Heterometal nanoparticles from Ru-based molecular clusters covalently anchored onto functionalized carbon nanotubes and nanofibers

Abstract

SummaryHeterometal clusters containing Ru and Au, Co and/or Pt are anchored onto carbon nanotubes and nanofibers functionalized with chelating phosphine groups. The cluster anchoring yield is related to the amount of phosphine groups available on the nanocarbon surface. The ligands of the anchored molecular species are then removed by gentle thermal treatment in order to form nanoparticles. In the case of Au-containing clusters, removal of gold atoms from the clusters and agglomeration leads to a bimodal distribution of nanoparticles at the nanocarbon surface. In the case of Ru–Pt species, anchoring occurs without reorganization through a ligand exchange mechanism. After thermal treatment, ultrasmall (1–3 nm) bimetal Ru–Pt nanoparticles are formed on the surface of the nanocarbons. Characterization by high resolution transmission electron microscopy (HRTEM) and high angle annular dark field scanning transmission electron microscopy (HAADF-STEM) confirms their bimetal nature on the nanoscale. The obtained bimetal nanoparticles supported on nanocarbon were tested as catalysts in ammonia synthesis and are shown to be active at low temperature and atmospheric pressure with very low Ru loading.

Molecular Nickel Phosphide Carbonyl Nanoclusters: Synthesis, Structure, and Electrochemistry of [Ni11P(CO)18]3–and [H6–nNi31P4(CO)39]n−(n= 4 and 5)

“…It has been pointed out that molecular metal nanoclusters might be interesting models for the investigation of metal aggregates at the nanolevel, as well as promising precursors for the preparation of metal nanoparticles and catalytic materials. − Thus, it is quite remarkable that molecular nickel phosphide nanoclusters have not been reported up to now. This should be contrasted with the tendency of Ni to form several molecular carbonyl clusters containing other fully interstitial p-block elements, such as C, Ga, Ge, Sn, and Sb. , Ni-carbide carbonyl clusters display a very rich chemistry and may contain 1–10 interstitial C atoms. − Conversely, heavier heteroatoms show a poorer chemistry.…”

pH controlled adsorption of water-soluble ruthenium clusters onto carbon nanotubes and nanofiber surfaces

“…It can be explained by the parallel walls and a higher specific surface area of the CNT solid, namely 305 m 2 g À1 , compared to LHT or LHT-OX, at 35 and 26 m 2 g À1 , respectively (Table S1 in ESI †). 52,56 This was suggested in other studies comparing the adsorption capacity of CNTs with other carbonaceous materials of lower specific surface areas 57,58 or CNF, 56,59 with CNTs in all cases being more efficient. The adsorption percentage drops as the pH decreases.…”

“…This precursor can be seen as a non-watersoluble equivalent of [Ru 5 C(CO) 10 (PTA) 5 ] and was already used as a nanoparticle precursor in the literature. 56,60 The sample prepared in dichloromethane contains 3 wt% Ru, which is the same metal loading as Ru5P/LHT. It was activated at 350 1C under the same conditions as the others.…”

Geometric Transformation of Modified Multiwalled Carbon Nanotubes-Based Heterometallic Nanostructured Material: A Model for the Electrochemical Discrimination of Insecticides

“…21 Moreover, materials containing heterometal having application in homogenous catalysis, electrocatalysis, excellent electrical conductivity had also been reported. 22,23 In particular, noncovalent immobilization of polyaromatic hydrocarbons such as the pyrene moiety on the sidewall of MWCNTs via π−π interactions was reported as a straightforward strategy. 24−26 The CNTs functionalized with small organic molecules or polymer-based molecules have been utilized for increasing the dispersibility as well as surface area of MWCNTs via π−π interactions, van der Waals interaction, and electrostatic interaction.…”

“…Therefore, modification of MWCNTs by different materials such as metal nanoparticles, metal oxides, and organic ligands tends to open up these bundles and make them dispersible in different solvents. − Song et al synthesized a hybrid containing FeCo bimetallic organic frameworks, a melamine mixture, and bamboo-like N-doped CNTs, entangled with N-doped carbon nanosheet nanocomposites (FexCoy–N–C), which shows an outstanding oxygen reduction reaction performance in alkaline medium by the synergistic effect . Moreover, materials containing heterometal having application in homogenous catalysis, electrocatalysis, excellent electrical conductivity had also been reported. , In particular, noncovalent immobilization of polyaromatic hydrocarbons such as the pyrene moiety on the sidewall of MWCNTs via π–π interactions was reported as a straightforward strategy. − The CNTs functionalized with small organic molecules or polymer-based molecules have been utilized for increasing the dispersibility as well as surface area of MWCNTs via π–π interactions, van der Waals interaction, and electrostatic interaction. − The modification mainly intensifies the conductivity of MWCNTs by providing more electron transfer and making it a more advantageous nanomaterial for electrochemical studies. , The modification of MWCNTs with heterocomplexes manipulates the properties of the combined material and provides an excellent electrochemical activity . Novel strategies for the development of new materials as well as improving the electrocatalytic activity and stability of current materials are greatly desired .…”