Ultrasmall Clusters Research Articles

RuCo clusters stabilized by Co single atoms: alloying effect and small size effect facilitate hydrogen electrocatalysis kinetics

The development of efficient catalysts is essential to promote slow hydrogen reaction kinetics in alkaline solutions. Herein, an ultrathin ZIF-derived efficient HOR/HER electrocatalyst, with Co single-atom-anchored RuCo clusters on N-doped graphitized carbon nanosheets (RuCo/SANC NS), is designed and constructed by a step-by-step calcination strategy. In the RuCo/SANC NS, Co atoms dispersed in carbon nanosheets induce the formation of ultrasmall RuCo clusters and stabilize the RuCo clusters. Abundant coordinatively unsaturated Ru sites are formed on the surface of RuCo clusters due to the small size effect. The electronic structure of the Ru site is regulated by the alloying effect with Co, optimizing the adsorption energy to *H and *OH and accelerating the HER/HOR kinetics. The RuCo/SANC NS catalyst exhibits excellent mass activity with HER of 13.58 A/mgRu and HOR of 3.85 A/mgRu, which are about 35.35 and 48.13 times that of Pt/C.

Enhanced moisture resistance and catalytic stability of ethylene oxidation at room temperature by the ultrasmall MnOx cluster/Pt hetero-junction

Ethylene elimination can effectively inhibit the rapid aging of fruits and vegetables in storage and transportation. Improving the low-temperature activity, moisture resistance, and stability of Pt based catalysts is a challenge for catalytic oxidation of ethylene which is an effective elimination method. Herein, we constructed ultrasmall MnOx cluster (< 1 nm) on Pt particles via an alloy in situ transformation strategy, which created a large number of MnOx/Pt interfaces. Among all of the samples, 1.89Pt2.20Mn/TiO2 showed the highest catalytic activity in the oxidation of ethylene at a space velocity of 20,000 mL/(g h): T50% = 34 oC and T90% = 43 oC, specific reaction rate at 35 oC = 33.0 µmol/(gPt s), and turnover frequency at 35 oC = 6.5 × 10–3 s−1. In addition, Pt2.20Mn/TiO2 also exhibited better water resistance and stability than Pt/TiO2. The results of XPS, H2O-TPD, C2H4-TPD, in situ DRIFTS, and H218O isotopic tracing characterization revealed that the MnOx/Pt interfacial sites accelerated desorption of CO2 and enhanced the activation of surface active oxygen species (O2 to O22−). Meanwhile, the numerous interfaces provide more active sites for ethylene adsorption and activation, reducing the inhibitory effect of adsorbed water on ethylene adsorption. It was concluded that the prohibited CO2 adsorption, and increased adsorbed oxygen species were responsible for the excellent catalytic performance and good stability of 1.89Pt2.20Mn/TiO2, while the more active sites for ethylene adsorption and activation were responsible for the good water resistance of 1.89Pt2.20Mn/TiO2.

Surface microstructure modulation boosting electron transfer between Pt clusters and carbon nitrogen for effective photocatalysis

Tuning the microstructure of the catalyst surface is crucial for the loading of the co-catalyst, especially influencing the electron transfer and the size of the co-catalyst. However, influence of co-catalyst loading, related to the surface structure of the catalysts, is largely ignored. Here in, nitrogen vacancies were introduced to regulate the microstructure of carbon nitrogen and using this amorphous carbon nitride (ACN) with nitrogen vacancies as a substrate to provide atomic anchoring sites as well as electron sink to prevent Pt from further agglomeration. Experimental and theoretical results show that nitrogen vacancies were electron acceptors, which beneficial to reduce [PtCl6]2− by photo-generated electrons and consequently stabilize Pt ultra-small clusters located on the ACN. Furthermore, by combing structure and carrier behaviors, we infer that Pt ultra-small clusters stable location comes from the strong interaction between Pt and nitrogen vacancies. Pt ultra-small clusters improve electron transfer and boost photocatalytic hydrogen production. A delicate design modulates the catalyst microstructure to enhance interaction between the catalyst and the co-catalyst, resulting in a smaller co-catalyst size and provides a mean to create and optimize small size Pt-loaded and highly active photocatalysts.

Quantum size effect to induce colossal high-temperature energy storage density and efficiency in polymer/inorganic cluster composites.

Polymer dielectrics need to operate at high temperatures to meet the demand of electrostatic energy storage in modern electronic and electrical systems. The polymer nanocomposite approach, an extensively proved strategy for the performance improvement, encounters the bottleneck of reduced energy density and poor discharge efficiency beyond 150°C. Here, we report a polymer/metal oxide cluster composite prepared based on the "site isolation" strategy. Capitalizing on the quantum size effect, the bandgap and surface defect states of the ultra-small inorganic clusters (2.2nm diameter) are modulated to markedly differ from the regular-sized nanoparticles. Experimental results in conjunction with computational simulation demonstrate that, the presence of ultra-small inorganic clusters can introduce more abundant, deeper traps in the composite dielectric with respect to the conventional polymer/nanoparticle blends. Unprecedented high-temperature capacitive performance including colossal energy density (6.8 Jcm-3 ), ultra-high discharge efficiency (95%) and superior stability at different electric field frequencies, are achieved in these polymer/cluster composites up to 200°C. Along with the advantages in material preparation (inexpensive precursors and one-pot synthesis), such polymer/inorganic cluster composite approach is promising for high-temperature dielectric energy storage in practical power apparatus and electronic devices. This article is protected by copyright. All rights reserved.

X-ray Absorption Spectroscopy of Phosphine-Capped Au Clusters

The structural determination of ultrasmall clusters remains a challenge due to difficulties in crystallisation. Often the atomically precise clusters undergo structural change under the influence of the environment. X-ray absorption spectroscopy (XAS) can be an attractive tool to study the electronic and geometric properties of such clusters deposited onto various supports under in situ conditions. Herein, [Au6(dppp)4](NO3)2, [Au9(PPh3)8](NO3)3, [Au13(dppe)5Cl2]Cl3, and Au101(PPPh3)21Cl5 clusters were studied using XAS. The clusters exhibited distinct features compared to bulk gold. XANES results show a systematic increase in the absorption edge energy and white line intensity, with a decrease in cluster nuclearity. The EXAFS of clusters are sensitive to nuclearity and ligands and were fitted with their known crystal structures. This study advances the understanding of the phosphine-ligated metal clusters relevant to practical applications in catalysis and sensing.

Deducing subnanometer cluster size and shape distributions of heterogeneous supported catalysts

Infrared (IR) spectra of adsorbate vibrational modes are sensitive to adsorbate/metal interactions, accurate, and easily obtainable in-situ or operando. While they are the gold standards for characterizing single-crystals and large nanoparticles, analogous spectra for highly dispersed heterogeneous catalysts consisting of single-atoms and ultra-small clusters are lacking. Here, we combine data-based approaches with physics-driven surrogate models to generate synthetic IR spectra from first-principles. We bypass the vast combinatorial space of clusters by determining viable, low-energy structures using machine-learned Hamiltonians, genetic algorithm optimization, and grand canonical Monte Carlo calculations. We obtain first-principles vibrations on this tractable ensemble and generate single-cluster primary spectra analogous to pure component gas-phase IR spectra. With such spectra as standards, we predict cluster size distributions from computational and experimental data, demonstrated in the case of CO adsorption on Pd/CeO2(111) catalysts, and quantify uncertainty using Bayesian Inference. We discuss extensions for characterizing complex materials towards closing the materials gap.

Electronic and Lattice Engineering of Ruthenium Oxide towards Highly Active and Stable Water Splitting

AbstractThe development of efficiently active and stable bifunctional noble‐metal‐based electrocatalysts toward overall water splitting is urgent and challenging. In this work, a rutile‐structured ruthenium‐zinc solid solution oxide with oxygen vacancies (Ru0.85Zn0.15O2‐δ) is developed by a simple molten salt method. With naturally abundant edges of ultrasmall nanoparticles clusters, Ru0.85Zn0.15O2‐δ requires ultralow overpotentials, 190 mV for acidic oxygen evolution reaction (OER) and 14 mV for alkaline hydrogen evolution reaction (HER), to reach 10 mA cm−2. Moreover, it shows superior activity and durability for overall water splitting in different electrolytes. Experimental characterizations and density functional theory calculations indicate that the incorporation of Zn and oxygen vacancies can optimize the electronic structure of RuO2 by charge redistribution, which dramatically suppresses the generation of soluble Rux&gt;4 and allows optimized adsorption energies of oxygen intermediates for OER. Meanwhile, the incorporation of Zn can distort local structure to activate the dangling O atoms on the distorted Ru0.85Zn0.15O2‐δ as proton acceptors, which firmly bonds the H atom in H2O* to stabilize the H2O and considerably improves the HER activity.

Understanding structure-performance relationships of CoOx/CeO2 catalysts for NO catalytic oxidation: Facet tailoring and bimetallic interface designing

Crystalline structure and bimetallic interaction of metal oxides are essential factors to determine the catalytic activity. Herein, three different CoOx/CeO2 catalysts, employing CeO2 nanorods (predominately exposed {110 facet), CeO2 nanopolyhedra ({111} facet) and CeO2 nanocubes ({100} facet) as the supports, are successfully prepared for investigating the effect of exposed crystal facets and bimetallic interface interaction on NO oxidation. In comparison with the {111} and {100} facets, the exposed crystal facet {110} exists the best superiority to anchor and stabilize Co species. Moreover, ultra-small CoOx clusters composed of strong Co-O coordination shells with minor Co-O-Ce interaction are formed and uniformly dispersed on the CeO2 nanorods. Structural characterizations reveal that the active exposed crystal facet {110} and the strong bimetallic interface interaction in CoOx/CeO2-nanorods (R-CC) result in more structural defect, endowing it with abundant oxygen vacancies, excellent reducibility and strong adsorption capacity. The DRIFTs spectra further indicate that the exposed crystal facet {110} has a significant promoting effect on the strength of nitrates compared with {111} and {100} facets. The bimetallic interface interaction not only significantly facilitates the formation of nitrate species at lower temperature, but also effectively suppresses the generation of sulfate and lower the sulphation rate. Therefore, R-CC catalyst exhibits the maximum NO oxidation activity with the conversion of 86.4 % at 300 °C and still sustains its high activity under cyclic condition or 50 ppm SO2. The provided crystalline structure and interaction-enhanced strategy sheds light on the design of high-activity NO oxidation catalysts.

Carbon-coordinated atomic cobalt directly embedded on carbon cloth for alkaline hydrogen evolution at high current density

Electrocatalysts for high current density hydrogen evolution reaction (HER) under alkaline conditions is critical for the widespread application of water electrolysis. Carbon-supported single-atom catalysts (SACs) stabilized by N atoms have been demonstrated as efficient electrocatalysts, but mostly for acidic HER. For alkaline HER, although defective-, edge-, and dual-sites have been found to improve the adsorption pathways of the intermediates, there is still a great challenge to precisely synthesize those complex configurations in experiments to maximize the synergistic effects. Since C atom has relatively weak electronegativity than N atom, it can induce different charge redistribution of the metal atom center. However, the reported C-coordinated SACs were derived from the N-containing precursors, which could not exclude the influence of heteroatoms on the activity completely. Herein, we reported the synthesis of carbon-coordinated CoC4 sites and ultra-small Co cluster directly embedded on pure carbon cloth (Co-SA/CC) via the high temperature shockwave (HTS) method. The C atoms on the first coordination shell can tune the local electronic structure and up-shift the d-band center of the Co atom, thus strengthening H2O molecule adsorption and promoting water dissociation. The self-supporting electrode with CoC4 can lower the interfacial contact resistance, leading to higher HER performance compared with that of Pt/C at high current density (e.g. 1000 mA/cm2). These results provide a new insight into the fundamental understanding of design and synthesis of C-coordinated atomically dispersed catalytic sites.

Radiolytic Water Splitting Sensitized by Nanoscale Metal-Organic Frameworks.

High-energy radiation that is compatible with renewable energy sources enables direct H2 production from water for fuels; however, the challenge is to convert it as efficiently as possible, and the existing strategies have limited success. Herein, we report the use of Zr/Hf-based nanoscale UiO-66 metal-organic frameworks as highly effective and stable radiation sensitizers for purified and natural water splitting under γ-ray irradiation. Scavenging and pulse radiolysis experiments with Monte Carlo simulations show that the combination of 3D arrays of ultrasmall metal-oxo clusters and high porosity affords unprecedented effective scattering between secondary electrons and confined water, generating increased precursors of solvated electrons and excited states of water, which are the main species responsible for H2 production enhancement. The use of a small quantity (<80 mmol/L) of UiO-66-Hf-OH can achieve a γ-rays-to-hydrogen conversion efficiency exceeding 10% that significantly outperforms Zr-/Hf-oxide nanoparticles and the existing radiolytic H2 promoters. Our work highlights the feasibility and merit of MOF-assisted radiolytic water splitting and promises a competitive method for creating a green H2 economy.

Pushing the Performance Limit of Cu/CeO2 Catalyst in CO2 Electroreduction: A Cluster Model Study for Loading Single Atoms

Pushing the performance limit of catalysts is a major goal of CO2 electroreduction toward practical application. A single-atom catalyst is recognized as a solution for achieving this goal, which is, however, a double-edged sword considering the limited loading amount and stability of single-atom sites. To overcome the limit, the loading of single atoms on supports should be well addressed, requiring a suitable model system. Herein, we report the model system of an ultrasmall CeO2 cluster (2.4 nm) with an atomic precise structure and a high surface-to-volume ratio for loading Cu single atoms. The combination of multiple characterizations and theoretical calculations reveals the loading location and limit of Cu single atoms on CeO2 clusters, determining an optimal configuration for CO2 electroreduction. The optimal catalyst achieves a maximum Faradaic efficiency (FE) of 67% and a maximum partial current density of -364 mA/cm2 for CH4, and can maintain high CH4 FE values over 50% in a wide range of applied current densities (-50 ∼ -600 mA/cm2), exceeding those of the reported catalysts.

Surface anchoring of nickel sulfide clusters as active sites and cocatalysts for photocatalytic antibiotic degradation and bacterial inactivation

Achieving photocatalytic antibiotic degradation and bacterial inactivation with high efficiency remains a challenging mission to originate a clean environment. In this work, ultra-small NiS clusters were in-situ grew on photoactive ZnIn2S4 nanoflower supports to form a NiS/ZnIn2S4 heterojunction, in which a strong and surface-limited binding was formed between the NiS clusters and ZnIn2S4 supports. The in-situ formed NiS clusters not only appeased interfacial charge transfer resistance of the heterojunction but also eventuated a strong built-in electric field, resulting a fast electron migration from ZnIn2S4 to NiS clusters functioned as cocatalyst and active sites to boost the separation efficiency of photogenerated carriers. As a result, the optimal 2NiS/ZnIn2S4 heterojunction expressed a higher photocatalytic Escherichia inactivation activity (99.23 % for 3 h) and a raised antibiotic degradation performance, including tetracycline (60 % for 20 min), ofloxacin (62 % for 20 min), oxytetracycline (63 % for 20 min) compared to that of pure ZnIn2S4 (39.14 % for Escherichia inactivation and 44 % for tetracycline degradation). This work furnishes a great promise to develop inorganic clusters coupled photocatalysts for light-driven environmental application.

Spontaneous Intercluster Electron Transfer X2– + X0 → 2 X– (X = PtAu24(SCnH2n+1)18) in Solution: Promotion by Long Alkyl Chains

In this work, we systematically investigated the ligand effects on spontaneous electron transfer (ET) between alkanethiolate-protected metal clusters in solution. The donor and acceptor clusters used were [PtAu24(SCnH2n+1)18]2- (8e(Cn)) and [PtAu24(SCmH2m+1)18]0 (6e(Cm)) (n, m = 2-16), which have icosahedral Pt@Au12 cores with eight and six valence electrons, respectively. The ET rate constant (kET) from 8e(Cn) to 6e(Cm) in benzene exhibited a novel turnover behavior as a function of the total chain length n + m: the kET decreased with n + m in the range of 4-12, whereas it monotonically increased with n + m in the range of 12-32. Electrospray ionization mass spectrometry of the mixture of 8e(Cn) and 6e(Cm) detected the dimer complex 8e(Cn)·6e(Cm), the relative population of which increased with n + m. The activation energy (Ea), determined based on the Arrhenius plots for n = m, monotonically decreased with n (≥ 6). Based on these results, we proposed that the promotion of ET by longer alkanethiolates was ascribed to two effects on the key intermediate 8e(Cn)·6e(Cm): (1) elongation of the lifetime and (2) the contraction of the distance between 8e(Cn) and 6e(Cm) due to the stronger van der Waals interaction between the longer alkyl chains. Such alkyl-chain-promoted ET is specific to ultrasmall clusters in solution because a nonuniform ligand layer could be formed due to the large curvature of the cluster core.

Synergism of Ultrasmall Pt Clusters and Basic La2O2CO3 Supports Boosts the Reverse Water Gas Reaction Efficiency

AbstractThe reverse water‐gas shift reaction (RWGS) has been regarded as a promising approach for fighting climate change caused by the excessive emission of the greenhouse gas CO2, but it still suffers from relatively poor low‐temperature reactivity. Herein, a high‐performance RWGS catalyst composed of ultrasmall Pt clusters (1.38 nm on average) anchored by La2O2CO3 support (PtNC/LOC), which possesses a record CO production rate of 2678 molCO molPt−1 h−1 with nearly 100% CO selectivity at 300 °C, is reported. The specific activity is nearly 1.5 and 7.9 fold higher than that of Pt single atoms and nanoparticles on La2O2CO3, respectively. More importantly, over 87.7% of the initial activity of PtNC/LOC remains after 80 h constant operation at 380 °C, firmly verifying the structural robustness. LOC support is essential, because of not only the moderate basicity that can boost the reaction efficiency but also the strong interaction with Pt species that can stabilize the ultrasmall particle size. Further investigations also point out the key role of the Pt clusters. The two key steps, CO2 adsorption, and CO desorption, individually prefer electron‐rich and electron‐deficient Pt species. Ultrasmall Pt clusters successfully integrate the unique surface states of single atoms and nanoparticles, thus achieving excellent low‐temperature RWGS performance.

Construction of High-Density Fe Clusters Embedded in a Porous Carbon Nitride Catalyst with Effectively Selective Transformation of Benzene

An Fe-based heterogeneous catalyst is an attractive Fenton-like catalyst for phenol synthesis due to many advantages. Nevertheless, it is challenging to control the particle size in various high-loading Fe-based materials, which limits its activity and selectivity. In this work, ultra-small Fe clusters embedded in a 3D porous interconnected open-framework g-C3N4 (denoted FeNx/CCN) were successfully fabricated by the combination of a mechanochemical reaction with one-step pyrolysis. Various characterization results showed that ultra-small Fe clusters with a high loading of 32% were uniformly distributed in the hierarchical porous carbon nitride, which offered an access for faster transportation of charge carriers. Fe sites were probably coordinated with carbon nitride by Fe2+–C≡ N–Fe3+ and Fe–Nx bonding. High-density Fe clusters could provide abundant active sites and improve the light absorption and the activating ability of H2O2. By taking advantage of semiconductor functions in combination with a rich porous structure and high-density active sites, the novel Fe cluster catalyst exhibited high activity and stability in phenol synthesis, with a maximum phenol yield of 28.1% in visible light. Combining the experimental results with Fenton chemistry, we proposed a possible photocatalytic reaction mechanism. Our work will give valuable information on the development of active metal cluster nanocatalysts for organic synthesis.

Ultrasmall Cluster Model for Investigating Single Atom Catalysis: Dehydrogenation of 1-Propanamine by Size-Selected Pt1Zr2O7 Clusters Supported on HOPG.

The selective dehydrogenation of hydrocarbons and their functionalized derivatives is a promising pathway in the realization of endothermic fuel systems for powering important technologies such as hypersonic aircraft. The recent surge in interest in single atom catalysts (SACs) over the past decade offers the opportunity to achieve the ultimate levels of selectivity through the subnanoscale design tailoring of novel catalysts. Experimental techniques capable of investigating the fundamental nature of the active sites of novel SACs in well-controlled model studies offer the chance to reveal promising insights. We report here an approach to accomplish this through the soft landing of mass-selected, ultrasmall metal oxide cluster ions, in which a single noble metal atom bound to a metal oxide moiety serves as a model SAC active site. This method allows the preparation of model catalysts in which monodispersed neutral SAC model active sites are decorated across an inert electrically conductive support at submonolayer surface coverage, in this case, Pt1Zr2O7 clusters supported on highly oriented pyrolytic graphite (HOPG). The results contained herein show the characterization of the Pt1Zr2O7/HOPG model catalyst by X-ray photoelectron spectroscopy (XPS), along with an investigation of its reactivity toward the functionalized hydrocarbon molecule, 1-propanamine. Through temperature-programmed desorption/reaction (TPD/R) experiments it was shown that Pt1Zr2O7/HOPG decomposes 1-propanamine exclusively into propionitrile and H2, which desorb at 425 and 550 K, respectively. Conversely, clusters without the single platinum atom, that is, Zr2O7/HOPG, exhibited no reactivity toward 1-propanamine. Hence, the single platinum atom in Pt1Zr2O7/HOPG was found to play a critical role in the observed reactivity.

Promotion effect of the S-1 zeolite microenvironment on confined Pd nanoparticles for the selective hydrogenation of nitrile

Zeolite-tailored encapsulation of metal nanoparticles exhibits prominent catalytic performance in many fields especially for selective hydrogenation reaction due to the modulation effect of the zeolite microenvironment. Here, Pd nanoparticles encapsulated in MFI zeolite by an in-situ encapsulation method were first used in the selective hydrogenation of nitrile into a primary amine. After introducing KOH for mediating the acid-base property of zeolite microenvironment, the as-synthesized Pd@S-1-K manifested an improved selectivity in the synthesis of primary amine from nitrile, while outperformed both commercial catalysts and conventional Pd supported on zeolite catalyst. The remarkable performance of Pd@S-1-K could be attributed to both the basic property of the S-1-K zeolite for inhibiting the side reactions and the highly dispersed and ultrasmall Pd clusters for superior catalytic activity. Besides, the best yield of 81% was achieved at 80 °C, 5 bar H2, 2 h in ammonia solution via optimization experiments, and the moderate applicability of Pd@S-1-K catalyst was obtained by substrate scope test.

Iron single atoms and clusters anchored on natural N-doped nanocarbon with dual reaction sites as superior Fenton-like catalysts

Ultra-small metal clusters have emerged as one of the most promising alternatives to heterogeneous Fenton-like catalysts. Despite the high atom utilization and structural stability of catalysts with ultra-small clusters and single-atom sites, there is still challenging for the synthesis of these catalysts due to their facile aggregation. Herein, we successfully fabricated a catalyst (Fe-NC-900) with single-atom sites and ultra-small clusters by a ball milling method combined with subsequent pyrolysis process. Fe-NC-900 showed high efficiency and superior stability in the activation of peroxymonosulfate (PMS) for catalytic oxidation of refractory organic compounds. Chemical quenching experiments, electron paramagnetic resonance (EPR), in-situ Raman spectra, and electrochemical analysis indicated that the 1O2 oxidation was the main non-radical pathway rather than the high-valent iron oxidation and electron transfer mechanism for the degradation of RhB in the Fe-NC-900/PMS system. This work provides useful insights into the design and synthesis of the catalysts with single atoms and ultra-small clusters for practical applications in Fenton-like catalytic processes.

Ordered mesoporous carbon spheres assisted Ru nanoclusters/RuO2 with redistribution of charge density for efficient CO2 methanation in a novel H2/CO2 fuel cell

Efficiently reducing carbon dioxide (CO2) into carbon chemicals and fuels is highly desirable due to the rapid growth of atmospheric CO2 concentration. In prior work, we described a unique H2/CO2 fuel cell driven by low-valued waste heat, which not only converts CO2 to methane (CH4) but also outputs electrical energy, yet the CO2 reduction rate needs to be urgently improved. Here, a novel Ru-RuO2 catalyst with heterostructure was grafted on mesoporous carbon spheres by in situ partially reducing RuO2 into ultrasmall Ru clusters (∼1 nm), in which heteroatom-doped carbon spheres as a matrix with excellent conductivity and abundant pores can not only easily confine the formation of Ru nanocluster but also are beneficial to the exposed active sites of Ru complex and the mass transport. Compared to pure RuO2 nanoparticles supported on carbon spheres, our composite catalyst boosts the CO2 conversion rate by more than 5-fold, reaching a value of 382.7 μmol gcat.-1h−1 at 170 ℃. Moreover, a decent output power density of 2.92 W m−2 was obtained from this H2/CO2 fuel cell using Ru-RuO2 embedded carbon spheres as a cathode catalyst. The Ru-RuO2 heterostructure can modify the adsorption energy of CO2 and induce the redistribution of charge density, thus boosting CO2 reduction significantly. This work not only offers an efficient catalyst for this novel H2/CO2 fuel cell but also presents a facile method to prepare Ru nanoclusters.

Nitrogen-bonded ultrasmall palladium clusters over the nitrogen-doped carbon for promoting Suzuki cross-coupling reactions

Nitrogen-bonded ultrasmall palladium clusters over the nitrogen-doped carbon for promoting Suzuki cross-coupling reactions