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LiNbRu2 crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two LiNbRu2 ribbons oriented in the (1, 0, 0) direction. Li is bonded in a linear geometry to two equivalent Ru atoms. Both Li–Ru bond lengths are 2.71 Å. Nb is bonded in a linear geometry to two equivalent Ru atoms. Both Nb–Ru bond lengths are 2.18 Å. Ru is bonded in a linear geometry to one Li and one Nb atom.
Pr3Ru4Ge13 crystallizes in the cubic Pm-3n space group. The structure is three-dimensional. Pr is bonded in a 12-coordinate geometry to four equivalent Ru and twelve equivalent Ge atoms. All Pr–Ru bond lengths are 3.24 Å. There are eight shorter (3.25 Å) and four longer (3.27 Å) Pr–Ge bond lengths. Ru is bonded in a 6-coordinate geometry to three equivalent Pr and six equivalent Ge atoms. All Ru–Ge bond lengths are 2.51 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 2-coordinate geometry to three equivalent Pr, two equivalent Ru, and one Ge atom. The Ge–Ge bond length is 3.03 Å. In the second Ge site, Ge is bonded in a cuboctahedral geometry to twelve equivalent Ge atoms.
Ru2ZrSb crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two Ru2ZrSb ribbons oriented in the (1, 0, 0) direction. Zr is bonded in a linear geometry to two equivalent Ru atoms. Both Zr–Ru bond lengths are 2.24 Å. Ru is bonded in a linear geometry to one Zr and one Sb atom. The Ru–Sb bond length is 2.51 Å. Sb is bonded in a linear geometry to two equivalent Ru atoms.
Be2MnRu is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Be is bonded in a body-centered cubic geometry to four equivalent Mn and four equivalent Ru atoms. All Be–Mn bond lengths are 2.40 Å. All Be–Ru bond lengths are 2.40 Å. Mn is bonded in a 8-coordinate geometry to eight equivalent Be and six equivalent Ru atoms. All Mn–Ru bond lengths are 2.77 Å. Ru is bonded in a distorted body-centered cubic geometry to eight equivalent Be and six equivalent Mn atoms.
ZrTaRu2 crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two ZrTaRu2 ribbons oriented in the (1, 0, 0) direction. Zr is bonded in a linear geometry to two equivalent Ru atoms. Both Zr–Ru bond lengths are 2.31 Å. Ta is bonded in a linear geometry to two equivalent Ru atoms. Both Ta–Ru bond lengths are 2.21 Å. Ru is bonded in a linear geometry to one Zr and one Ta atom.
NbRu2Sn is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Nb is bonded in a body-centered cubic geometry to eight equivalent Ru atoms. All Nb–Ru bond lengths are 2.77 Å. Ru is bonded in a body-centered cubic geometry to four equivalent Nb and four equivalent Sn atoms. All Ru–Sn bond lengths are 2.77 Å. Sn is bonded in a distorted body-centered cubic geometry to eight equivalent Ru atoms.
HfZrRu2 crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two HfZrRu2 ribbons oriented in the (1, 0, 0) direction. Hf is bonded in a linear geometry to two equivalent Ru atoms. Both Hf–Ru bond lengths are 2.30 Å. Zr is bonded in a linear geometry to two equivalent Ru atoms. Both Zr–Ru bond lengths are 2.28 Å. Ru is bonded in a linear geometry to one Hf and one Zr atom.
Yb3Ru4Ge13 crystallizes in the cubic Pm-3n space group. The structure is three-dimensional. Yb is bonded in a 8-coordinate geometry to four equivalent Ru and twelve equivalent Ge atoms. All Yb–Ru bond lengths are 3.19 Å. There are eight shorter (3.13 Å) and four longer (3.22 Å) Yb–Ge bond lengths. Ru is bonded in a 9-coordinate geometry to three equivalent Yb and six equivalent Ge atoms. All Ru–Ge bond lengths are 2.50 Å. There are two inequivalent Ge sites. In the first Ge site, Ge is bonded in a 6-coordinate geometry to three equivalent Yb, two equivalent Ru, and two Ge atoms. There are one shorter (2.68 Å) and one longer (3.11 Å) Ge–Ge bond lengths. In the second Ge site, Ge is bonded in a cuboctahedral geometry to twelve equivalent Ge atoms.
TiVRu2 crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two TiVRu2 ribbons oriented in the (1, 0, 0) direction. Ti is bonded in a linear geometry to two equivalent Ru atoms. Both Ti–Ru bond lengths are 2.17 Å. V is bonded in a linear geometry to two equivalent Ru atoms. Both V–Ru bond lengths are 2.12 Å. Ru is bonded in a linear geometry to one Ti and one V atom.
WRu2Al crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two WRu2Al ribbons oriented in the (1, 0, 0) direction. W is bonded in a linear geometry to two equivalent Ru atoms. Both W–Ru bond lengths are 2.13 Å. Ru is bonded in a linear geometry to one W and one Al atom. The Ru–Al bond length is 2.51 Å. Al is bonded in a linear geometry to two equivalent Ru atoms.
La3Ru4Sn13 crystallizes in the cubic Pm-3n space group. The structure is three-dimensional. La is bonded in a 12-coordinate geometry to four equivalent Ru and twelve equivalent Sn atoms. All La–Ru bond lengths are 3.49 Å. There are four shorter (3.45 Å) and eight longer (3.50 Å) La–Sn bond lengths. Ru is bonded in a 6-coordinate geometry to three equivalent La and six equivalent Sn atoms. All Ru–Sn bond lengths are 2.69 Å. There are two inequivalent Sn sites. In the first Sn site, Sn is bonded in a 2-coordinate geometry to three equivalent La, two equivalent Ru, and one Sn atom. The Sn–Sn bond length is 3.35 Å. In the second Sn site, Sn is bonded in a cuboctahedral geometry to twelve equivalent Sn atoms.
TaRu2Ge crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two TaRu2Ge ribbons oriented in the (1, 0, 0) direction. Ta is bonded in a linear geometry to two equivalent Ru atoms. Both Ta–Ru bond lengths are 2.18 Å. Ru is bonded in a linear geometry to one Ta and one Ge atom. The Ru–Ge bond length is 2.37 Å. Ge is bonded in a linear geometry to two equivalent Ru atoms.
Ru2AlSn crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two Ru2AlSn ribbons oriented in the (1, 0, 0) direction. Ru is bonded in a linear geometry to one Al and one Sn atom. The Ru–Al bond length is 2.43 Å. The Ru–Sn bond length is 2.56 Å. Al is bonded in a linear geometry to two equivalent Ru atoms. Sn is bonded in a linear geometry to two equivalent Ru atoms.
RuNiGa2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ru is bonded in a body-centered cubic geometry to six equivalent Ni and eight equivalent Ga atoms. All Ru–Ni bond lengths are 2.98 Å. All Ru–Ga bond lengths are 2.58 Å. Ni is bonded in a distorted body-centered cubic geometry to six equivalent Ru and eight equivalent Ga atoms. All Ni–Ga bond lengths are 2.58 Å. Ga is bonded in a body-centered cubic geometry to four equivalent Ru and four equivalent Ni atoms.
Abstract The organic ligand environment surrounding enzymatic and homogeneous catalytic active sites often determines catalytic activity. Ruthenium nanoparticles, ≤1 nm in diameter, are synthesized using monodentate thiol, monodentate phosphine, and bidentate bisphosphine ligands. Even though some of the ruthenium surface is blocked by the ligands, catalytic activity is still observed for CO oxidation and H 2 O 2 decomposition. All three ligand‐stabilized ruthenium nanoparticles have similar CO oxidation rates; however, the bisphosphine‐stabilized Ru nanoparticles are approximately 2.5 times less active than the monothiol‐stabilized and monophosphine‐stabilized ruthenium nanoparticles for H 2 O 2 decomposition. It is observed that the organic ligand environment is modulated in situ during nanoparticle synthesis via partial oxidation of the bisphosphine as confirmed by 31 P NMR measurements. We hypothesize that bisphosphine‐bound Ru nanoparticles consist of a Ru core with some of the ligands bound in a monodentate manner where the other P atom is oxidized and not bound to the Ru surface leading to a thicker hydrophobic layer around the Ru nanoparticles. The increase in hydrophobicity is confirmed via contact angle and zeta potential measurements. H 2 O 2 decomposition rates are known to decrease with increasing hydrophobicity, and this work illustrates a pathway for increasing hydrophobicity in situ using ligand‐bound metallic nanoparticles.
Ruthenium has emerged as a promising substitute for platinum toward the hydrogen evolution/oxidation reaction (HER/HOR). Herein, ruthenium/carbon composites are prepared by magnetic induction heating (300 A, 10 s) of RuCl3, RuBr3 or RuI3 loaded on hollow N-doped carbon cages (HNC). The HNC-RuCl3-300A sample consists of Ru nanoparticles (dia. 1.96 nm) and abundant Cl residues. HNC-RuBr3-300A possesses a larger nanoparticle size (≈19.36 nm) and lower content of Br residues. HNC-RuI3-300A contains only bulk-like Ru agglomerates with a minimal amount of I residues, due to reduced Ru-halide bonding interactions. Among these, HNC-RuCl3-300A exhibits the best HER activity in alkaline media, with a low overpotential of only -26 mV to reach 10 mA cm-2, even outperforming Pt/C, and can be used as the cathode catalyst for anion exchange membrane water electrolyzer (along with commercial RuO2 as the anode catalyst), producing 0.5 A cm- 2 at 1.88 V for up to 100 h, a performance markedly better than that with Pt/C. HNC-RuCl3-300A also exhibits the best HOR activity, with a half-wave potential (+18 mV) even lower than that of Pt/C (+35 mV). These activities are ascribed to the combined contributions of small Ru nanoparticles and Ru-to-halide charge transfer that weaken H adsorption.
This communication describes the investigation of a coordinatively saturated complex [Ru(tpy)(dmabpy)Cl] + ([Ru(Cl)] + ) as an ammonia oxidation catalyst. Cyclic voltammetry measurements show an ideal S-shaped wave, indicating total catalysis conditions with a k obs (TOF max ) of 9360 h −1 . The reaction was found to be first-order in [Ru(Cl)] + and third-order in [NH 3 ]. Stoichiometric reactions of the one-electron oxidized species, [Ru(Cl)] 2+ , were monitored following the addition of 15 NH 3 using 1 H and 15 N NMR spectroscopy. These experiments showed that the chloride-coordinated complex rapidly converts NH 3 to N 2 . NMR spectroscopy and electrochemistry results definitively show that NH 3 does not substitute the Cl − ligand to form the previously reported [Ru(NH 3 )] 2+ catalyst which operates by a different mechanistic pathway. Taken together these results indicate outersphere electron transfer mediated ammonia oxidation reaction.
Catalyst design has traditionally focused on tuning active site properties to optimally bind reaction intermediates and balance the kinetic requirements of multiple competing chemical processes, as necessitated by the Sabatier principle. It has recently been proposed that for reactions following certain potential energy landscapes, the activity limit imposed by the Sabatier principle may be overcome by using programmed oscillations of surface electron density at the timescales of surface reactions (i.e., “catalytic resonance”). Here, we use a combination of density functional theory (DFT) simulations and transient kinetic models (TKMs) to simulate the kinetics of steam methane reforming (SMR) on Ru(211) surfaces under statically and dynamically applied charges. DFT-calculated binding energies of SMR intermediates and transition states exhibit strong sensitivity to positively applied charges and follow unique scaling relationships that deviate from linear periodic trends across transition metals. Our simulations demonstrate that applying a small positive charge to Ru dramatically enhances the steady-state turnover frequency (TOF) of SMR by up to 5 orders of magnitude above the TOF observed over neutral Ru. Thus, statically charging Ru catalysts may be an effective strategy to lower the temperature requirements for SMR. Dynamic square-wave oscillations in charge resulted in SMR catalytic resonance with an onset frequency f ∼ 106 Hz and the corresponding average TOFs exceeding the statically charged Ru surface by an additional 15%. Here, based on sensitivity analyses performed for the two end points of oscillation, we propose that dynamic TOF improvement beyond the Sabatier maximum can be expected when the system oscillates between two kinetic regimes that are uniquely controlled by distinct elementary steps.