Ru Nanoclusters Research Articles

Plasmonic Copper‐Ruthenium Superstructure for Efficient Photothermal Conversion and Plastic Recycling

AbstractPlasmonic superstructures offer broad prospects in photothermal catalysis, yet their controllable synthesis remains a challenge. Here, a controlled synthesis method for Cu‐Ru plasmonic superstructures via a one‐step polyol reduction process is presented, where Cu nanoparticles serve as the core, while the shell is formed from Ru nanoclusters. Through a comprehensive investigation of the growth mechanism, precise control over the composition and size of the superstructures is achieved. Finite‐difference time‐domain simulations and photothermal conversion experiments demonstrated that the optimized Cu3Ru1 superstructures possess strong light absorption capabilities and efficient photothermal conversion performance. These properties are effectively utilized in the photothermal recycling of waste polyethylene and polyethylene terephthalate, marking a significant advance in employing Cu‐based plasmonic materials for sustainable catalytic technology.

Modulating Nitrogen Adsorption Mode and Microenvironment of Active Sites for Boosting Electrochemical Nitrogen Reduction.

Electrochemical reduction of N2(NRR) offers a sustainable approach for ammonia (NH3) synthesis, serving as a complementary to the traditional emission- and energy-intensive Haber-Bosch process. However, it faces challenges in N2 activation and competing with pronounced hydrogen evolution reaction (HER). Herein an efficient electrocatalyst comprised of ultrafine Ru nanoclusters (NCs) confined by a hydrophobic molecular layer is developed on the surface of 2D Ti3C2Tx for NRR. These experimental and theoretical calculation results demonstrate that 1) ultrafine Ru NCs dispersed on the Ti3C2Tx surface form paired active sites for N2 chemisorption in a unique tilted configuration with low-energy activation 2) the hydrophobic molecular layer modulates the local microenvironment surrounding catalytically active sites, enabling efficient N2 accumulation while repelling H2O diffusion to the active sites on the Ti3C2Tx surface, thereby leading to an increased N2 concentration and suppressed HER. As a result, an exceptionally high NH3 yield rate of 33.5µg h-1mg-1cat and Faradaic efficiency of 65.3% are obtained at -0.25V versus reversible hydrogen electrode (RHE) in 0.1m Na2SO4, outperforming those previously reported Ti3C2Tx-derived electrocatalysts. This work provides a valuable strategy for the rational design of advanced electrocatalysts by manipulating active sites and local microenvironments for efficient electrocatalysis.

Constructing of n‐Type Semiconductor Heterostructures for Efficient Hydrazine‐Assisted Hydrogen Production

AbstractHydrazine‐assisted water electrolysis presents a promising approach toward energy‐efficient hydrogen production. However, the progress of this technology is hindered by the limited availability of affordable, efficient, and durable catalysts. In this study, a feasible strategy is proposed for interface modulation that enables efficient hydrogen evolution and hydrazine oxidation through the construction of n‐type semiconductor heterostructures. The metal–semiconductor contacts are rationally designed using ruthenium nanoclusters and a range of metal oxide (M–O) semiconductor heterostructures, including p‐type semiconductor substrates (NiO, Co3O4, NiCo2O4, CuCo2O4, ZnCo2O4) and n‐type semiconductor substrate (Fe2O3). Intriguingly, Ru nanoclusters supported on p‐type M–O substrates induce a transition from p‐type M–O to n‐type M‐O/Ru. The design of n‐type semiconductor heterostructures can significantly reduce space‐charge regions and increase charge carrier concentration, thereby improving the electrical conductivity of electrocatalysts. Moreover, Ru atoms can serve as highly efficient active sites for hydrogen evolution reaction and hydrazine oxidation reaction. The NiO/Ru heterostructure can drive current densities of 10 and 100 mA cm−2 with only 0.021 and 0.22 V cell voltages for hydrazine‐assisted water electrolysis. This work provides new insights for the development of highly efficient semiconductor catalysts, enabling energy‐saving hydrogen production.

Anchored Ru nanoclusters strategy enhances hydrogen spillover effect for high-efficiency hydrogen storage

Enhancing the hydrogen spillover effect of catalysts is an effective method for optimizing hydrogen storage reactions. In this study, we report a catalyst consisting of Ru nanoclusters (1.2–2.7 nm) anchored on nitrogen-doped carbon (NC) that are highly dispersed on an Al2O3 substrate. Both experimental and density functional theory-based calculations indicate that these constrained, highly dispersed ultrafine nanoclusters significantly improve the intrinsic catalytic activity of Ru and reduce the reaction barriers. Moreover, the electron transfer between NC and Ru clusters increases the adsorption inertness of Ru with hydrogen, enhances hydrogen desorption, and promotes hydrogen spillover, synergistically improving the activity of catalytic hydrogen storage. Notably, the aromatic compounds in the ethylene tar narrow fraction were effectively converted at a low temperature of 80 °C, and the total cycloalkanes yield reached 99.04 %. The hydrogen storage capacity can be about 5.70 wt%. Liquid Organic Hydrogen Carriers model compounds were fully hydrogenated at temperatures no higher than 70 °C with low Ru loading (2 wt%). This work provides a potential utilization strategy of ethylene tar narrow fraction as hydrogen carriers based on its hydrogenation over the highly active and stable Ru nanocluster catalysts.

Assembly of low-voltage driven co-production of hydrogen and sulfur via Ru nanoclusters on metal-sulfur coordination: Insights from DFT calculations

Herein, we propose a simple and rapid approach for synthesizing a CuS/Ru composite that serves as a bifunctional electrocatalyst to promote hydrogen production and concurrently convert sulfion into a value-added sulfur product. This composite comprises Ru nanoclusters supported on the CuS nanostructure, achieved through simple pulsed laser irradiation in liquid approach. The optimized CuS/Ru-30 electrocatalyst demonstrates remarkable bifunctional electrocatalytic activity, exhibiting a negligible working potential of 0.28 V (vs. RHE) for the anodic sulfion oxidation reaction (SOR) and a minimal overpotential of 182 mV for cathodic hydrogen evolution reaction (HER) to achieve 10 mA cm−2 of current density. Moreover, the CuS/Ru-30 electrocatalyst shows exceptional selectivity for converting sulfion into valuable sulfur during anodic oxidation reactions. Remarkably, in a two-electrode electrolyzer system utilizing CuS/Ru-30 as both the anode and cathode, the SOR + HER coupled water electrolysis system demands only 0.52 V to reach 10 mA cm−2, which is considerably lesser compared to the OER + HER coupled water electrolysis (1.85 V). The experimental results and density function theory (DFT) calculations reveal that the strong electron interaction between CuS and Ru nanoclusters generates a built-in electric field, greatly enhancing electron transfer efficiency. This significantly boosts the HER performance and facilitates the adsorption and production of sulfur intermediates. This study presents a rapid and simple strategy for synthesizing a dual-functional catalyst suitable for low-voltage hydrogen generation while facilitating the recovery of valuable sulfur sources.

Exsolved Ru-mediated stabilization of MoO2-Ni4Mo electrocatalysts for anion exchange membrane water electrolysis and unbiased solar-driven saline water splitting

Molybdenum-based electrocatalysts remain the exclusive and practical option for anion exchange membrane water electrolysis (AEMWE) due to their exceptional catalytic activity in the alkaline hydrogen evolution reaction (HER). However, they are limited by low electrochemical stability resulting from the dissolution into MoO42- ions in alkaline conditions, leading to secondary phase precipitation that hinders the surface reaction. Here, we demonstrate Ru-mediated electrochemical stabilization of MoO2-Ni4Mo electrocatalysts, which exhibit exceptionally enhanced durability as well as catalytic activity, enabling ampere-level current density water splitting in saline water. Theoretical calculations and ex-situ X-ray absorption spectroscopy reveal that exsolved Ru nanoclusters with a higher hydroxyl affinity significantly establish a local hydroxide-deficient environment, leading to the stabilization of MoO2. Consequently, Ru-MoO2-Ni4Mo exhibits outstanding hydrogen production with stable operation for over 300 h to achieve a current density of 1.0 A cm−2 and a record-high solar-to-hydrogen efficiency of 22.5 % in AEMWE and photovoltaic-assisted water splitting system, respectively.

Semi-Ionic F Modified N-Doped Porous Carbon Implanted with Ruthenium Nanoclusters towardHighlyEfficient pH-Universal Hydrogen Generation.

Developing high electroactivity ruthenium (Ru)-based electrocatalysts for pH-universal hydrogen evolution reaction (HER) is challenging due to the strong bonding strengths of key Ru─H/Ru─OH intermediates and sluggish water dissociation rates on active Ru sites. Herein, a semi-ionic F-modified N-doped porous carbon implanted with ruthenium nanoclusters (Ru/FNPC) is introduced by a hydrogel sealing-pyrolying-etching strategy toward highly efficient pH-universal hydrogen generation. Benefiting from the synergistic effects between Ru nanoclusters (Ru NCs) and hierarchically F, N-codoped porous carbon support, such synthesized catalyst displays exceptional HER reactivity and durability at all pH levels. The optimal 8Ru/FNPC affords ultralow overpotentials of 17.8, 71.2, and 53.8mV at the current density of 10mA cm-2 in alkaline, neutral, and acidic media, respectively. Density functional theory (DFT) calculations elucidate that the F-doped substrate to support Ru NCs weakens the adsorption energies of H and OH on Ru sites and reduces the energy barriers of elementary steps for HER, thus enhancing the intrinsic activity of Ru sites and accelerating the HER kinetics. This work provides new perspectives for the design of advanced electrocatalysts by porous carbon substrate implanted with ultrafine metal NCs for energy conversion applications.

Synergistic coupling of defective Ru nanoclusters with oxygen-ligand-steered Ru single-atoms modifying interfacial water structure and key intermediates bonding toward efficient hydrogen energy conversion

Constructing highly efficient ruthenium (Ru)-based electrocatalysts and understanding their reaction mechanisms for hydrogen energy conversion are highly desirable, but extremely challenge. Herein, we integrate the well-dispersed defective Ru nanoclusters and oxygen-coordinated Ru single atoms into one electrocatalyst (RuSA-O4/RuNC) toward alkaline hydrogen oxidation and evolution reactions (HOR/HER). Synergistic catalytic mechanism of dual-sites has been revealed by in situ ATR-SEIRAS characterization, EDTA/SCN– poisoning experiments and DFT calculations. Benefiting from the electronic redistribution between RuSA-O4 and RuNC sites, the single-atom RuSA-O4 species can act as Lewis acid sites that display strong affinity toward interfacial water via an O-down (H2O↓) conformation and subsequently promote water dissociation/formation as well as hydroxide adsorption. Meanwhile, adjacent defective Ru sites have around thermoneutral value of H adsorption free energy. RuNC works with RuSA-O4 species, collaboratively reducing reaction barriers. As expected, the RuSA-O4/RuNC achieves 20.3 times mass activity of commercial Pt/C for alkaline HOR at 10 mV overpotential and excellent alkaline HER activity with a low overpotential of 22 mV to deliver 10 mA cm−2, as well as considerable HER mass activity of 17.0-times compared to commercial Pt/C at 50 mV overpotential. Besides, the synergistic dual-sites strategy can also be extended to prepare efficient PtSA-O4/PtNC and IrSA-O4/IrNC electrocatalysts.

Carbon/ruthenium hybrid nanozymes for efficient β-glucosidase sensing

Highly efficient nanozymes are useful for constructing sensors with exceptional performance. Herein, carbon nanotubes loaded with ruthenium nanoclusters (Ru/CNTs) were successfully prepared through a straightforward ambient chelating reduction synthetic method. The strong d-π interactions between CNTs and metallic Ru facilitated the nucleation, dispersion, and enduring stability of Ru nanoclusters. Benefiting from the robust peroxidase-like activity and recyclability of Ru/CNTs, an accurate colorimetric sensing platform was established for efficient β-glucosidase (BG) sensing. Ru/CNTs efficiently catalyzed H2O2 to generate reactive oxygen species (ROS, O2•− and 1O2), initiating the chromogenic reaction of 3,3′,5,5′-tetramethylbenzidine (TMB). However, the above chromogenic reaction was suppressed in the presence of HQ due to its inherent reducibility. Using phenolic β-arbutin (BA) as substrate, BG catalyzed the hydrolysis of BA, releasing HQ. The proposed Ru/CNTs-based sensing system, involving the implementation of two-step catalytic reactions and concurrently possessing the stability and high specificity of enzymes, significantly enhanced the system’s selectivity and sensitivity. As expected, this colorimetric sensor exhibited remarkable sensitivity (limit of detection, LOD 0.472 U L−1) with exceptional accuracy (recoveries, 94.84–111.32 %; RSD, 0.89–3.07 %). Overall, the proposed cascade catalysis strategy significantly enhanced the stability and sensitivity of the sensor, paving the way for its practical application in the fields of food and biology.

Ruthenium Nanoclusters and Single Atoms on α-MoC/N-Doped Carbon Achieves Low-Input/Input-Free Hydrogen Evolution via Decoupled/Coupled Hydrazine Oxidation.

The hydrazine oxidation-assisted H2 evolution method promises low-input and input-free hydrogen production. However, developing high-performance catalysts for hydrazine oxidation (HzOR) and hydrogen evolution (HER) is challenging. Here, we introduce a bifunctional electrocatalyst α-MoC/N-C/RuNSA, merging ruthenium (Ru) nanoclusters (NCs) and single atoms (SA) into cubic α-MoC nanoparticles-decorated N-doped carbon (α-MoC/N-C) nanowires, through electrodeposition. The composite showcases exceptional activity for both HzOR and HER, requiring -80 mV and -9 mV respectively to reach 10 mA cm-2. Theoretical and experimental insights confirm the importance of two Ru species for bifunctionality: NCs enhance the conductivity, and its coexistence with SA balances the H ad/desorption for HER and facilitates the initial dehydrogenation during the HzOR. In the overall hydrazine splitting (OHzS) system, α-MoC/N-C/RuNSA excels as both anode and cathode materials, achieving 10 mA cm-2 at just 64 mV. The zinc hydrazine (Zn-Hz) battery assembled with α-MoC/N-C/RuNSA cathode and Zn foil anode can exhibit 97.3 % energy efficiency, as well as temporary separation of hydrogen gas during the discharge process. Therefore, integrating Zn-Hz with OHzS system enables self-powered H2 evolution, even in hydrazine sewage. Overall, the amalgamation of NCs with SA achieves diverse catalytic activities for yielding multifold hydrogen gas through advanced cell-integrated-electrolyzer system.

Ruthenium Nanoclusters and Single Atoms on α‐MoC/N‐Doped Carbon Achieves Low‐Input/Input‐Free Hydrogen Evolution via Decoupled/Coupled Hydrazine Oxidation

AbstractThe hydrazine oxidation‐assisted H2 evolution method promises low‐input and input‐free hydrogen production. However, developing high‐performance catalysts for hydrazine oxidation (HzOR) and hydrogen evolution (HER) is challenging. Here, we introduce a bifunctional electrocatalyst α‐MoC/N−C/RuNSA, merging ruthenium (Ru) nanoclusters (NCs) and single atoms (SA) into cubic α‐MoC nanoparticles‐decorated N‐doped carbon (α‐MoC/N−C) nanowires, through electrodeposition. The composite showcases exceptional activity for both HzOR and HER, requiring −80 mV and −9 mV respectively to reach 10 mA cm−2. Theoretical and experimental insights confirm the importance of two Ru species for bifunctionality: NCs enhance the conductivity, and its coexistence with SA balances the H ad/desorption for HER and facilitates the initial dehydrogenation during the HzOR. In the overall hydrazine splitting (OHzS) system, α‐MoC/N−C/RuNSA excels as both anode and cathode materials, achieving 10 mA cm−2 at just 64 mV. The zinc hydrazine (Zn−Hz) battery assembled with α‐MoC/N−C/RuNSA cathode and Zn foil anode can exhibit 97.3 % energy efficiency, as well as temporary separation of hydrogen gas during the discharge process. Therefore, integrating Zn−Hz with OHzS system enables self‐powered H2 evolution, even in hydrazine sewage. Overall, the amalgamation of NCs with SA achieves diverse catalytic activities for yielding multifold hydrogen gas through advanced cell‐integrated‐electrolyzer system.

Oxygen-vacancy-rich Ru nanoclusters doped NiCo metal-organic framework for driving overall water electrolysis and supercapacitors

Due to the growing demand for clean renewable hydrogen fuel, the rational design of electrode materials' composition and structure holds significant importance in achieving efficient energy storage and conversion in electrochemical energy devices. In this study, we synthesize NiCo-MOF74/NF substrate using a one-step hydrothermal method, after which we successfully deposit a layer of Ru metal nanoclusters on the substrate by electrodeposition. Ru NCs@NiCo-MOF74/NF exhibits an exceptionally large specific surface area and excellent interface effects, demonstrating outstanding performance in both overall water splitting and supercapacitor applications. In a 1 M KOH alkaline solution, the device requires only 1.47 V output voltage to deliver a current density of 10 mA cm−2 for overall water splitting. As a supercapacitor, the unique nanoflower structure of Ru NCs@NiCo-MOF74/NF enables fast and reversible Faradaic reactions, providing high specific capacitance and rate performance. It shows a high areal capacitance of 1.664 mAh cm−2 at 1 mA cm−2, indicating excellent charge storage capacity. Assembled into an asymmetric supercapacitor (ASC) with Ru NCs@NiCo-MOF74/NF as the positive electrode, the device achieves a high energy density of 511.88 μWh cm−2 at a power density of 545.68 μW cm−2. After 5000 cycles, the capacitance retention rate is approximately 100 %, demonstrating remarkable cycling stability. This paves the way for the synthesis of multifunctional catalysts, opening up new possibilities in the field.

Thermal Shock Synthesis for Loading Sub-2nm Ru Nanoclusters on Titanium Nitride as a Remarkable Electrocatalyst toward Hydrogen Evolution Reaction.

Heterogeneous catalysts embracing metal entities on suitable supports are profound in catalyzing various chemical reactions, and substantial synthetic endeavors in metal-support interaction modulation are made to enhance catalytic performance. Here, it is reported the loading of sub-2nm Ru nanocrystals (NCs) on titanium nitride support (HTS-Ru-NCs/TiN) via a special Ru-Ti interaction using the high-temperature shock (HTS) method. Direct dechlorination of the adsorbed RuCl3, ultrafast nucleation process, and short coalescence duration at ultrahigh temperatures contribute to the immobilization of Ru NCs on TiN support via producing the Ru-Ti interfacial perimeter. HTS-Ru-NCs/TiN shows remarkable activity toward hydrogen evolution reaction (HER) in alkaline solution, yielding ultralow overpotentials of 16.3 and 86.6mV to achieve 10 and 100mAcm-2, respectively. The alkaline and anion exchange membrane water electrolyzers assembled using HTS-Ru-NCs/TiN yield 1.0Acm-2 at 1.65 and 1.67V, respectively, which validate its applicability in the hydrogen production industry. Theoretical simulations reveal the favorable formation of Ru─O and Ti─H bonds at the interfacial perimeters between Ru NCs and TiN, which accelerates the prerequisite water dissociation kinetics for enhanced HER activity. This exemplified work motivates the design of specific interfacial perimeters via the HTS strategy to improve the performance of diverse catalysis.

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 electrodes. 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.

Coupling electron donors with proton repulsion via Pt-N3-S sites to boost CO2 reduction in CO2/H2 fuel cell

A fuel cell involving CO2/H2 is an appealing energy system to convert CO2 into synthetic fuels as well as to generate electricity using only waste heat. However, overcoming the inherent activation barrier of CO2 to improve the CO2 conversion rate in CO2/H2 fuel cell is still challenging. Herein, we report a synergistic electron-donor and proton-repulsion group composed of Pt-N3-S-C sites to simultaneously modulate the electronic structure and CO2-protonation ability of Ru nanoclusters (RuNC) in RuNC/Pt-N3-S-C catalyst. Experiments combined with theoretical calculations indicate that Pt-N3-S sites not only function as electron donors to Ru nanoclusters to cooperatively induce the orbital hybridization of Ru 3d and the antibonding orbitals of CO2, affording the dissociation of CO bonds in CO2, but also as electronic structure “modulator” to create new active sites on the surface of RuNC to effectively activate molecular CO2. More importantly, an internal polarization field between Pt-N3-S-C and RuNC additionally makes single atom Pt sites repel protons while Ru atoms serve as proton capturers via hydrogen spillover effect, resulting in accelerated protonation of CO2. Consequently, the catalyst exhibits highly improved catalytic activities for CO2 reduction with a conversion rate of 559.1 μmol gcat−1 h−1. This approach helps with fine tuning the electronic structures and catalytic CO2 protonation ability of catalysts for thermal-coupled electrocatalysis.

Engineering the Metal‐Support Interaction and Oxygen Vacancies on Ru@P‐Fe/Fe3O4 Nanorods for Synergetic Enhanced Electrocatalytic Nitrate‐to‐Ammonia Conversion

AbstractRuthenium (Ru) loaded catalysts show high activity and selectivity for ammonia (NH3) synthesis via electrochemical reduction of nitrate (NO3−), but their practical application is still restricted by their high cost and insufficient stability. Herein, a multi‐component electrocatalyst of Ru nanoclusters loaded on phosphorus‐doped/phosphate‐modified and oxygen vacancy (OV)‐rich Fe/Fe3O4 composite nanorods (Ru@P‐Fe/Fe3O4) to synergistically promote electrocatalytic NO3− reduction reaction (NO3−RR)‐to‐NH3 performance via strong metal‐support interaction (SMSI) is reported. Impressively, the best Ru@P‐Fe/Fe3O4 catalyst exhibits outstanding NO3−RR activity, selectivity, and durability in 0.1 M KNO3 + 0.5 M KOH solution, with an NH3 yield rate of 14.37 ± 0.21 mgNH3 h−1 cm−2 (1710.71 ± 25 mgNH3 h−1 mgRu−1) at −0.75 V versus reversible hydrogen electrode (vs. RHE), an NH3 Faradaic efficiency (FE) of 97.2% at −0.55 V vs. RHE, and a superior stability over 50 h, suppressing most of reported Fe‐based and Ru‐based electrocatalysts. The characterizations and theoretical calculations unveil that the SMSI between Ru nanoclusters and P‐Fe/Fe3O4 composite nanorods can promote the generation of OV, tune the electronic structure of Ru species, and stabilize Ru nanoclusters, thereby reducing the reaction energy barrier of NO3−RR‐to‐NH3, inhibiting the competitive hydrogen evolution reaction, and boosting the NH3 yield rate NH3 FE, and stability.

Interfacial Design of Ti3C2Tx MXene/Graphene Heterostructures Boosted Ru Nanoclusters with High Activity Toward Hydrogen Evolution Reaction.

The development of a cost-competitive and efficient electrocatalyst is both attractive and challenging for hydrogen production by hydrogen evolution reaction (HER). Herein, a facile glycol reduction method to construct Ru nanoclusters coupled with hierarchical exfoliated-MXene/reduced graphene oxide architectures (Ru-E-MXene/rGA) is reported. The hierarchical structure, formed by the self-assembly of graphene oxides, can effectively prohibit the self-stacking of MXene nanosheets. Meanwhile, the formation of the MXene/rGA interface can strongly trap the Ru3+ ions, resulting in the uniform distribution of Ru nanoclusters within Ru-E-MXene/rGA. The boosted catalytic activity and underlying catalytic mechanism during the HER process are proved by density functional theory. Ru-E-MXene/rGA exhibits overpotentials of 42 and 62mV at 10mAcm-2 in alkaline and acidic electrolytes, respectively. The small Tafel slope and charge transfer resistance (Rct) values elucidate its fast dynamic behavior. The cyclic voltammetry (CV) curves and chronoamperometry test confirm the high stability of Ru-E-MXene/rGA. These results demonstrate that coupling Ru nanoclusters with the MXene/rGA heterostructure represents an efficient strategy for constructing MXene-based catalysts with enhanced HER activity.

Pt single atoms coupled with Ru nanoclusters enable robust hydrogen oxidation for high-performance anion exchange membrane fuel cells

Pt single atoms coupled with Ru nanoclusters enable robust hydrogen oxidation for high-performance anion exchange membrane fuel cells

Unravelling the role of work function difference on supported Ru nanoclusters for alkaline hydrogen evolution reaction

Fine tuning the work function difference (ΔΦ) between support and Ru which in turn affects the electron distribution of Ru is an effective method for the design of high-performance alkaline hydrogen evolution reaction (HER) catalysts. However, it remains a challenge to understand the intrinsic relationship between HER activity and ΔΦ at the atomic level. Herein, taking N doped graphene supported Ru nanoclusters (Ru/CxNy) as the theoretical model, we demonstrate that the HER activity can be correlated with the variation of ΔΦ. For Ru/C50 with smaller ΔΦ, we find that the Ru atoms located at the top layer of Ru nanoclusters (Ru-t) with lower coordination numbers are the main reaction sites. For Ru/C30N20 with larger ΔΦ, the stronger charge redistributions of Ru is observed, and the electron-deficient Ru atoms closing to the interface (Ru-i) are the main reaction sites with significant improvement HER activity. Our findings demonstrate the role of ΔΦ on Ru/CxNy systems for the alkaline HER, which can provide valuable theoretical guidance for the design of high efficient HER catalysts.

Titanium Dioxide and N-Doped Carbon Hybrid Nanofiber Modulated Ru Nanoclusters for High-Efficient Hydrogen Evolution Reaction Electrocatalyst.

The designing and fabricating highly active hydrogen evolution reaction (HER) electrocatalysts that can superior to Pt/C is extremely desirable but challenging. Herein, the fabrication of Ru/TiO2/N-doped carbon (Ru/TiO2/NC) nanofiber is reported as a novel and highly active HER electrocatalyst through electrospinning and subsequent pyrolysis treatment, in which Ru nanoclusters are dispersed into TiO2/NC hybrid nanofiber. As a novel support, experimental and theoretical calculation results reveal that TiO2/NC can more effectively accelerate water dissociation as well as optimize the adsorption strength of *H than TiO2 and NC, thus leading to a significantly enhanced HER activity, which merely requires an overpotential of 18mV to reach 10mAcm-2, outperforming Pt/C in an alkaline solution. The electrolytic cell composed of Ru/TiO2/NC nanofiber and NiFe LDH/NF can generate 500 and 1000mAcm-2 at voltages of 1.631 and 1.753V, respectively. Furthermore, the electrolytic cell also exhibits remarkable durability for at least 100h at 200mAcm-2 with negligible degradation in activity. The present work affords a deep insight into the influence of support on the activity of electrocatalyst and the strategy proposed in this research can also be extended to fabricate various other types of electrocatalysts for diverse electrocatalytic applications.