Ruthenium Loading Research Articles

Eco‐Friendly Preparation of Pectin‐Stabilized Ruthenium Catalyst for Hydrogen Generation from Sodium Borohydride Hydrolysis

AbstractIn this study, we report that pectin‐supported ruthenium nanoparticles (pectin@Ru0) can be easily prepared at room temperature by a simple and effective method and that they exhibit outstanding catalytic activity in the hydrolysis of sodium borohydride (NaBH4). The structure, oxidation state, morphology, and thermal studies were analyzed using XRD, XPS, SEM, TEM and TGA analysis. The kinetic performance of pectin@Ru0 biocatalyst was evaluated depending on ruthenium loading, NaBH4 concentration, NaOH concentration, temperature, reusability and storage. The pectin@Ru0 biocatalyst containing 2 wt.% Ru0 metal catalyzed the hydrolysis of 50 mM NaBH4+1 wt.% NaOH with 100 % yield. The activation energy (Ea) and the TOF values of the reaction was estimated as 54.7 kJ mol−1 and 53.1 mol H2 (mol Ru0 min) −1 at 30 °C and this is consistent with other previously reported catalysts, making it a remarkable result in comparison. Reusability and catalytic life studies reported that pectin@Ru0 biocatalyst is also highly active and relatively long‐lived catalyst in the hydrolysis of NaBH4 in a slightly basic solution.

Cerium oxide-based catalyst for low-temperature and efficient ammonia decomposition for hydrogen production research

This study prepared a series of cerium oxide-based catalysts with different metal ruthenium loadings using an initial wet impregnation method. The results demonstrate that the prepared 1.4Ru/CeO2 catalyst exhibits outstanding catalytic performance and activity stability. Under the condition where the Ru loading is only 1.4 wt%, the catalyst achieves almost complete NH3 conversion at 500 °C, with a hydrogen production rate of 16.59 mmol gcat−1 min−1. Furthermore, after a 48-h long-term test, the activity remains stable. Characterization tests show that the metal ruthenium is uniformly distributed on the surface of cerium dioxide, with particle sizes ranging from 3 to 6 nm. Notably, a structure characterized by lattice stripes overlapping between the metal and support is observed. Increasing the Ru loading can enhance the surface acidity sites of the catalyst and the interaction between the metal and the support, which plays a crucial role in the long-term stability of the catalyst. Additionally, the abundant oxygen vacancies in cerium dioxide and its low cerium oxidation-reduction potential facilitate electron transfer to ruthenium, enhancing the adsorption of NH3 and accelerating the desorption of N2.

Efficient conversion of lignin-derived phenols to cycloalkanes over bifunctional catalysts with low loading of ruthenium

Hydrodeoxygenation (HDO) reactions are extensively employed in the conversion of biomass to advanced fuels, which rely heavily on bifunctional catalysts that contain both a metal component and an acidic component. A significant challenge in the development of HDO catalysts is the need to reduce costs while simultaneously enhancing catalytic efficiency. Here, a series of Ru@W/ZrO2 catalysts with an extremely low loading of Ru (0.5 wt%) were successfully synthesized using different Ru or W loading sequences and different Ru/W mass ratios. The catalysts were applied in the HDO reaction of lignin-derived phenols, and their physical and chemical characteristics were revealed by various characterization techniques, including XRD, H2-TPD, NH3-TPD, and XPS. The results suggest that the synthesis method with post-loading Ru leads to improved exposure and utilization of the low-loaded Ru, which effectively serves as the active sites for hydrogenation in catalytic reactions. Under the same reaction conditions, the bifunctional catalyst with post-loading of Ru achieved a complete conversion of phenol into cyclohexane, while the catalyst with simultaneous loading of Ru and W only yielded 42% of cyclohexane. In addition, the Ru/W ratios have also shown significant effects on the HDO performance of the catalyst. The catalyst exhibits the highest hydrogenation activity when the Ru/W ratio is 10, which is further supported by kinetic experiments. This study highlights the significance of the loading sequence of noble metals and the metal/acid ratio in the synthesis of highly active bifunctional catalysts, and also lays the groundwork for the efficient utilization of noble metals in biomass HDO conversion.

Ruthenium supported on silicate and aluminosilicate mesoporous materials applied to selective sugar hydrogenation: Xylose to xylitol

A series of ruthenium-based catalysts supported on a set of silicate and aluminosilicate mesoporous molecular sieves was synthesized and tested in xylose hydrogenation. The materials were characterized in terms of morphology, textural properties, acidity, as well as ruthenium loading, dispersion, and oxidation state. In general, the aluminosilicates-based catalysts displayed a higher activity compared to their respective silicate supports, which can be ascribed to a higher Ru content and dispersion, enhanced by a higher acidity. The most active synthesized catalyst (Ru/Al-MCM-4) displayed an improved performance compared to a commercial Ru/C catalyst due to a better xylitol selectivity. Two modelling approaches were implemented to describe the kinetic rate. The first model was based on the hypothesis that xylose molecules and hydrogen are adsorbed in different active sites on the catalyst surface, while the second model supposes the formation of an intermediate on the catalyst surface that reacts to form xylitol. Both models gave a very good description of the experimental data.

H2 Pressure Dependence in the Homogeneously Catalyzed Guerbet Reaction of Ethanol to Butanol using Mn(I) and Ru(II)

AbstractThe homogeneously catalyzed Guerbet upgrading of ethanol to butanol can be modulated by the application of partial H2 pressure before the reaction. Ruthenium(II) PNP pincer complexes with methylene‐extended acridine‐based ligands and singly‐chelated ruthenium(II) complexes with PN ligands perform best at very low catalyst loadings and upon the application of catalyst‐specific pre‐reaction partial H2 pressure. The combination of ruthenium(II) PNP pincer complexes and manganese(I) pincer complexes with MACHO‐type PNP ligands allows for even lower ruthenium loadings while retaining low base load and consumption, thus enabling high space‐time yields, catalyst productivity and recyclability. Mechanistically, Mn is proposed to stabilize coordinatively unsaturated Ru species and allow coordination of ethoxide to Ru instead of attacking the electrophilic ligand backbone based on NMR spectroscopy and X‐ray crystallography.

Highly active Ru/TiO2 nanostructures for total catalytic oxidation of propane.

Ruthenium is a robust catalyst for a variety of applications in environmental heterogeneous catalysis. The catalytic performance of Ru/TiO2 materials, synthesized by using the deposition precipitation with urea method, was assessed in the catalytic oxidation of C3H8, varying the ruthenium loading. The highest catalytic reactivity was obtained for a Ru loading of 2 wt. % in comparison with the 1, 1.5, 3, and 4 wt. % Ru catalysts. The physicochemical properties of the synthesized materials were investigated by XRD, N2 adsorption, TEM, FT-IR pyridine, H2-TPR, and XPS. The size of ruthenium particles was found to be greatly dependent on the pretreatment gas (air or hydrogen) and the catalytic activity was enhanced by the small-size ruthenium metal nanoparticles, leading to changes in the reduction degree of ruthenium, which also increased the Brönsted and Lewis acidity. Metal to support charge transfer enhanced the reactant adsorption sites while oxygen vacancies on the interface enabled the dissociation of O2 molecules as revealed through DFT calculations. The outstanding catalytic activity of the 2Ru/TiO2 catalysts allowed to convert C3H8 into CO2 at reaction temperatures of about 100°C. This high activity may be attributed to the metal/support interaction between Ru and TiO2, which promoted the reducibility of Ti4+/Ti3+ and Ru4+/Ru0 species, and to the fast migration of TiO2 lattice oxygen in the catalyst. Furthermore, the Ru/TiO2 catalyst exhibited high stability and reusability for 30h under reaction conditions, using a GHSV of 45,000h-1. The underlying alkane-metal interactions were explored theoretically in order to explain the C-H bond activation in propane by the catalyst.

Production of Sorbitol via Hydrogenation of Glucose over Ruthenium Coordinated with Amino Styrene-co-maleic Anhydride Polymer Encapsulated on Activated Carbon (Ru/ASMA@AC) Catalyst.

Sorbitol, a product primarily derived from glucose hydrogenation, has extensive applications in the pharmaceutical, chemical and other industries. Amino styrene-co-maleic anhydride polymer encapsulated on activated carbon (Ru/ASMA@AC) catalysts were developed for efficient glucose hydrogenation and were prepared and confined Ru by coordination with styrene-co-maleic anhydride polymer (ASMA). Through single-factor experiments, optimal conditions were determined to be 2.5 wt.% ruthenium loading and a catalyst usage of 1.5 g, 20% glucose solution at 130 °C, reaction pressure of 4.0 MPa, and a stirring speed of 600 rpm for 3 h. These conditions achieved a high glucose conversion rate of 99.68% and a sorbitol selectivity of 93.04%. Reaction kinetics testing proved that the hydrogenation of glucose catalyzed by Ru/ASMA@AC was a first-order reaction, with a reaction activation energy of 73.04 kJ/mol. Furthermore, the catalytic performance of the Ru/ASMA@AC and Ru/AC catalysts for glucose hydrogenation were compared and characterized by various detection methods. The Ru/ASMA@AC catalyst exhibited excellent stability after five cycles, whereas the traditional Ru/AC catalyst suffered from a 10% decrease in sorbitol yield after three cycles. These results suggest that the Ru/ASMA@AC catalyst is a more promising candidate for high-concentration glucose hydrogenation due to its high catalytic performance and superior stability.

RuO2 supported on MOF-derived CeO2 as an efficient catalyst for selective C–H oxidation of alkylarenes in water at room temperature

Recently, MOFs as an important class of porous crystalline materials are widely utilized as carriers or catalysts in various catalytic systems. In this work, using Ce-BTC supported RuCl3 as a precursor, RuO2–CeO2 composites with high catalytic performance and excellent morphology were successfully synthesized by pyrolysis under ambient atmosphere. An efficient oxidation method for benzyl sp3 C–H bond using the synthesized composites as a heterogeneous catalyst was developed, which could effectively catalyze the selective oxidation of alkylarenes in water at room temperature, and successfully provide a variety of aryl ketone products in high yields with low catalyst dosage. The characterized results indicate that the existence of Ru (IV) is supported. The synthesized RuO2–CeO2 exhibits high activity for the gram-scale oxidation of indane with the lower ruthenium loading (3,837 h−1 TOF based on Ru). Furthermore, the heterogeneous catalyst could be utilized at least six cycles without significant loss of catalytic activity.

Study on the Effect of Solvent for Dispersing Precursor in DSA Production for Ammonia Oxidation

Objectives : An economical DSA that can be used for a longer period of time and reduce the amount of precious Ru metal required in preparing the electrode was tried to be developed by using an ionic liquid instead of the alcohols as a solvent for electrode catalyst coating when preparing the DSA and comparing the performance. In addition, the possibility of green hydrogen production using ammonia was investigated by examining the possibility of oxidation of non-aqueous ammonia with the fabricated DSA electrode.Methods : 1, 2 and 3 mg/cm2 RuO2 electrodes were prepared using butanol and imidazolium-based ionic liquid (HMIM)HSO4 as a solvent for electrode coating. To optimize conditions, the electrodes prepared using butanol and ionic liquid were compared by evaluating physical and electrochemical properties. SEM-EDS and XRD were used for evaluating physicochemical properties and cyclic voltammetry was used to investigate the possibility of oxidation of non-aqueous ammonia and to compare the electrochemical properties.Results and Discussion : Through SEM-EDS measurement before and after the accelerated life time test, it was confirmed that there was a difference depending on the solvent, but in al electrodes, the cracks on the surface before the accelerated life test was desorbed and coated Ru was desorbed, revealing the matrix of the electrode. XRD analysis showed that crystallinity of the butanol solvent electrode was smaller than that of the ionic solvent electrode. Through an accelerated life test for 1, 2, and 3 mg/cm2 RuO2 electrodes by solvent, 1 mg/cm2 RuO2 produced using an ionic solution was the shortest, ending in 16 hours. The electrode 3 mg/cm2 RuO2 was terminated at 201 h, showing the longest lifetime. Through cyclic voltammetry, all RuO2 electrodes fabricated confirmed the possibility of 7 N non-aqueous ammonia oxidation and the active area of the electrodes fabricated using butanol showed a higher total electrochemical charge than the electrodes fabricated using an ionic solution.Conclusion : As the DSA solvent affects the crystallinity of the electrode, it was shown that it affects the physical life of the electrode through the accelerated life test results. Through cyclic voltammetry, the RuO2 electrode confirmed the possibility of oxidation of 7 N non-aqueous ammonia. Through comparison of ruthenium loading amount, accelerated life test, and electrochemical total charge, it is considered that the most economical electrode is a butanol solvent 2 mg/cm 2 RuO2 electrode.

Highly Active Electrocatalyst based on Ultra-low Loading of Ruthenium Supported on Titanium Carbide for Alkaline Hydrogen Evolution Reaction

With the emerging importance of catalysts for water electrolysis, developing efficient and inexpensive electrocatalysts for water electrolysis plays a vital role in renewable hydrogen energy technology. In this study, a 1nm thickness of TiC-supported Ru catalyst for hydrogen evolution reaction (HER) has been successfully fabricated using an electron (E)-beam evaporator and thermal decomposition of gaseous CH4 in a furnace. The prepared Ru/TiC catalyst exhibited an outstanding performance for alkaline hydrogen evolution reaction with an overpotential of 55 mV at 10 mA cm−2. Furthermore, we demonstrated that the outstanding HER performance of Ru/TiC was attributed to the high surface area of the support and the metal-support interaction.

Selective CO2 reduction to methane catalyzed by mesoporous Ru-Fe3O4/CeOx-SiO2 in a fixed bed flow reactor

Development of a robust catalyst for selective reduction of CO2 directly into hydrocarbon fuels is very challenging from both energy and environmental perspectives as it offers a renewable and green route for the production of fuels. Herein, we report a novel catalyst synthesized via excess solution impregnation of Ru and Fe3O4 nanoparticles (NPs) on ceria promoted mesoporous silica SBA-15 support. The selective catalytic reduction of CO2 to methane was carried out in the presence of H2 over novel Ru-Fe3O4/CeOx-SiO2 (Ce3+/Ce4+, x=1.64) catalyst in a fixed bed reactor. The CO2 conversion was found to be 82% at 0.25 wt% ruthenium loading, 2.5 wt% iron loading, 575 K temperature, 20 bar pressure, 3000 mLg−1h−1 gas hour space velocity and H2 to CO2 mole ratio of 5:1. The close contact between ruthenium and Fe3O4 nanoparticles facilitated the reduction of CO2 through hydrogen spill-over effect at lower temperature, whereas ceria NPs acted as a promoter for this reduction reaction. The catalysts were characterized thoroughly using physicochemical techniques such as CO chemisorption, BET, TPR, TPD, XRD, SEM, HR- TEM, ICP-AES and XPS analyses. High surface area and large mesopores of silica support facilitated the fine dispersion of the active catalytic sites and oxygen vacancy as supported from the DFT study on the catalytic activity. Optimal process conditions could render much higher CO2 conversion efficacy for selective methane synthesis in comparison with previous investigations.

Surface hydroxyl dependent adsorption of ruthenium on SiO2(0 0 1) – Understanding metal–support interaction

To understand the metal–support interaction of oxide supported transition metal catalysts, we computed the adsorption structures and energies of ruthenium on the idealized SiO2(001) surfaces with full (OH, 100%), partial (OH, 50%) surface hydroxyl and without surface hydroxyl (OH, 0%) at different ruthenium loading. On the fully (up to 9Ru) and partially (up to 6Ru) hydroxylated surfaces, ruthenium adsorption prefers surface O-H oxidative addition and forms regularly distributed Ru(H)2 species. After the reductive and re-combinative desorption of H2, the adsorbed ruthenium atoms prefer structures with aggregated 2Ru dimeric units on the fully hydroxylated surface, while structures of remote and dispersed singly adsorbed Ru atoms on the partially hydroxylated surface. On the hydroxyl free surface (up to 6Ru), the adsorbed ruthenium atoms prefer three-dimensional aggregated structures, which become more stable with the increase of ruthenium loading. This indicates the surface hydroxyl dependent ruthenium adsorption on SiO2 (001), and this finding is important for understanding the structure, stability and activity of silica supported ruthenium catalysts and catalysis.

Enhanced performance of Nb2O5 decorated RuO2/Sn0.2Ti0.8O2 for selective catalytic oxidation of ammonia

The ammonia slip from denitration system can result in environmental damage. Selective catalytic oxidation of ammonia (NH3-SCO) to nitrogen is one of the ideal technologies to control NH3 emission. In this work, RuO2/Sn0.2Ti0.8O2 catalysts with different Ru content and modified with Sb or Nb were evaluated for NH3-SCO. The results indicated that the RuO2&Nb2O5/Sn0.2Ti0.8O2 exhibited the similar catalytic activity and superior N2 selectivity within a wide temperature range in NH3-SCO, in comparison with RuO2/Sn0.2Ti0.8O2 and RuO2&Sb2O5/Sn0.2Ti0.8O2. Multiple techniques were used to reveal the effect of the physicochemical properties of the catalysts on the catalytic activity and N2 selectivity. For RuO2/Sn0.2Ti0.8O2, with the increasing ruthenium loading the activity enhanced together with the decline in N2 selectivity due to the high redox ability of highly dispersed ruthenium and the lack of acid sites. Particularly, in situ DRIFTS and NH3-TPD demonstrated the addition of Nb2O5 increased the quantity of acid sites, especially the Brønsted acid sites that were essential to improve N2 selectivity. During NH3 oxidation, the Brønsted acid sites promoted the activation of adsorbed ammonia to produce abundant amide intermediates (-NH2), which could directly react with the NO species to generate N2.

Hydrogenation of Ethylbenzene Over Ru/γ-Al₂O₃ Catalyst in Trickle-Bed Reactor.

The objective of this study is to evaluate the catalytic performance of pellet-type Ru/γ-Al₂O₃ as a catalyst during liquid-phase hydrogenation of the aromatic hydrocarbon. The Ru/γ-Al₂O₃ catalyst was prepared using a wet impregnation method. After adding a binder to Ru/γ-Al₂O₃, a pellet-type catalyst was obtained through an extrusion method. Nanoporous structures are well developed in the pellet-type Ru/γ-Al₂O₃ catalyst. The average pore sizes of the Ru/γ-Al₂O₃ catalysts were approximately 10 nm. The catalytic performance of the pellet-type Ru/γ-Al₂O₃ catalyst during ethylbenzene hydrogenation was evaluated in a trickle-bed reactor. When the ruthenium loading increased from 1 to 5 wt%, the number of active sites effective for the hydrogenation of ethylbenzene increased proportionally. In order to maximize the conversion of ethylbenzene to ethylcyclohexane, it was necessary to maintain a liquid phase hydrogenation reaction in the trickle bed reactor. In this regards, the reaction temperature should be lower than 90 °C. The conversion of ethylbenzene to ethylcyclohexane on the Ru(5 wt%)/γ-Al₂O₃ catalyst was highest, which is ascribed to the largest number of active sites of the catalyst.

Ultralow Loading Ruthenium on Alumina Monoliths for Facile, Highly Recyclable Reduction of p-Nitrophenol

The pervasive use of toxic nitroaromatics in industrial processes and their prevalence in industrial effluent has motivated the development of remediation strategies, among which is their catalytic reduction to the less toxic and synthetically useful aniline derivatives. While this area of research has a rich history with innumerable examples of active catalysts, the majority of systems rely on expensive precious metals and are submicron- or even a few-nanometer-sized colloidal particles. Such systems provide invaluable academic insight but are unsuitable for practical application. Herein, we report the fabrication of catalysts based on ultralow loading of the semiprecious metal ruthenium on 2–4 mm diameter spherical alumina monoliths. Ruthenium loading is achieved by atomic layer deposition (ALD) and catalytic activity is benchmarked using the ubiquitous para-nitrophenol, NaBH4 aqueous reduction protocol. Recyclability testing points to a very robust catalyst system with intrinsic ease of handling.

One-pot conversion of levulinic acid into gamma-valerolactone over a stable Ru tungstosphosphoric acid catalyst

In this paper ruthenium exchanged tungstophosphoric acid (TPA) catalysts with different ruthenium loading (RuxTPA (x = 1,2,3)) were studied for conversion of levulinic acid (LA) into gamma-valerolactone (GVL) (a potential fuel/fuel additive). Studies were also conducted on a Ru/C catalyst as Ru/C catalysts have recently been reported to have significant promise for this reaction. Under the conditions used (130 °C, 1.0 MPa H2, 2 h in 1,4 dioxane solvent) one of the prepared catalysts achieved excellent conversion and selectivity to GVL. This catalyst also compared favorably to Ru/C catalysts that have been previously studied in terms of rate of production of GVL per gram Ru. Characterization studies showed that Ru metal surface area and extent of Lewis and Brønsted acidity were characteristics that had a significant influence on the conversion and selectivity of the RuxTPA catalysts studied. The best performing Ru3TPA catalyst was found to be highly recyclable with only a slight decrease in selectivity of GVL (from 100% to 98.3%) being observed after five cycles of testing.

Selectivity engineering in catalysis by ruthenium nanoparticles supported on heteropolyacid-encapsulated MOF-5: one-pot synthesis of allyl 4-cyclohexanebutyrate and kinetic modeling

Functionalized metal-organic framework containing a heteropolyacid such as dodecatungstophosphoric (DTP)-encapsulated MOF-5 was synthesized by an in situ method and then ruthenium was incorporated by incipient wetness impregnation. A multifunctional heterogeneous catalyst, 1% Ru-15%DTP@MOF-5 with active acid and the metal sites make it the most efficient catalyst. For acid sites, dodecatungstophosphoric acid (DTP) was encapsulated into MOF-5 and ruthenium was loaded as metal sites. Its activity was examined in the one-pot synthesis of allyl 4-cyclohexanebutyrate, a flavoring agent, by esterification of 4-phenylbutyric acid with allyl alcohol followed by aromatic ring hydrogenation using molecular hydrogen. Esterification of 4-phenylbutyric acid with allyl alcohol gives allyl 4-phenylbutyrate which is further hydrogenated to give allyl 4-cyclohexanebutyrate. The octahedral cubic morphology of MOF-5 was retained even after DTP encapsulation and loading of ruthenium. Catalyst screening for esterification step was carried out by varying loadings of DTP (10, 15, and 20%) on MOF-5. Among these, 15% DTP-loaded MOF-5 showed the best catalytic activity. For selective aromatic ring hydrogenation, different metals such as Pd, Re, Ru, and Rh were examined and it was found that the Ru-based catalyst resulted in the highest conversion of allyl 4-phenylbutyrate (89.63%) and selectivity for allyl 4-cyclohexanebutyrate (96.52%). 1% Ru-15% DTP@MOF-5 catalyst was thermally stable and five times reusable. For both the steps, the kinetics was studied using the Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism and the apparent activation energy for esterification was calculated as 13.34 kcal/mol and that for hydrogenation as 14.87 kcal/mol.

Ultralow ruthenium loading Cobalt-molybdenum binary alloy as highly efficient and super-stable electrocatalyst for water splitting

Searching for earth-abundant, highly efficient, and stable bifunctional electrocatalysts for water splitting is critical for the further development of sustainable energy generation, yet it remains a great challenge. Herein, a facile electrodeposition strategy followed by wet-chemistry treatment is reported for the fabrication of the ultralow amount loading of ruthenium (Ru) on CoMo alloy supported on carbon fiber paper (CFP) substrate (Ru-CoMo/CFP). Benefiting from the unique nano-architectures and synergetic effect of loading Ru material and CoMo alloy, the optimized Ru-CoMo/CFP exhibits excellent electrocatalytic activity and favourable stability toward electrochemical water splitting. The as-prepared Ru-CoMo/CFP composite exhibits a current density of 10 mA·cm−2 at overpotentials of 44 and 237 mV for catalyzing hydrogen and oxygen evolution reaction (HER/OER) in alkaline medium, respectively. The as-synthetized Ru-CoMo/CFP electrode is also demonstrated to function as anode and cathode, simultaneously, only needs a cell voltage of 1.54 V to yield 10 mA·cm−2, outperforming the state-of-the-art RuO2||Pt/C couple (1.56 V). This work demonstrates substantial improvement in the design of high-efficiency electrodes for water electrolysis.

Encapsulation of a Ru(II) Polypyridyl Complex into Polylactide Nanoparticles for Antimicrobial Photodynamic Therapy.

Antimicrobial photodynamic therapy (aPDT) also known as photodynamic inactivation (PDI) is a promising strategy to eradicate pathogenic microorganisms such as Gram-positive and Gram-negative bacteria. This therapy relies on the use of a molecule called photosensitizer capable of generating, from molecular oxygen, reactive oxygen species including singlet oxygen under light irradiation to induce bacteria inactivation. Ru(II) polypyridyl complexes can be considered as potential photosensitizers for aPDT/PDI. However, to allow efficient treatment, they must be able to penetrate bacteria. This can be promoted by using nanoparticles. In this work, ruthenium-polylactide (RuPLA) nanoconjugates with different tacticities and molecular weights were prepared from a Ru(II) polypyridyl complex, RuOH. Narrowly-dispersed nanoparticles with high ruthenium loadings (up to 53%) and an intensity-average diameter < 300 nm were obtained by nanoprecipitation, as characterized by dynamic light scattering (DLS). Their phototoxicity effect was evaluated on four bacterial strains (Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli and Pseudomonas aeruginosa) and compared to the parent compound RuOH. RuOH and the nanoparticles were found to be non-active towards Gram-negative bacterial strains. However, depending on the tacticity and molecular weight of the RuPLA nanoconjugates, differences in photobactericidal activity on Gram-positive bacterial strains have been evidenced whereas RuOH remained non active.

Interface Engineering with Ultralow Ruthenium Loading for Efficient Water Splitting.

Developing high-performance and cost-effective bifunctional electrocatalysts for water splitting is the key to large-scale hydrogen production. How to achieve higher performance with a lower amount of noble metal is still a major challenge. Herein, using a facile wet-chemistry strategy, we report the ultralow amount loading of ruthenium (Ru) on porous nickel foam (NF) as a highly efficient bifunctional electrocatalyst for water splitting. Theoretical simulations reveal that the coupling effect of Ru and Ni can significantly reduce the d-band center of the composite. The Ru-modified NF exhibits a very high level of HER activity with only 0.3 wt% of Ru, far surpassing commercial Pt/C. It only requires an extremely low overpotential (η10) of 10 mV to achieve a current density of 10 mA cm-2 in alkaline solution and a quite low Tafel slope of 34 mV dec-1. This catalyst also shows remarkable performance for overall water splitting with a low voltage of 1.56 V at 10 mA cm-2. These findings indicate the potential of this material in water-alkali electrolyzers, providing a new approach for fabrication of low-cost advanced electrocatalysts.