Sir John Meurig Thomas, chemist and populariser of science known for work on catalysts – obituary

Sir John Meurig Thomas, who has died aged 87, was one of the most influential British chemists of recent times, a founder of what is called solid-state chemistry who was best known for his work on catalysts, such as zeolites and clays, which speed chemical reactions inside their pores, chambers and cavities. The mineral meurigite is named in his honour.

Thomas would become Director of the Royal Institution, and when he marked his 75th birthday, the celebrations were attended by Nobel laureates and the world’s best-known quantum chemist, Angela Merkel, whom he had got to know after working with her husband, the computational chemist Joachim Sauer.

With his rich voice and brilliant turn of phrase, Sir John was a prolific author, superb orator (in both English and Welsh) and influential populariser of science. In 2014 he became the President of the National Eisteddfod of Wales, where in his address he declared: “I am proud, indeed I rejoice in the fact of my being a Welshman” , and paid tribute to the influence of Wales’s Christian culture, saying: “It was in the chapel that I learned to be an academic by listening to and analysing very many powerful sermons.”

He remained active throughout his life. In 2020 he published Architects of Structural Biology, which describes the key figures in the 20th-century fusion of chemistry and physics in molecular biology, and in October took part in an online event at the Science Museum with his former Cambridge colleague, Dame Mary Archer.

John Meurig Thomas was born on December 15 1932 and brought up in the Gwendraeth Valley, Carmarthenshire, Wales. His options at that time in that place were limited, he recalled: “To become a preacher, teacher, or work underground.”

Both his father and his brother, 12 years his senior, were miners. Thomas later reflected that if their births had been reversed, “I would have ended up a coal miner and he a professor. He was a very intelligent man, as was my father.”

Instead of following them down the pit, Thomas was inspired as a teenager by Irene James, his physics teacher at Gwendraeth Grammar School, where “the flame of science was lit in my heart and in my mind”.

He wrote of her: “She was astonishingly good, talking about the great scientists such as Newton and Rutherford and at length about Michael Faraday. I was enthralled when I heard her describe how this man who had left school at the age of 13 with little knowledge, other than arithmetic, became a bookbinder’s assistant and then ended up being one of the greatest scientists of all time. I was in awe of Faraday from that moment onward.”

Thomas gained his BSc in 1954 and doctorate a few years later from the University of Wales, Swansea. A glimpse of his future contribution to chemistry came when he spent a year working at the United Kingdom Atomic Energy Authority as scientific officer, where he “rubbed shoulders with metallurgists”.

They spoke a language he did not understand when it came to defects, dislocations and imperfections. He began by looking at how dislocations influenced the stability of the graphite used in gas-cooled nuclear reactors; it was research that would inspire him to take an interest in how minuscule surface features – such as dislocations – influence the chemical, electronic and catalytic properties of solids.

He joined the department of chemistry at the University of Wales, Bangor, where he rose through the ranks from assistant lecturer to reader, enjoyed what he referred to as “total intellectual freedom”, and did research to reveal the profound influence that structural imperfections have on chemical properties: the surface of a catalyst is not all active, only defects such as corners and edges.

While there he pioneered the use of electron microscopy – what he described as his “single best” decision in his scientific research. Today, every chemistry department uses the technique.

In 1969 he became Professor and head of Chemistry at the University College of Wales, Aberystwyth, where he broadened his interests to create one of the finest departments of solid-state chemistry in Europe and where his work on defects attracted the attention of Cambridge.It also caught the attention of the Royal Society. In 1977 he was elected a Fellow, and the following year he joined the University of Cambridge as head of the department of Physical Chemistry, extending his solid-state studies with new techniques to study materials such as neutron scattering and nuclear magnetic resonance.

In 1986 BP used one of his patented acid catalysts to make hundreds of thousands of tons of ethyl acetate within the biggest plant of its kind in the world.

The same year, Thomas was invited to succeed Sir George Porter as Director of the Royal Institution and Fullerian Professor of Chemistry, the position held by his scientific hero, Michael Faraday.

He now lived in the same quarters that Faraday once occupied in the Royal Institution’s building on Albemarle Street, London, sat in Faraday’s chair and worked at his desk. “When I retired at night, the bathroom furniture had a brass plate bearing his signature; and each time I gazed at it, I felt, knowing how prodigiously hard he used to work, that I had not done enough to earn a night’s sleep.”

During his inaugural lecture in 1986, sitting before Thomas in the front row of the lecture theatre was Irene James, the teacher who had first fired up his interest in Faraday. “It was a great moment,” he recalled.

At this time, Thomas began using synchrotron radiation (synchrotrons are powerful sources of X-rays) and devised techniques which combine X-ray spectroscopy and high-resolution X-ray diffraction to study the atomic structure of the active sites of solid catalysts as they worked.

He devised new “single site” heterogeneous catalysts, which are in a different phase, such as a solid material that catalyses a chemical reaction in liquids. These include mesoporous, microporous, and nanoporous catalysts, which offer active sites at different length scales, the latter being the size of molecules.

In 1987, the BBC televised Thomas’s Royal Institution Christmas Lectures on crystals, with David Phillips, continuing the tradition of lectures for children started in 1825 by Faraday.

His former postdoctoral student, Dewi Lewis, said that Thomas’s work at the RI defined his greatest contribution to chemistry, and recalled his prodigious knowledge and propensity to speak Welsh, along with a Friday ritual when he would march his research group to the Royal Society for lunch “at a ferocious pace, talking science all the way and diving between taxis.”

Another former RI colleague recalled that Thomas’s time at the Institution was marred by its fragile finances, unfathomable spats with colleagues, and how, each October, he would “sit by the phone, waiting for the call from Stockholm – we called it Nobel purdah.”

Little wonder, though, as Thomas had written more than 1,100 research papers with an impact factor – what scientists call an H-index – of 95, more than many Nobel laureates.

He was the author of around 30 patents, held numerous honorary doctorates and honorary positions in several universities, honorary membership of more than 15 foreign academies, and garnered many awards.

In 1991 Thomas published Michael Faraday and the Royal Institution: The Genius of Man and Place. However that year he resigned as Director owing to the poor health of his wife, Margaret; they had married in 1959 and had two daughters, Lisa and Naomi.

Thomas would remain associated with the Davy Faraday Research Laboratory of the Royal Institution until 2006.

After a time as Deputy Pro-Chancellor of the University of Wales (1991–1994), Thomas returned to Cambridge in 1993 as Master of Peterhouse, where he revelled in being the first Left-winger to run the university’s oldest college, having once hosted at the RI the launch of the Labour party’s science policy with the then Leader of the Opposition, Neil Kinnock.

Thomas was knighted in 1991.

A colleague joked that Thomas was “endearingly egotistical”, noting that his entry in Who’s Who was one of the longest in the book, at least after Barbara Cartland’s.

Sir John Meurig Thomas remained at Peterhouse until 2002, when his wife died. In April 2010 he married Jehane Ragai, an emeritus professor of chemistry at the American University in Cairo.

Sir John Meurig Thomas, born December 15 1932, died November 13 2020