molecular dynamics to study the melting of Ru nanoparticles. This study presents comprehensive descriptions of carbon-supported Ru and develops modeling approaches that bridge different scales and can be applied to various supported nanoparticle systems.

Efficient CO2 capture and in-situ electrocatalytic conversion on MgO surface by metal single-atom engineering: A comprehensive DFT study

CO2 capture and electrochemical CO2 conversion are both extremely energy-intensive processes, and synergistic coupling between the two processes can increase the ecological sustainability of the system and decrease the cost of the generated products. Here, we investigated the enhancement of CO2 capture performance on MgO (100) surface by thirteen types of metal single-atom engineering using density functional theory (DFT) method. The doping of Pt, Ru, or Rh single atom transforms the adsorption of CO2 on the surface of MgO (100) from physical to chemical processes. The MgO surface doped with Ru single atom has the maximum CO2 adsorption energy of −1.46 eV. Notably, this chemical interaction with the surface activates inactive O = C = O bond of CO2 significantly, which is advantageous for the generation of the intermediate *COOH during the electrochemical conversion process. Reaction pathway analysis shows that Ru@MgO surface exhibits high activity and selectivity for the electrochemical conversion of CO2 to CH4. DFT results show that Ru@MgO can be used to separate CO2 from flue gas and electro-catalyze CO2 into CH4 in-situ efficiently, paving the way for the development of a novel CO2 separation technology with low energy consumption and high efficiency.