Platinum Metals Review: Most Recent Articles

Editorial: Platinum Metals Review: Looking Back and Moving Forward

SARA COLES — Tue, 01 Apr 2014 00:00:00 GMT

Recent Research and Developments Related to Near-Equiatomic Titanium-Platinum Alloys for High-Temperature Applications

By Abdul Wadood and Yoko Yamabe-Mitarai — Tue, 01 Apr 2014 00:00:00 GMT

Titanium-platinum (Ti50Pt50) (all compositions in at%) alloy exhibits thermoelastic martensitic phase transformation above 1000°C and has potential for high-temperature shape memory material applications. However, as has been previously reported, Ti50Pt50 alloy exhibited a negligible recovery ratio (0–11%) and low strength in martensite and especially in the austenite phase due to low critical stress for slip deformation. In order to improve the high-temperature strength and shape memory properties, the effects of partial substitution of Ti with other Group 4 elements such as zirconium and hafnium and the effect of partial substitution of Pt with other platinum group metals (pgms) such as iridium and ruthenium on the high-temperature mechanical and shape memory properties of Ti50Pt50 alloy were recently investigated. This paper reviews the transformation temperatures and high-temperature mechanical and shape memory properties of recently developed Ti site substituted (Ti,Zr)50Pt50, (Ti,Hf)50Pt50 and Pt site substituted Ti50(Pt,Ru)50 and Ti50(Pt,Ir)50 alloys for high-temperature (~800°C–1100°C) material applications.

Hydrogen and Fuel Cell Technologies at the Hydrogen South Africa (HySA) Systems Competence Centre

Tue, 01 Apr 2014 00:00:00 GMT

The Hydrogen South Africa (HySA) programme is based upon the beneficiation of South Africa’s large platinum group metal (pgm) resources. The present article summarises some of the progress by HySA Systems, one of the three Competence Centres under the HySA Programme, since 2008. Work has been carried out on membrane electrode assembly and stack development for high-temperature proton exchange membrane fuel cells (HT-PEMFCs) for use in combined heat and power (CHP) supplied by natural gas and hydrogen fuelled vehicle (HFV) applications. The emphasis is on improved carbon monoxide tolerance and simplified heat and humidity management, allowing simpler fuel cell systems to be designed. Metal hydrides modified with palladium are being explored as poisoning-tolerant hydrogen storage materials for stationary and special mobile applications, and metal organic frameworks (MOFs) modified with platinum as light-weight hydrogen storage with a high hydrogen storage capacity. Lastly research into hydrogen purification using Pd membrane reactors is focused on membrane support synthesis, hollow fibre seeding and development of the plating procedure.

Chernyaev 2013: XX International Chernyaev Conference on Chemistry, Analysis and Technology of Platinum Group Metals

Reviewed by Kirill V. Yusenko, Sergey I. Metelitsa and Vladimir N. Losev — Tue, 01 Apr 2014 00:00:00 GMT

Dennis Dowden Commemoration: Catalysis – from Fundamentals to Application

Reviewed by Martin Fowles — Tue, 01 Apr 2014 00:00:00 GMT

“Palladium-Catalyzed Coupling Reactions: Practical Aspects and Future Developments”

Reviewed by Robert Hanley — Tue, 01 Apr 2014 00:00:00 GMT

PGMs IN THE LAB: New Diphosphines for Molecular and Nanoparticle Catalysis

Tue, 01 Apr 2014 00:00:00 GMT

Johnson Matthey Highlights

Tue, 01 Apr 2014 00:00:00 GMT

FINAL ANALYSIS: Characterisation of Catalysts Using Secondary and Backscattered Electron In-lens Detectors

WINSON C. H. KUO, MARTHA BRICENO and DOGAN OZKAYA — Tue, 01 Apr 2014 00:00:00 GMT

Editorial

SARA COLES — Wed, 01 Jan 2014 00:00:00 GMT

Focused Ion Beam and Nanomechanical Tests for High Resolution Surface Characterisation: New Resources for Platinum Group Metals Testing

By Marco Sebastiani, Marco Renzelli, Paolo Battaini and Edoardo Bemporad — Wed, 01 Jan 2014 00:00:00 GMT

Recently, the increasing importance and scope of nanotechnology has extended the need for high resolution characterisation tools beyond their traditional domains. As a consequence, advanced high-resolution tools at the nanoscale are now increasingly used in research and development (R&D) activities, offering the chance for a better understanding of submicron feature size dependence. This paper gives an overview of the synergic application of two high resolution techniques on the platinum group metals (pgms): focused ion beam (FIB) coupled with electron beam imaging, milling and deposition techniques; and nanoindentation testing. After a brief description of both techniques (architecture, probe-sample interaction basics and operation modes), the effectiveness of this combined approach is demonstrated for microstructural and nanomechanical investigations on very small samples. The advantages are low cost, fast and site-specific sample preparation for transition electron microscopy (TEM) analysis; study of the mechanical hardening effect on microstructure and hardness profile at the micron scale; failure analysis; and understanding of plasticity and elasticity behaviour. Two specific case studies related to a platinum-copper alloy for jewellery use and a platinum-rhodium alloy for sensor manufacturing are presented and discussed.

High Temperature Thermomechanical Properties of Titanium-Rhodium-based Alloys Containing Scandium

By Yurii V. Kudriavtsev and Elena L. Semenova — Wed, 01 Jan 2014 00:00:00 GMT

At high temperatures, the equiatomic binary compounds formed by Groups 4 and 8 transition metals are known to undergo martensitic transformation, which may be accompanied by a shape memory effect. Among these compounds, titanium-rhodium (TiRh) is of special interest not only because it undergoes two martensitic transformations at high temperature, for one of which the shape memory effect has been observed, but also because it demonstrates unusual shape recovery behaviour at temperatures higher than 400°C. The present work focuses upon the thermomechanical and mechanical properties of 50 at% rhodium-scandium-titanium ternary alloys where Ti is substituted by Sc. These alloys were investigated for the first time using electrical resistance, dilatometry and three-point bending techniques in the temperature range 20°C to 850°C. It was found that the sample with 0.1 at% Sc exhibited full shape restoration in the ranges of both martensitic transformations at ~340°C and ~750°C. Two-way shape recovery was also observed. A small temperature hysteresis, desirableforalloysused inactuator applications, is present in TiRh and Rh-Sc-Ti alloys. Both TiRh and Sc-containing alloys exhibit continuity of the deformation process on cooling and shape restoration on heating in a wide range of temperatures. This feature of both TiRh and Rh-Sc-Ti alloys implies the possibility of their application in different heat-regulating elements at temperature ranges from room temperature to 850°C.

EuropaCat XI

Wed, 01 Jan 2014 00:00:00 GMT

The Discoverers of the Isotopes of the Platinum Group of Elements: Update 2014

JOHN W. ARBLASTER — Wed, 01 Jan 2014 00:00:00 GMT

PGMs IN THE LAB: Platinum Group Metals in Polyoxometalates

Wed, 01 Jan 2014 00:00:00 GMT

Publications in Brief

Wed, 01 Jan 2014 00:00:00 GMT

Abstracts

Wed, 01 Jan 2014 00:00:00 GMT

Patents

Wed, 01 Jan 2014 00:00:00 GMT

Final Analysis: Effects of Platinum Group Metals Doping on Stainless Steels

ANDREW FONES and GARETH D. HATTON — Wed, 01 Jan 2014 00:00:00 GMT

The Directed ortho Metallation–Cross-Coupling Fusion: Development and Application in Synthesis

Tue, 01 Oct 2013 00:00:00 GMT

This review constitutes a detailed but non-exhaustive examination of the directed ortho metallation (DoM)–cross-coupling fusion in its many flavours. Special attention is paid to the application of the concept of the linked reactions and the synthetic utility that it endows, particularly in the case of one-pot reactions that can greatly increase the ease and efficiency of the process. Personal experience of particular issues that can arise from these reactions and examples of their solutions are given, as well as illustrations of the rapid access to complex molecules that the technique encourages.

The Role of Platinum in Proton Exchange Membrane Fuel Cells

Oliver T. Holton and Joseph W. Stevenson — Tue, 01 Oct 2013 00:00:00 GMT

Proton exchange membrane fuel cells (PEMFCs) dominate the transportation fuel cell market and platinum (Pt) is the catalyst material used for both anode and cathode. This review sets out the fundamentals of activity, selectivity, stability and poisoning resistance which make Pt or its alloys the best available materials to use in this application. It is clear that Pt is the only element which can meet the requirements for performance while avoiding slow reaction kinetics, proton exchange membrane (PEM) system degradation due to hydrogen peroxide (H2O2) formation and catalyst degradation due to metal leaching. Some of the means by which the performance of Pt can be enhanced are also discussed.

“Organometallics as Catalysts in the Fine Chemical Industry”

Michel Picquet — Tue, 01 Oct 2013 00:00:00 GMT

A Study of Platinum Group Metals in Three-Way Autocatalysts

Jonathan Cooper and Joel Beecham — Tue, 01 Oct 2013 00:00:00 GMT

The price differential between platinum and palladium has driven the industry to adopt emissions control catalyst formulations for gasoline engines that contain higher levels of Pd than Pt, and in most cases no Pt. In addition fluctuations in the price of rhodium have led to thrifting of this metal. This study compares the performance of ten different catalyst compositions with varying ratios of Pt, Pd and Rh for a Euro 5 vehicle and under bench test conditions. The results show that a system with low Rh loading can readily be improved by increasing the Rh loading and there is a relatively large effect of doing this by a small amount. Increasing the Pd or Pt loading also improves emissions performance but by a significantly smaller amount than the effect of changing the Rh loading. Conversely it may be possible to decrease the Pt or Pd loading with only a small effect on emissions. Furthermore it was found that Pd outperforms Pt under most conditions, although not significantly. The difference appears greater under more stressful conditions such as high-speed driving or wide perturbation amplitude.

Recovery of Palladium from Spent Activated Carbon-Supported Palladium Catalysts

Şerife Sarioğlan — Tue, 01 Oct 2013 00:00:00 GMT

Activated carbon-supported palladium catalysts are liable to progressive deactivation even in the absence of any gaseous contaminants during the oxidation of hydrogen under ambient conditions. The high value of palladium coupled with environmental considerations means that new, efficient and cost effective methods for the quantitative recovery of palladium from such materials are required. In the present study, a process for extracting precious metals from spent catalyst or inorganic waste was developed. Palladium was extracted from the spent catalyst with an acid solution containing dilute hydrochloric acid and hydrogen peroxide at leaching temperatures of around 90°C. Palladium in the leached solution was then precipitated by use of sodium borohydride solution. The effectiveness of the method for recovery of precipitated palladium was investigated by ultraviolet-visible (UV-vis) spectrophotometry, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The recovered metallic palladium was of a suf cient grade to manufacture fresh activated carbon-supported palladium catalysts.

“Catalysts for Alcohol-Fuelled Direct Oxidation Fuel Cells”

Alex Martinez Bonastre — Tue, 01 Oct 2013 00:00:00 GMT