Ru Atoms Research Articles

Radical enhanced intersystem crossing mechanism, electron spin dynamics of high spin states and their applications in the design of heavy atom-free triplet photosensitizers.

Heavy atom-free triplet photosensitizers (PSs) can overcome the high cost and biological toxicity of traditional molecular systems containing heavy atoms (such as Pt(II), Ir(III), Ru(II), Pd(II), Lu(III), I, or Br atoms) and, therefore, are developing rapidly. Connecting a stable free radical to the chromophore can promote the intersystem crossing (ISC) process through electron spin exchange interaction to produce the triplet state of the chromophore or the doublet (D) and quartet (Q) states when taking the whole spin system into account. These molecular systems based on the radical enhanced ISC (REISC) mechanism are important in the field of heavy atom-free triplet PSs. The REISC system has a simple molecular structure and good biocompatibility, and it is especially helpful for building high-spin quantum states (D and Q states) that have the potential to be developed as qubits in quantum information science. This review introduces the molecular structure design for the purpose of high-spin states. Time-resolved electron paramagnetic resonance (TREPR) is the most important characterization method to reveal the properties of these molecular systems, generation mechanism and electron spin polarization (ESP) of the high spin states. The spin polarization manipulation of high spin states and potential application in the field of quantum information engineering are also summarized. Moreover, molecular design principles of the REISC system to obtain long absorption wavelength, high triplet state quantum yield and long triplet state lifetime are introduced, as well as applications of the compounds in triplet-triplet annihilation upconversion, photodynamic therapy and bioimaging. This review is useful for the design of heavy atom-free triplet PSs based on the radical-chromophore molecular structure motif and the study of the photophysics of the compounds, as well as the electron spin dynamics of the multi electron system upon photoexcitation.

Heterocyclic (pyrazine)carboxamide Ru(ii) complexes: structural, experimental and theoretical studies of interactions with biomolecules and cytotoxicity.

Treatments of N-(1H-benzo[d]imidazol-2-yl)pyrazine-2-carboxamide (HL1) and N-(benzo[d]thiazol-2-yl)pyrazine-2-carboxamide carboxamide ligands (HL2) with [Ru(p-cymene)Cl2]2 and [Ru(PPh3)3Cl2] precursors afforded the respective Ru(ii) complexes [Ru(L1)(p-cymene)Cl] (Ru1), [Ru(L2)(p-cymene)Cl] (Ru2), [Ru(L1)(PPh3)2Cl] (Ru3), and [Ru(L2)(PPh3)2Cl] (Ru4). These complexes were characterized by NMR, FT-IR spectroscopies, mass spectrometry, elemental analyses, and crystal X-ray crystallography for Ru2. The molecular structure of complex Ru2 contains one mono-anionic bidentate bound ligand and display pseudo-octahedral piano stool geometry around the Ru(ii) atom. The interactions with calf thymus DNA (CT-DNA) and bovine serum albumin (BSA) were investigated by spectroscopic techniques. The experimental binding studies suggest that complexes Ru1-Ru4 interact with DNA, primarily through minor groove binding, as supported by molecular docking results. Additionally, these complexes exhibit strong quenching of the fluorescence of tryptophan residues in BSA, displaying static quenching. The in vitro cytotoxicity studies of compounds Ru1-Ru4 were assessed in cancer cell lines (A549, PC-3, HT-29, Caco-2, and HeLa), as well as a non-cancer line (KMST-6). Compounds Ru1 and Ru2 exhibited superior cytotoxicity compared to Ru3 and Ru4. The in vitro cytotoxicity and selectivity of compounds Ru1 and Ru2 against A549, PC-3, and Caco-2 cell lines surpassed that of cisplatin.

Manipulating the interfacial water structure by electron redistribution for the hydrogen evolution reaction.

The sluggish dissociation of water in alkaline electrolytes significantly hinders the kinetics of the hydrogen evolution reaction (HER), particularly on surfaces of Ru-based catalysts. The structure of water at the water-catalyst interface influences this dissociation process, yet controlling the configuration of water molecules is challenging due to their random distribution. In this study, a NiRu alloy supported on nitrogen-doped carbon (NiRu/NC) is selected as a model catalyst to investigate the electron distribution of the catalyst manipulating the adsorption configuration and orientation of water molecules. The introduction of Ni leads to charge transfer from Ni to Ru atoms within the NiRu alloy, causing a notable redistribution of charge that strengthens the local electric fields surrounding the NiRu alloy. These electron-rich Ru sites attract K+ cations to the surface, resulting in an increased presence of K+ cation-hydrated water molecules, which is an H-down configuration with a reduced Ru-H distance. This phenomenon is confirmed by in situ Raman spectroscopy. Consequently, NiRu/NC exhibits outstanding HER performance, achieving low overpotentials of 16 and 344 mV at current densities of 10 and 1000 mA cm-2, respectively.

Ru doping and interface engineering synergistically boost the electrocatalytic performance of a WP/WP2 nanosheet array for an efficient hydrogen evolution reaction.

The surface electronic structure and morphology of catalysts have a crucial impact on the electrocatalytic hydrogen evolution reaction performance. This work reports on the fabrication of a Ru-doped WP/WP2 heterojunction nanosheet array electrode via a one-step phosphating treatment of a Ru-doped WO3 precursor. Benefitting from the large electrochemical active surface of nanosheet arrays, rich WP/WP2 heterojunction interface, and trace Ru atom doping, the catalyst has a fairly low overpotential of 58.0 mV at 10 mA cm-2 and a Tafel slope of 50.71 mV dec-1 in acid solution toward the electrocatalytic HER. Further, theoretical calculations unveil that Ru atom doping and interface effect synergistically optimized the electronic structure of the catalyst and hence weakened the adsorption capacity of the catalyst surface toward hydrogen (H), which lowered the Gibbs free energy (ΔGH*) and consequently effectively improved the HER performance. This work may open new avenues for developing advanced nanoarray electrodes with efficient electrochemical energy conversion.

Two-dimensional multiferroic RuClF/AgBiP2S6 van der Waals heterostructures with valley splitting properties and controllable magnetic anisotropy.

The investigation of new properties in two-dimensional (2D) multiferroic heterostructures is significant. In this work, the electronic properties and magnetic anisotropy energies (MAEs) of 2D multiferroic RuClF/AgBiP2S6 van der Waals (vdW) heterostructures are systematically studied by first principles calculations based on density functional theory (DFT). The Hubbard on-site Coulomb parameter (U) of Ru atoms is necessary to account for the strong correlation among the three-dimensional electrons of Ru. RuClF/AgBiP2S6 heterostructures in different polarizations (RuClF/AgBiP2S6-P↑ and RuClF/AgBiP2S6-P↓) are ferromagnetic semiconductors with stable structures. Valley polarizations are present in the band structures of RuClF/AgBiP2S6 heterostructures with spin-orbit coupling (SOC), the valley splitting energies of which are 279 meV and 263 meV, respectively. The MAEs of RuClF/AgBiP2S6 heterostructures indicate perpendicular magnetic anisotropy (PMA), which are primarily attributed to the differences in matrix elements within Ru (dyz, dz2) orbitals. In addition, valley splittings and MAEs of RuClF/AgBiP2S6 heterostructures are modified at different biaxial strains. Specifically, the highest valley splittings are 283 meV and 287 meV at ε = 2%, while they disappear at ε = -6%. The PMA of RuClF/AgBiP2S6-P↑ is gradually decreased at biaxial strains of -6% to 2%, and MAE is transformed into in-plane magnetic anisotropy (IMA) at ε = 4%. RuClF/AgBiP2S6-P↓ maintains PMA at different strains. The study of non-volatile electrical control of valley splitting phenomena in multiferroic RuClF/AgBiP2S6 heterostructures is crucial in the field of valleytronic devices, which has important theoretical significance.

Alkaline-earth-metal regulated metal carbides with bioinspired gradient OH spillover for efficient and long-lasting direct seawater electrolysis

Alkaline-earth-metal and Ru atom co-engineered catalysts with a gradient OH spillover pathway on metal carbide have been realized with retard formation of precipitates and efficient proton supply for efficient and long-lasting seawater electrolysis.

Coordination engineering of single-atom ruthenium in 2D MoS2 for enhanced hydrogen evolution.

This study investigates the enhancement of catalytic activity in single-atom catalysts (SACs) through coordination engineering. By introducing non-metallic atoms (X = N, O, or F) into the basal plane of MoS2 via defect engineering and subsequently anchoring hetero-metallic Ru atoms, we created 10 types of non-metal-coordinated Ru SACs (Ru-X-MoS2). Computations indicate that non-metal atom X significantly modifies the electronic structure of Ru, optimizing the hydrogen evolution reaction (HER). Across acidic, neutral, and alkaline electrolytes, Ru-X-MoS2 catalysts exhibit significantly improved HER performance compared with Ru-MoS2, even surpassing commercial Pt/C catalysts. Among these, the Ru-O-MoS2 catalyst, characterized by its asymmetrically coordinated O2-Ru-S1 active sites, demonstrates the most favorable electrocatalytic behavior and exceptional stability across all pH ranges. Consequently, single-atom coordination engineering presents a powerful strategy for enhancing SAC catalytic performance, with promising applications in various fields.

Significant inhibition of secondary pollution in the catalytic oxidation of chloroaromatics over a bifunctional Ru1/CeO2 single-atom catalyst

Single atomic Ru supported CeO2 seems to be a more promising and selective catalyst for chlorobenzene oxidation than RuO2 NPs, which enables the inhibition of HCl conversion to Cl2 and stepwise formation of polychlorinated by-products.

Atomic Ru clusters supported on CeO2(110) for effectively catalyzing the electrochemical N2 reduction reaction: insights from density functional theory

The electrochemical nitrogen reduction reaction on Ru3/CeO2(110).

Electronic structure optimization of metal–phthalocyanine via confining atomic Ru for all-pH hydrogen evolution

Electronic structure optimization of two-dimensional metal phthalocyanine through confined atomic Ru species eliminates electrocatalytic kinetic differences for all-pH hydrogen evolution.

Multi-interface anchoring enables atomic-level dispersion of Ru for efficient water oxidation

Although noble metal-based catalysts are expensive, they are still the most promising oxygen evolution reaction (OER) electrocatalysts. Therefore, it is desirable to reduce the load of the precious metal without affecting the OER performance of the catalyst. In this work, we have innovatively proposed a strategy of interfacial anchoring of Ru atoms and successfully achieve the dispersion of precious metal ruthenium atoms in cross-growing NiS and NiSe multifaceted structures. The dispersion of Ru ensures Ru–NiS/NiSe/NF more active sites and more adequate contact with the electrolyte, which further improves the oxygen production property of the catalyst. As a direct outcome, the target catalyst (Ru–NiS/NiSe/NF) only requires low overpotential of 453 mV to excite a current density of 1000 mA cm−2. Meanwhile, it can remain stable to catalyze the OER for more than 50 h (200 mA cm−2), which gives it great application potential in future large-scale electrolytic water processes. This work provides a new perspective for the efficient utilization of precious metal for designing the efficient and stable OER electrocatalyst.

Single Ru Atom Supported on B-Doped Graphyne as an Efficient Electrocatalyst for the Nitrogen Reduction Reaction

Single Ru Atom Supported on B-Doped Graphyne as an Efficient Electrocatalyst for the Nitrogen Reduction Reaction

Enhanced ruthenium selectivity for the conversion of FAMEs to diesel-range alkanes by surface decoration of FeOx species

Ruthenium-based catalysts have been widely used in the lignin depolymerization and polystyrene hydrogenolysis reactions due to its superior hydrogenolysis activity for C-O and C-C bonds. However, serious cleavage of C-C bonds at high temperatures greatly limits its application in the production of green biodiesel from the conversion of natural oils and bio-derived fatty esters. In this work, we found that introducing a suitable second less-reactive metal (e.g., Fe, Zn) can effectively suppress the hydrogenolysis activity of ruthenium (Ru) metal for C-C bonds and exhibit a high selectivity (>90 %) to diesel-range alkanes (C15-C18 alkanes) in the conversion of fatty acid methyl esters (FAMEs) even at high reaction temperature (250 °C) over the Ru1Fe0.5 catalyst, while an obvious cracking reaction was observed from 210 °C over the monometallic Ru catalyst. Detailed characterization and theoretical calculation results reveal that the introduction of Fe species in the RuFe catalysts weakens the interaction between catalyst and the resulting alkanes, which inhibits the cracking of alkanes. Specifically, adding Fe species breaks the ensemble of Ru atoms and decreases the binding affinity of metallic Ru for H2, which suppresses the activity of Ru metal for the hydrogenolysis of C-C bonds and exhibits a high selectivity to diesel-range alkanes. This research provides valuable information for improving the hydrodeoxygenation (HDO) selectivity of Ru-based catalysts while inhibiting its high hydrogenolysis activity for C-C bonds.

CO Oxidation Behavior of Pt/RuO2-Sphere Catalyst in Acidic Electrolyte

Polymer electrolyte fuel cells (PEFCs) are one of the candidates for the next-generation power source. PtRu alloy catalyst is used as an anode catalyst because it has high CO poisoning tolerance. It is well known that PtRu alloy has high CO poisoning tolerance because of the bifunctional mechanism and the ligand effects of the Ru atom working as the co-catalyst. However, the Ru atom dissolves during the operation of PEFCs, such as start-up/shut-down, and then the CO poisoning tolerance becomes low. The author reported using ruthenium oxide nanosheet (RuO2ns) acted as high stable co-catalyst [1]. The composition catalyst of traditional Pt/C and RuO2ns (RuO2-Pt/C) showed high CO poisoning tolerance and long life. But the high CO poisoning tolerance site in the RuO2ns-Pt/C catalyst was limited to the very close position of Pt nanoparticles and RuO2ns. Thus, the CO poisoning tolerance was uneven, even within the same catalyst. On the other hand, we reported that new catalyst support with the sphere shape composited by the reduced graphene oxide wall provided high substance diffusion and Pt utilization rate [2]. It is expected that the spherical catalyst support composed from the RuO2ns wall provides complete contact with Pt nanoparticles and not only exquisite CO poisoning tolerance but also high Pt utilization. In this study, the new spherical catalyst support with the RuO2ns wall was synthesized and supported Pt nanoparticles, and its CO oxidation ability was evaluated by CO stripping voltammetry. The spherical catalyst support (RuO2-sphere) was composed of a SiO2 bead as a core and the RuO2ns wall, and its synthesis method was similar to the previous work [2]. Concretely, this study changed the wall material from graphene oxide to RuO2ns. And the Pt complex adsorbing on a RuO2-sphere was reduced by heating reflux with hydrazine at 100°C and 24 hours in ethanol solvent. After water washing, Pt-supported RuO2-sphere (Pt/RuO2-sphere) was obtained. The morphology, crystal structure, and electron state of the Pt/RuO2-sphere were evaluated by SEM, XRD, and XPS, respectively.A three-electrode cell, which is composed of a working electrode, Pt counter, Ag/AgCl reference electrode, and 0.1 M HClO4 electrolyte, was used for the electrochemical measurements, and the measurement temperature was 60°C. This study converted the potentials from Ag/AgCl reference to RHE reference. The CO stripping voltammetry was conducted in the following steps. CO gas was introduced had flowed into the electrolyte for two minutes to adsorb on the metal surface while its potential was kept at 0.05 V. The inert gas purged out excess CO gas in the electrolyte for 30 minutes. And then, the potential was swept to 1.2 V at 10 mV s-1. SEM images of the Pt/RuO2-sphere showed about 500 nm sphere of RuO2-sphere and a few nanometer sizes of Pt particles. Results of XRD and XPS suggested that Pt particles were mainly metallic state and not alloying with Ru. In addition, Ru valence in Pt/RuO2-sphere was predicted at quadrivalent. The cyclic voltammogram of the Pt/RuO2-sphere had characteristic peaks attributed to both Pt and RuO2ns. Specifically, the redox peaks below 0.4 V and at 0.8V-1.2V could be assigned the hydrogen adsorption/desorption and redox of the Pt surface, respectively. In addition, the unique redox peaks of RuO2ns were also observed around 0.6 V. The estimated on-set potential of the CO oxidation peak in the Pt/RuO2-sphere was at 0.36 V, and this value was superior to that of traditional Pt/C and near that of PtRu/C. The CO oxidation peak of the Pt/RuO2-sphere was sharply compared to the composite catalyst of Pt/C and RuO2ns in previous work. This change in peak shape was thought to be attributed to the expansion of the contact sites between the Pt nanoparticles and the RuO2ns surface.Developed Pt/RuO2-sphere catalyst, which had the RuO2ns wall and spherical shape, showed high CO poisoning catalyst as well as PtRu/C.[1] T. Saida, et al., Electrochim. Acta, 55, 857–864 (2010).[2] T. Saida, et al., Energy & Fuels, 36, 1027-1033 (2022).

Surface Activation by Single Ru Atoms for Enhanced High-Temperature CO2 Electrolysis.

Cathodic CO2 adsorption and activation is essential for high-temperature CO2 electrolysis in solid oxide electrolysis cells (SOECs). However, the component of oxygen ionic conductor in the cathode displays limited electrocatalytic activity. Herein, stable single Ruthenium (Ru) atoms are anchored on the surface of oxygen ionic conductor (Ce0.8 Sm0.2 O2-δ , SDC) via the strong covalent metal-support interaction, which evidently modifies the electronic structure of SDC surface for favorable oxygen vacancy formation and enhanced CO2 adsorption and activation, finally evoking the electrocatalytic activity of SDC for high-temperature CO2 electrolysis. Experimentally, SOEC with the Ru1 /SDC-La0.6 Sr0.4 Co0.2 Fe0.8 O3-δ cathode exhibits a current density as high as 2.39 A cm-2 at 1.6 V and 800 °C. This work expands the application of single atom catalyst to the high-temperature electrocatalytic reaction in SOEC and provides an efficient strategy to tailor the electronic structure and electrocatalytic activity of SOEC cathode at the atomic scale.

Surface Activation by Single Ru Atoms for Enhanced High‐Temperature CO2 Electrolysis

AbstractCathodic CO2 adsorption and activation is essential for high‐temperature CO2 electrolysis in solid oxide electrolysis cells (SOECs). However, the component of oxygen ionic conductor in the cathode displays limited electrocatalytic activity. Herein, stable single Ruthenium (Ru) atoms are anchored on the surface of oxygen ionic conductor (Ce0.8Sm0.2O2‐δ, SDC) via the strong covalent metal‐support interaction, which evidently modifies the electronic structure of SDC surface for favorable oxygen vacancy formation and enhanced CO2 adsorption and activation, finally evoking the electrocatalytic activity of SDC for high‐temperature CO2 electrolysis. Experimentally, SOEC with the Ru1/SDC‐La0.6Sr0.4Co0.2Fe0.8O3‐δ cathode exhibits a current density as high as 2.39 A cm−2 at 1.6 V and 800 °C. This work expands the application of single atom catalyst to the high‐temperature electrocatalytic reaction in SOEC and provides an efficient strategy to tailor the electronic structure and electrocatalytic activity of SOEC cathode at the atomic scale.

Metal-Oxygen Covalency Competition of Unsymmetrical Metal Pairs for Enhanced Bifunctional Oxygen Electrocatalysis

Rechargeable zinc-air batteries are considered promising energy conversion devices due to their inherent safety and high energy-to-cost ratio. However, the sluggish kinetics of oxygen evolution reaction and oxygen reduction reaction during the charging-discharging process lead to low round trip efficiency and power density. The synthesis of efficient and stable bifunctional oxygen electrocatalysts constitutes the bottleneck to construct applicable ZABs.Here, we report an Mn-doped ruthenium oxide electrocatalyst that exhibits remarkable ORR/OER activity, with a low potential gap of 0.62V between the half-wave potential of ORR and the OER potential at 10mA cm-2. The Mn-RuO2 assembled ZABs present a high power density of 179 mW cm-2 and long lifespans of 800 h. Metal covalency competition induces surface Mn atoms shows more favorable adsorption behavior for ORR and Ru atoms shows more favorable adsorption behavior for OER. The charge redistribution between asymmetrical Ru-O-Mn pairs results in dual actives sites towards OER/ORR. The surface ruthenium stabilizes the O* intermediate due to the weaker hybridization of the lattice Ru-O bond. The upshift of the dz2 orbital relieves the over-binding of the critical intermediates OH* on the Mn atom. Such dual Ru-Mn sites minimized the OER/ORR activity gap restricted by scaling relationships. Our findings rationalize the double active sites mechanism in Mn-RuO2 electrocatalyst and provide a strategy to enhance bifunctional catalytic performance. Figure 1

Ru Perovskites with Enhanced Activity and Durability for the OER in Acid Media

Iridium- and Ruthenium based catalysts are the only feasible ones for the oxygen evolution reaction (OER) in acidic media. The high price and scarcity of Ir is a major hurdle to realize electrolysis in the GW-scale. Ru-based catalysts can be suitable candidates to replace Ir, since they are more active for the OER than Ir. However, Ru catalysts lack sufficient stability during the OER. This is because, Ru tends to form soluble upper oxides e.g. RuO4 at high voltages (> 1.4 V). Previous studies reveal that Na- or K-doping can increase Ru’s durability during the OER.1,2 However, recent studies demonstrate that Ru’s activity and stability depends on the structure and composition of the Ru-based catalyst.3 In this work, we report a series of Ru double perovskites, namely R2NiRuO6 (R = Pr, Nd, Tb, Dy, Y, Ho and Er)4 with low ruthenium content and high OER activity in acidic electrolyte. The oxides have been synthesized by wet-chemistry and thoroughly characterized by XRD (Rietveld refinement), TEM and XPS.The OER was studied in the rotating ring disk (RDE) configuration in 0.1 M HClO4. Due to the absence of Sr or alkali metals in their structure, in addition to displaying high initial OER activity, the perovskites are stable during OER cycles between 1.1 and 1.7 V, with Dy2NiRuO6 being stable at least during 500 consecutive cycles (see Figures 1a and 1b).Characterization results reveal that Ru-O distances in the perovskites follow the order Dy<Er<Y<Ho<Tb<Nd<Pr. As shown in Figure 1c, the OER activity, i.e., the potential recorded at 10 mA·cm-2, follows the same trend. Also, the durability of the catalysts follows the same trend.The smaller Ru-O distance indicates a higher oxidation state of Ru atoms in Dy2NiRuO6. In addition, the gives symmetry and order to the structure. perovskite, making it more stableXPS and TEM-EDS post-mortem studies of Dy2NiRuO6 reveal a loss of Ni after 500 OER cycles and the presence of Ru3+ cations, being the main cause of the loss of OER activity.The R2NiRuO6 double perovskites reported in this work are the first example of highly active and stable Ru-based perovskites for the OER in acidic electrolyte that can opens the way for the replacement of Ir from state of the art PEMWEs.(1) Retuerto, M.; Pascual, L.; Calle-Vallejo, F.; Ferrer, P.; Gianolio, D.; Pereira, A. G.; García, Á.; Torrero, J.; Fernández-Díaz, M. T.; Bencok, P.; Peña, M. A.; Fierro, J. L. G.; Rojas, S. Na-Doped Ruthenium Perovskite Electrocatalysts with Improved Oxygen Evolution Activity and Durability in Acidic Media. Nat. Commun. 2019, 10 (1), 2041. https://doi.org/10.1038/s41467-019-09791-w.(2) Rodríguez-García, I.; Galyamin, D.; Pascual, L.; Ferrer, P.; Peña, M. A.; Grinter, D.; Held, G.; Abdel Salam, M.; Mokhtar, M.; Narasimharao, K.; Retuerto, M.; Rojas, S. Enhanced Stability of SrRuO3 Mixed Oxide via Monovalent Doping in Sr1-XKxRuO3 for the Oxygen Evolution Reaction. J. Power Sources 2022, 521, 230950. https://doi.org/10.1016/j.jpowsour.2021.230950.(3) Paoli, E. A.; Masini, F.; Frydendal, R.; Deiana, D.; Malacrida, P.; Hansen, T. W.; Chorkendorff, I.; Stephens, I. E. L. Fine-Tuning the Activity of Oxygen Evolution Catalysts: The Effect of Oxidation Pre-Treatment on Size-Selected Ru Nanoparticles. Catal. Today 2016, 262, 57–64. https://doi.org/10.1016/j.cattod.2015.10.005.(4) Kayser, P.; Alonso, J. A.; Muñoz, A.; Fernández-Díaz, M. T. Structural and Magnetic Characterization of the Double Perovskites R2NiRuO6 (R = Pr-Er): A Neutron Diffraction Study. Acta Mater. 2017, 126, 114–123. https://doi.org/10.1016/j.actamat.2016.12.024. Figure 1

Single Ru atoms dispersed on MoSe2/MXene nanosheets with multiple interfaces for enhanced acidic hydrogen evolution

Exposing more catalytic active sites is an effective strategy to enhance the catalyst activity for hydrogen evolution reaction (HER). Herein, Ti3C2Tx MXene served as a substrate to load thin and curved 2H–MoSe2 nanosheets by a typical hydrothermal method, forming MoSe2/MXene heterointerface with the fully exposed Mo edge sites. And then, atomically dispersed Ru single atoms (RuSAs) were successfully anchored on the MoSe2/MXene (RuSAs@MoSe2-MXene). The X-ray absorption near edge structure (XANES) demonstrates that Ru is loaded as single atoms on MoSe2 and MXene. The prepared sample exhibits improved catalytic activity with a small overpotential of 49 mV at 10 mA cm−2 and a low Tafel slope of 52 mV dec−1 for HER in 0.5 M H2SO4. It also exhibits excellent stability with a small attenuation voltage of 10 mV for 120 h at 10 mA cm−2 in 0.5 M H2SO4. When assembled into a two-electrode system of RuSAs@MoSe2-MXene||RuO2, it only requires a relatively low potential of 1.626 V at 10 mA cm−2 to drive overall water splitting (OWS). Control experiments disclose the highly improved performance can be primarily attributed to the introduced RuSAs and MoSe2/MXene heterointerfaces exposing more active sites of Ru and Mo. Moreover, the high conductivity of MXene can increase charge transfer in HER process. The interface engineering with multiple interfaces can provide fresh impetus for the development of efficient HER catalysts.

Competitive adsorption: Inhibiting the hydroxyl poisoning effect on lattice-confined Ru atoms in metal carbides nanoislands for boosting hydrogen production

Ruthenium (Ru)-based electrocatalysts are regarded as promising for applications in hydrogen evolution reactions (HER) due to their suitable metal-hydrogen (M-H) bonding energy. However, the strong affinity for adsorbed hydroxyl groups (OHad) leads to the inactivation of Ru active sites, leading to unsatisfactory performance in practical HER applications. Herein, a competitive adsorption strategy for the design of crystalline lattice-confined atomic Ru in Tungsten Carbide Nanoislands is reported. Benefiting from the unique "island–multi-atoms" structural features, Ru/WCx exhibits ultra-high mass activity (6000 mA mg−1) and excellent turnover frequency (3.89 H2−1) at − 100 mV vs. RHE, which is 9.5 and 51.2 times higher than commercial 20% Pt/C, respectively. In-depth mechanistic analysis demonstrates that the strength of Ru-OHad is regulated by the oxophilicity of W atoms and the stronger W-OHad bond to alleviate Ru site inactivation, thus enhancing the HER activity. This strategy provides a novel concept for designing advanced catalysts.