It is with much regret that we report the death of Sir John Meurig Thomas.

Sir John was renowned for his work in the science of catalysts and solid state chemistry. The production chain of many modern materials and chemicals involves catalysts — substances that speed up chemical reactions, but use less energy and do not get used up themselves. John led the way in developing ‘green’ catalysts to make chemical processes less polluting and more efficient.

Sir John pioneered the use of technologies like electron microscopy and neutron diffraction to ‘see’ how minuscule surface features of catalysts affect chemical reactions. He had particular expertise in heterogeneous catalysts — ones that are in a different phase to the reacting chemicals, such as a solid material that catalyses reactions of liquids.

Sir John, a Founding Fellow of the Learned Society of Wales, was awarded the Royal Society’s 2016 Royal Medal in Physical Sciences for his pioneering work within catalytic chemistry, in particular on single-site heterogeneous catalysts, which have had a major impact on green chemistry, clean technology and sustainability.

Sir John began his academic life at the University of Wales, Swansea, and he is the first graduate of the University to receive a Royal Medal. Sir John had further connections to many Welsh Universities, including working for the University of Wales Bangor, being a former Head of Chemistry at the University College of Wales, Aberystwyth, being a former Deputy Pro-Chancellor of the University of Wales and an Honorary Distinguished Professorship of Materials Chemistry at Cardiff University.

Sir John was director of the Royal Institution from 1986-1991 and had been Head of the Department of Physical Chemistry at the University of Cambridge, and later Master of Peterhouse College. Sir John was knighted in 1991 for his services to chemistry and the popularisation of science.