A comparative study on the performance of M (Rh,Ru, Ni)-promoted metallurgical waste driven catalysts for H2 production by glycerol steam reforming

A comprehensive study was conducted on the performance of M-promoted (M = 1%Ru, 1%Rh, 5%Ni) upgraded slag oxide metallurgical waste catalysts (M-UGSO) for hydrogen production by glycerol steam reforming (GSR). The results confirmed that the tendency of the incorporated metal to interact with Mg/Fe containing species within UGSO plays a key role in the surface availability of the corresponding metal, structural changes after reduction, and catalyst stability. Aside its best stability, 5% Ni-UGSO showed a performance (glycerol conversion to gaseous products of 100% and H₂ yield of 74%) comparable with 1% Rh-UGSO (100% and 78%, respectively) or even surpassing that of 1% Ru-UGSO (94% and 71%, respectively), as noble metal-based catalysts. Synergistic cooperation was achieved by incorporated metals (M) and Fe/Mg containing species within UGSO, resulting in enhanced glycerol and water activation. The weakest results of Ru-UGSO could be justified by lack of propensity for MgO–RuO₂ interaction on UGSO surface.     

Note of Caution for the Aqueous Behaviour of Metal-Based Drug Candidates

Poor aqueous solubility is one of the recurrent drawbacks of many compounds in medicinal chemistry. To overcome this limitation, the dilution of drug candidates from stock solutions of an organic solvent is common practice. However, the precise characterisation of these compounds in aqueous solutions is often neglected, leading to some uncertainties regarding the nature of the actual active species. In this communication, we demonstrate that two ruthenium complexes previously reported by our group for their chemotherapeutic potential against cancer, namely [Ru(DIP)₂(sq)](PF₆) and [Ru(DIP)₂(3-methoxysq)](PF₆), where DIP is 4,7-diphenyl-1,10-phenanthroline, sq=semiquinonate and 3-methoxysq=3-methoxysemiquinonate, form colloids in water-DMSO (1 % v/v) mixtures that are invisible to the naked eyes. [Ru(DIP)₂(3-methoxysq)](PF₆) was found to form a highly stable and monodispersed colloid with nanoaggregates of ∼25 nm. In contrast, [Ru(DIP)₂(sq)](PF₆) was found to form large reticulates of mostly spherical aggregates which size was found to increase over time. The difference in size and shape distribution of drug candidates is of tremendous significance as the study of their biological activity might be severely affected. Overall, we strongly believe that these observations should be taken into account by the scientific community working on the development of metal-based drugs with poor water solubility.     

Ruthenium(II)–Arene Thiocarboxylates: Identification of a Stable Dimer Selectively Cytotoxic to Invasive Breast Cancer Cells

Ru^II-arene complexes provide a versatile scaffold for novel anticancer drugs. Seven new Ru^II-arene-thiocarboxylato dimers were synthesized and characterized. Three of the complexes ( 2 a , b and 5 ) showed promising antiproliferative activities in MDA-MB-231 (human invasive breast cancer) cells, and were further tested in a panel of fifteen cancerous and noncancerous cell lines. Complex 5 showed moderate but remarkably selective activity in MDA-MB-231 cells (IC₅₀=39±4 μm Ru). Real-time proliferation studies showed that 5 induced apoptosis in MDA-MB-231 cells but had no effect in A549 (human lung cancer, epithelial) cells. By contrast, 2 a and b showed moderate antiproliferative activity, but no apoptosis, in either cell line. Selective cytotoxicity of 5 in aggressive, mesenchymal-like MDA-MB-231 cells over many common epithelial cancer cell lines (including noninvasive breast cancer MCF-7) makes it an attractive lead compound for the development of specifically antimetastatic Ru complexes with low systemic toxicity.     

Carbon supported bimetallic Ru‐Co catalysts for H2 production through NaBH4 and NH3BH3 hydrolysis

This work investigates the effect of the addition of small amounts of Ru (0.5‐1 wt%) to carbon supported Co (10 wt%) catalysts towards both NaBH₄ and NH₃BH₃ hydrolysis for H₂ production. In the sodium borohydride hydrolysis, the activity of Ru‐Co/carbon catalysts was sensibly higher than the sum of the activities of corresponding monometallic samples, whereas for the ammonia borane hydrolysis, the positive effect of Ru‐Co systems with regard to catalytic activity was less evident. The performances of Ru‐Co bimetallic catalysts correlated with the occurrence of an interaction between Ru and Co species resulting in the formation of smaller ruthenium and cobalt oxide particles with a more homogeneous dispersion on the carbon support. It was proposed that Ru^°, formed during the reduction step of the Ru‐Co catalysts, favors the H₂ activation, thus enhancing the reduction degree of the cobalt precursor and the number of Co nucleation centers. A subsequent reduction of cobalt and ruthenium species also occurs in the hydride reaction medium, and therefore the state of the catalyst before the catalytic experiment determines the state of the active phase formed in situ. The different relative reactivity of the Ru and Co active species towards the two investigated reactions accounted for the different behavior towards NaBH₄ and NH₃BH₃ hydrolysis.     

Sputtered Ir–Ru based catalysts for oxygen evolution reaction: Study of iridium effect on stability

Magnetron sputtered low-loading iridium-ruthenium thin films are investigated as catalysts for the Oxygen Evolution Reaction at the anode of the Proton Exchange Membrane Water Electrolyzer. Electrochemical performance of 50 nm thin catalysts (Ir pure, Ir–Ru 1:1, Ir–Ru 1:3, Ru pure) is tested in a Rotating Disk Electrode. Corresponding Tafel slopes are measured before and after the CV-based procedure to compare the activity and stability of prepared compounds. Calculated activities prior to the procedure confirm higher activity of ruthenium-containing catalysts (Ru pure > Ir–Ru 1:3 > Ir–Ru 1:1 > Ir pure). However, after the procedure a higher activity and less degradation of Ir–Ru 1:3 is observed, compared to Ir–Ru 1:1, i.e. the sample with a higher amount of unstable ruthenium performs better. This contradicts the expected behavior of the catalyst. The comprehensive chemical and structural analysis unravels that the stability of Ir–Ru 1:3 sample is connected to RuO₂ chemical state and hcp structure. Obtained results are confirmed by measuring current densities in a single cell.     

钛基钛钌铱三元氧化物涂层pH电极的研究

用涂敷技术制备了一种钛基钛钌铱三元氧化物涂层ｐＨ电极。由于在氧化钛涂层中加入了与氧化钛同属金红石晶型的电子导电型半导体化合物氧化钌和氧化铱，因此提高了反应的交换电流密度，有效地克服了用传统的电化学氧化或热氧化法制备的钛基ｐＨ电极的电极斜率低、响应速度慢的缺点，使制得的ｐＨ电极性能优良，可投入实际应用。     

含钌废催化剂回收钌的技术综述

从废钌催化剂中回收钌对于钌资源缺乏的我国具有特殊意义。基于文献和国内相关专利的分析,对氧化蒸馏法、熔融还原沉淀法、离子交换法、吸附法、捕集法、萃取法以及其他回收钌的方法进行了综述分析。不同方法各有其优缺点,其中成熟和应用最广的是氧化蒸馏法,选择性吸附法和萃取法具有选择性高、回收率高、污染小,是有发展前景的技术。     

钌基催化剂在加氢反应中的应用

钌基催化剂在低温和低压等温和条件下具有优异的催化性能,因而广泛应用于各种反应中。文章介绍了钌基催化剂的研究现状,着重探讨了其在加氢反应中的应用和研究进展,包括载体材料、前驱体和助剂对催化剂性能的影响。所涉及的反应包括:CO2加氢合成甲酸、CO/CO2甲烷化、苯加氢制环己烯、苯胺加氢制环己胺与二环己胺、多元醇加氢制备二元醇、葡萄糖加氢合成山梨醇等,并对它的应用前景进行了展望。