Platinum Metals Rev., 2010, 54, (4), 263
PATENTS: October 2010
CATALYSIS – APPLIED AND PHYSICAL ASPECTS
Clean Production of Solid Ruthenium Complex
Johnson Matthey PLC, World Appl. 2010/064,045
A cationic Ru complex is produced by reacting a [Ru(arene)(halogen)2]2 with a 4,4'-bis(disubstitutedphosphino)-3,3'-bipyridine ligand in at least one alcohol with boiling point <120°C at 1 atm. Preferred arenes are benzene, p-cymene or 1,3,5-trimethylbenzene; halogens are Cl, Br or I and ligands are PPhos, TolPPhos and XylPPhos. The complex may be used as a hydrogenation catalyst without solvent change. Further, a C1–10 alkane may be added to produce a solid complex, which exhibits improved stability over complexes precipitated with solvents such as MBTE.
Hydrothermally-Prepared Rhodium on Zeolite
Nippon Chem. Ind. Co, Ltd, Japanese Appl. 2010-029,787
A hydrothermal method for producing a catalyst with >1 wt% Rh highly dispersed on zeolite is claimed. An aqueous slurry of a high-silica zeolite; a water-soluble Rh salt, preferably Rh(III) nitrate; and a source of either tetraethylammonium or tetrapropylammonium as a templating agent, preferably tetraethylammonium hydroxide, is prepared. The molar ratio of water, Rh and templating agent is 1–50:0.001–0.03:0.01–1, based on Si in the zeolite. The mixture, with pH 10–14, is then treated at 140–180°C for ~40–70 h.
CATALYSIS – INDUSTRIAL PROCESS
PGM Catalyst for Upgrading Middle Distillates
Total Raffinage Marketing SA, World Appl. 2010/079,044
A feedstock such as light cycle oil with CI ≤40, CN ≤35, 100 ppm ≤ N ≤1200 ppm, 200 ppm ≤ S ≤ 2.5 wt% and aromatics ≥50 wt%, is in a first step passed over an HDS/HDN catalyst such as NiMo/Al2O3. The effluent, optionally stripped, is then hydrodearomatised over a catalyst containing 0.25–1 wt% of each of Pt and Pd highly dispersed on a SiO2–Al2O3 carrier with a pore volume of 0.6 ml g−1 and a surface area of 300 m2 g−1. Reaction conditions are typically 0.5–1.2 h−1 LHSV, 250–320°C and 45–65 bar gauge pressure. The product obtained may have S ≤1 ppm, N ≤1 ppm, aromatics ≤2 wt%, 35 ≤ CI ≤ 43 and 40 ≤ CN ≤ 48, and is suitable for use in a diesel pool at ≥50 wt%.
CATALYSIS – REACTIONS
Phosphorus-Free Rhodium Hydrogenation Catalyst
Schlumberger Technol. Corp, US Appl. 2010/0,168,454
Hydrogenation of C=C or C=N bonds in organic compounds is carried out in the presence of a Rh complex with non-phosphine ligands A and B, where A is a heterocyclic organic base, 1, preferably 1a and particularly 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), 1b, or 1,5-diazabicyclo[5.3.0]non-5-ene (DBN), 1c, and B is a cycloaliphatic diene, preferably 1,5-cyclooctadiene (COD).
Three-Way Catalyst with Improved Sulfur Tolerance
Toyota Central Res. Dev. Labs Inc, Japanese Appl. 2010-051,847
A dual-layer catalyst has: a first layer with 0.01–5 wt% Pt supported on CeO2–ZrO2 (≥45 wt% CeO2) and Al2O3 (≤0.1 wt% TiO2); and a second layer with 0.01–5 wt% Rh supported on CeO2–ZrO2 (4–35 wt% CeO2) and TiO2–Al2O3 (5–20 wt% TiO2). This formulation of the compound oxides is found to control S poisoning to limit formation of H2S and further prevents degradation of OSC performance during high-temperature operation.
Catalyst for Removal of CO from Motorcycle Exhaust
Cataler Corp, Japanese Appl. 2010-058,069
A catalyst suitable for low-temperature use in motorcycles consists of a honeycomb substrate with two sections. The first stage has loadings (per litre substrate): 1–10 g Pd, preferably 2.5–6 g Pd; and 0.05–5 g Rh, preferably 0.15–1.5 g Rh. The second, downstream stage has loadings (per litre substrate): 0 g Pd and 0.05–5 g Rh, preferably 0.15–1.5 g Rh. The Pd in the first stage acts to raise the temperature of the exhaust gas, promoting oxidation of CO in the second stage, even under rich exhaust conditions.
Quarternary Fuel Cell Catalyst
UTC Power Corp, World Appl. 2010/050,964
An alloy has composition PtwVxMyIrz, where (in mol%): 30 ≤ w ≤ 75,5 ≤ x ≤ 50,5 ≤ y ≤ 50 and 5 ≤ z ≤ 30, and M is one or a combination of Co, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Mo and W. Specifically, the alloy is Pt40V20Co30Ir10 and is deposited at 10–70 wt% loading on a C support as particles 2–20 nm in size. As a cathode catalyst in a PEMFC, PAFC, SOFC or other fuel cell, the alloy is durable and has high ORR activity.
Platinum Mesh for Strengthening SOFC
Shinko Electr. Ind. Co, Ltd, US Patent 7,722,980 (2010)
A SOFC system has a cathode electrode layer and an anode electrode layer formed on opposite faces of a single solid oxide substrate, with both layers containing an embedded Pt mesh and the whole encased in an oxide layer formed from a solid electrolyte. The Pt mesh and oxide layer prevent cracking of the cell due to thermal shock, allowing the system to be heated by direct exposure to a flame with rapid start-up. The Pt meshes may also be connected to lead wires and function as current-collecting electrodes.
METALLURGY AND MATERIALS
Multilayer Coating for Costume Jewellery
Umicore Galvanotechnik GmbH, World Appl. 2010/057,573
A base metal blank is successively plated with: (a) an optional first layer of 15–20 μm Cu; (b) a 1–3 μm layer of preferably pure Pd; (c) an optional intermediate layer of 0.1–0.2 μm Au; and (d) a 0.1–0.5 μm layer of either Pt-Ru with 60–75 wt% Pt, or Rh-Ru with 70–80 wt% Rh. Layers (b) and (d) are preferably deposited by rack coating. The coating is found to have abrasion resistance which is much higher than the average resistance of the metals in (d). Good colour and brightness are also obtained.
Rhodium Alloy for Gas Turbine Repair
General Electric Co, US Patent 7,722,729 (2010)
An alloy with improved high-temperature performance is composed of (in at%): (a) ≥50% Rh; (b) ≤49% of one of Pt, Pd, Ir (or a combination); (c) 1–15%, preferably 1–6%, W and/or Re; (d) ≤10%, preferably ≤8%, Ru and/or Cr; and, optionally (e) ≤3%, preferably ≤2%, one or more of Zr, Y, Hf,Ta, Al, Ti, Sc, a lanthanide and an actinide. The sum of (a) and (b) is ≥75%, preferably ≥85%. The alloy contains ≥90 vol% of the A1-structured phase at >1000°C. A method of using the alloy to repair components such as the blade tip, leading and trailing edges is also claimed.
Low-Melting Palladium Solder
K. Weinstein, US Patent 7,722,806 (2010)
A solder for use with Ni-free white Au and Pd jewellery consists of 85–95 wt% Pd and the balance a mixture of Ga and In in a weight ratio of ~7:3, with the composition tuned to attain the desired hardness for each application. When used with white Au, the solder may contain the carated amount of Au with the balance a mixture of Pd, Ag, Cu, Zn, Ga and In. The solder melts at ~1200–1300°C, making it particularly suitable for repair and resizing of Au and Pd jewellery.
ELECTRICAL AND ELECTRONICS
Nanoelectromechanical Switch with Ruthenium Beam
Sandia Corp, US Patent 7,719,318 (2010)
A NEM switch is formed on a Si substrate by: suspending a beam of Ru between two anchor points to form the source electrode, 1; positioning one drain electrode, 2, or a pair thereof at the midpoint of the beam but laterally offset by a 20–75 nm gap; positioning one or two pairs of electrically-connected gate electrodes, 3, around the midpoint of the beam but offset by a 30–100 nm gap. The Ru beam is ≤10 μm long and ≤0.1 μm wide and bows laterally towards 2 in response to an actuation voltage applied across 1 and 3, thus forming a connection between 1 and 2. A RuO2 coating can be applied to 1 to prevent fouling of contact surfaces. The switch can be used to form fast-response NAND and NOR gates or SRAM and DRAM memory cells.
Plasma Display Panels Containing Palladium
Panasonic Corp, Japanese Appl. 2010-049,817
A finely-grained pgm powder is included in non-emitting gaps between the front and rear substrates of a plasma display panel, either in the phosphor layer or on the protective layer. The pgm is preferably Pd or Pd alloyed with a transition metal such as Ti, Mn, Zr, Ni, Co, La, Fe or V, and absorbs H2 released by minor amounts of H2O and HCs trapped in the panel during construction. It thereby prevents deterioration of the display which occurs over time as the active components react with these contaminants.
Improved Anode Catalyst for Chlor-Alkali Cell
Industrie De Nora SpA, World Appl. 2010/055,065
An anode has a catalyst layer comprising oxides of Sn, Ru, Ir, Pd and Nb in a molar proportion (based on element) of: 50–70% Sn, 5–20% Ru, 5–20% Ir, 1–10% Pd and 0.5–5% Nb. It is deposited on a valve metal substrate such as Ti or Ti alloy by a multi-coat application of a precursor solution, preferably containing hydroxyacetyl chloride complexes of Ru, Ir or Sn; Pd(NO3)2 in HNO3(aq) or PdCl2 in EtOH; and NbCl5 in BuOH, followed by heat treatment at 400–480°C for 15–30 minutes. The catalyst is highly active for the Cl2 evolution reaction while maintaining a high overvoltage for O2 evolution, giving improved cell efficiency.
Iridium-Doped Oxygen Evolution Catalyst
California Institute of Technology, World Appl. 2010/045,483
An O2 evolution catalyst is prepared from a mixture of powders of RuO2 and a doping metal, M, either Ir or Pb, which is heated at a temperature below the sintering temperatures of both powders so that M is partially oxidised by the RuO2 to produce MOxRuO2–x where x = ~0.05. M may also be present in the catalyst at 5–25 at%, preferably 9–12 at%. The doped Ru oxide catalyst is found to be stable in acidic media and is suitable for use in the anodic oxidation of H2O in a PEM-based electrolyser.
MEDICAL AND DENTAL
Palladium Coating for Biodegradable Stent
Biotronik SE & Co KG, US Appl. 2010/0,161,053
A Pd coating is electrolytically or galvanically applied to an intraluminal endoprosthesis consisting of or containing a biodegradable material, particularly Mg, which releases H2 as a reaction product while degrading. The Pd layer is preferably 90–100 wt% pure and 2–6 μm thick, with a particle size range of 50–500 nm. It controls the release of H2 from the stent, so slowing degradation to the desired rate.