Johnson Matthey Technology Review - Current Issue

Platinum group metals (PGMs) are key for various applications in electronics, optics, medicine, sensing, catalysis, energy conversion, water or air treatment and many more. Unfortunately, platinum, palladium, ruthenium, rhodium, iridium and osmium are limited resources. If efficient recycling is a key aspect of the life cycle of PGMs, another important aspect is the optimal actual use of the PGM resources. Optimal use can be achieved by designing nanomaterials down to the atomic scale to make the most of every single PGM atom. In this direction, a parameter often overlooked is the careful selection and development of the synthetic routes selected to obtain the desired PGM-based nanomaterials. Indeed, the way the nanomaterials are obtained can greatly influence their resulting properties and condition their use, activity, stability and potentially even their recyclability. For PGMs to truly contribute to more sustainable technologies and processes, how PGM nanomaterials are obtained could benefit from more sustainable syntheses. An account of emerging simpler and potentially more sustainable syntheses of PGM nanomaterials, their various benefits and remaining challenges is proposed.

Driven by the needs of a developing business unit, in 1994 ICI Katalco (which later became part of Johnson Matthey) started a collaboration with the University of Birmingham’s School of Chemical Engineering on the scale up of a novel multiphase reactor technology: single technology and interest, single academic. This has morphed over the last 30 years into a broader collaboration across the School involving some 17 members of academic staff across an ever-broadening technical scope. While not unique in terms of longevity of a Johnson Matthey academic collaboration, others have been a relationship with a single academic. To date the collaboration with Birmingham has included over 30 graduate students, resulted in approximately 70 co-authored publications in refereed journals and leveraged approximately £7 million (2024 terms) of research funding for the University. This paper will review in general and specific terms, using case histories, how this relationship has been managed to the mutual benefit of both partners as a blueprint for long term, broad industrial-academic collaboration.

This is Part II of an investigation of the most recent developments in reactors for the ODS process. Here we present a discussion of the types of catalyst used in the ODS process along with the kinetics, mechanisms and reactor types. The advantages of OBR over conventional reactors are described.

The present work is devoted to revealing kinetic regularities of carbon monoxide oxidation using palladium on carbon (palladium black) and alumina with the addition of 0.1 mass% and 0.04 mass% of palladium as catalysts. The initial pressures of carbon monoxide and oxygen were: PCO = 0.13–1.33 kPa and PO2 = 2.67–16 kPa. The reaction was studied in the temperature range of 70–210°C. Small addition of palladium (0.04–0.1 mass%) to alumina led to a significant increase in catalytic activity.

Palladium(II) oxide/γ-alumina (PdO/γ-Al2O3) catalysts are one of the most active catalytic components for the complete oxidation of methane. Under reaction conditions, especially in a wet feed, the catalysts suffer severe performance degradation. This study establishes a series of testing protocols to systematically investigate the causes of catalyst deactivation under methane oxidation reaction conditions. Four distinct catalyst deactivation modes are identified. Two of the deactivation modes are directly related to water, either from the feed gas or as a part of the reaction products, with one (Mode 2) being attributed to the formation of surface hydroxyl groups and the other (Mode 3) to the competitive adsorption of water on the catalysts. The impact of the two deactivation modes is acute and severe but reversible. In contrast, the other two deactivation modes are gradual and persistent but irreversible. Both modes are induced by methane oxidation reaction, with the impact of a wet feed (Mode 4) being substantially more severe than that of a dry feed (Mode 1). The major cause of the irreversible catalyst deactivation is attributed to surface reconstruction of palladium(II) oxide nanoparticles, which behaves as a passivation layer lowering the number of coordinately unsaturated palladium sites for methane activation. Although the passivation layer is relatively stable against thermal or hydrothermal treatment, it is not completely inert. Formation and partial regeneration of the passivation layer is a highly dynamic process and heavily depends on the reaction temperature: a lower reaction temperature (≤450°C) can lead to quicker catalyst deactivation; but a higher reaction temperature (between 500–550°C) can result in a greater extent of catalyst deactivation.

The intermetallic compounds X-aluminium (X = ruthenium, iridium, nickel) show unique combinations of mechanical strength, thermal stability and oxidation resistance, making them attractive for advanced structural and functional applications. The present work explores the ultrasonic properties of selected materials for understanding their thermophysical temperature-dependent behaviour. The thermophysical properties for selected intermetallic compounds X-aluminium such as specific heat, energy density, thermal conductivity, Debye temperature and thermal relaxation time have been enumerated using second and third order elastic constants (SOECs and TOECs) via the Born potential model in the temperature range 0–500 K. The ELATE visualisation tool has been used to envision mechanical parameters such as Young’s modulus, shear modulus, Poisson’s ratio and compressibility (linear) at zero pressure for ruthenium-aluminium, iridium-aluminium and nickel-aluminium in three dimensions (3D). The mechanical and ultrasonic properties of X-aluminium such as shear modulus, Young’s modulus, Zener anisotropic factor, Poisson’s ration, Pugh’s ratio and ultrasonic wave velocities for longitudinal and shear modes along <100>, <110> and <111> directions have been enumerated using the established mathematical model. Finally, all computed parameters have been utilised to evaluate the ultrasonic attenuation for the selected intermetallics. The obtained results are discussed and cumulated with available results on the materials for further analysis of intermetallic bonding, phase stability and high-temperature behaviour.