Platinum group metals (pgms) have never been more essential. They are already key contributors to technologies that have global impact: catalytic convertors (platinum, palladium, rhodium) that minimise air pollution; catalysts (platinum, rhodium) to produce nitric acid in fertiliser manufacture, which supports global food production; crucibles (iridium) for making scintillation crystals used in metal scanners and mobile phones; and hard disks (platinum, ruthenium) with enhanced storage capacity.

This special pgm edition of the Johnson Matthey Technology Review highlights how some of these long-standing applications are developing. For platinum jewellery, bulk metallic glasses are being investigated for their improved properties compared to cast alloys (1), while the mechanical properties of platinum-rhodium binary alloys and superalloys are being studied based on the impact of the valance electron ratio on metallic bonding (2). Platinum-rhodium alloys are crucial in the production of glass fibres, and here work is presented which investigates additive manufacture as a way to overcome limitations on fabricating equipment (3). The use of additive manufacture is discussed for making platinum-gold alloy jewellery using laser powder bed fusion technology (4).

Catalysis has always been a pivotal application of the platinum group metals, and this special edition features a discussion on progress in C–H activation by rhodium and iridium complexes, a potential future route to making chemical feedstocks from, ideally, sustainably derived hydrocarbons (5). Out of the H2020 Platinum Group Metals Recovery Using Secondary Raw Materials (PLATIRUS) project, novel technologies for improving the recovery of pgms from end-of-life catalysts are reported, including microwave assisted leaching and gas-diffusion electrocrystallisation (6).

Significant advances have been made in the potential environmental impact of pgm-catalysed processes by carrying out reactions in water instead of organic solvents and decreasing the use of energy and reagents. This is exemplified by a room temperature, aqueous electrochemical route for synthesis of monodisperse platinum-cobalt nanocrystalline catalysts (7) and ground-breaking work reported on aqueous micellar catalysis by palladium in water at ambient temperatures (8).

With particular reference to palladium in organic chemistry, the article by Professor Bruce Lipshutz (8) also raises concerns circulating in the academic community about whether there will be enough palladium to meet future demand in organic synthesis. In reality, Johnson Matthey’s pgm market insight indicates that palladium and rhodium will go from their current state of high demand and high price into a surplus position as road transport transitions away from the fossil fuel burning internal combustion engines towards zero tailpipe-emission vehicles (9). As a consequence, in upcoming decades there will be significant opportunities to use palladium and also rhodium in organic chemistry and in a range of new and growing applications.