[6][7] He was one of the founders of solid-state chemistry, starting with his work at the University of Wales, Bangor, in 1958 when he investigated the various ways in which dislocations influence the chemical, electronic and excitonic properties of a range of solids.

He was one of the first to exploit electron microscopy as a chemical tool, especially to deduce active-site reactivities from the surface topography of many minerals and crystal hydrates.

At the University of Aberystwyth (1969–1978) he elucidated the surface chemistry of diamond, clay minerals, metals and intercalates by pioneering UV and X-ray photoelectron spectroscopy.

As Fullerian Professor and Director of the Royal Institution and of the Davy–Faraday Research Laboratory, he utilized synchrotron radiation to characterize, in situ, new catalysts designed for green chemistry and clean technology.

[11][12] Thomas authored more than 1200 scientific articles and several books,[13][14] including Michael Faraday and the Royal Institution: The Genius of Man and Place (1991),[15] Principles and Practice of Heterogeneous Catalysis (with W. John Thomas, 1997, 2014),[16][17] and Design and Applications of Single-Site Heterogeneous Catalysts: Contributions to Green Chemistry, Clean Technology and Sustainability (2012).

[18][19] Thomas was born and brought up in the Gwendraeth Valley, Carmarthenshire, Wales,[7] near the mining town of Llanelli,[3] where his father and brother were miners.

For example, he extended his earlier electron microscopic and surface studies of minerals and intercalates to encompass the synthesis and structural determination of zeolitic materials by a combination of solid-state NMR, neutron scattering,[21] and real-space imaging.

[12][28] In 1991 Thomas published the book Michael Faraday and the Royal Institution: The Genius of Man and Place, which has since been translated into Japanese (1994) and Italian (2007).

[34] Thomas was the author of some thirty patents,[7] some of which have made chemical processes more environmentally benign ("greener") by eliminating the use of solvents and reducing the number of manufacturing steps involved.

[1] The single-step, solvent-free catalytic synthesis of ethyl acetate that he invented is the basis of a 200,000 ton/year plant in the UK, the largest of its kind in the world.

[44] Other awards included the Kapitza Gold Medal from the Russian Academy of Natural Sciences (2011),[22] the Jayne Prize Lectureship of the American Philosophical Society (2011), the Bragg Prize Lectureship of the British Crystallographic Association (2010), the Sven Berggren Prize Lectureship, Lund (2010), the Ertl Prize Lectureship of the Max Planck Gesellschaft (2010), the Sir George Stokes Medal from the Royal Society of Chemistry (2005),[23] the Giulio Natta Gold Medal from the Società Chimica Italiana (2004),[9]: x  the Linus Pauling Gold Medal from Stanford University (2003),[23] and the American Chemical Society Annual Award (first recipient) for Creative Research in Heterogeneous and Homogeneous Catalysis (1999).

[48][49] A hydrated potassium iron phosphate, meurigite is described as "tabular, elongated crystals forming spherical and hemispherical clusters and drusy coatings.

The papers presented were published in 2008 by the Royal Society of Chemistry as Turning Points in Solid-State, Materials and Surface Science: A Book in Celebration of the Life and Work of Sir John Meurig Thomas.

[9] In 2010 Imperial College Press published 4D Electron Microscopy: Imaging in Space and Time, which he co-authored with Ahmed Zewail (Nobel Laureate, Chemistry, 1999).

"[58] The JMT Medal will be awarded every year, to a person working in the United Kingdom, for outstanding achievement in catalysis or a closely related field.