Chenevix went to Paris after his university studies. He was imprisoned there for 15 months during the Reign of Terror. While in custody he had two children; also, amongst his fellow prisoners were a number of chemists who whetted his interest in the topic. After his release he studied at three different schools in Paris, gaining skills in chemical analysis. In 1798 he wrote his first paper, in French: Analysis of some magnesium rocks in Annales de Chimie. Thereafter, in journals both sides of the Channel, he reported analyses of hydrochloric and sulphuric acids, compounds of lead, copper, iron, arsenic, carbon and sulphur and crystals of corundum including sapphires and rubies. He was made a fellow of the Royal Society in 1801 as a result of this work.
He wrote a paper in England in 1802 supporting French Neologist-inspired changes to chemical nomenclature. During a year in Germany, he published criticisms of the work of ground-breaking scientists: Danish chemist and physicist Hans Christian Ørsted and the German physicist, chemist and mineralogist Christian Samuel Weiss. In 1803, in the Philosophical Transactions of the Royal Society, he published a paper asserting that the palladium that the English chemist William Hyde Wollaston had extracted from platinum ore the previous year (and had announced and offered for sale anonymously) was in fact an alloy of mercury and platinum. For this seemingly astonishing result, he was awarded the Copley Medal. Wollaston, again anonymously, offered a reward to anyone who could confirm Chenevixs claims experimentally. On his part, Chenevix published a second paper supporting his result in 1805, by which time hed made Paris his permanent home. Henry Cavendish, an admirer of Wollaston, was the sole Society objector in the vote for the publication. Later that year, Wollaston publicly revealed his authorship (although he had communicated as much to the Royal Society before Chenevixs second paper) and details of how he had, correctly, isolated the element palladium. Chenevix bore no apparent animus in later meetings between the two. How damaging the affair was to Chenevixs reputation as a chemist in the scientific world has been a discussion point for different writers. In 1808 came his criticism of Abraham Werners classification of minerals. In 1809, he produced his final scientific paper, a method to produce acetone by distilling acetates. An English translation of a paper he wrote in 1808 for Annales de Chimie was published in London in 1811 as Observations on Mineralogical Systems'.
Chenevix was a member of a number of European societies. The Royal Society has (a minimum of) twenty-six papers by Chenevix.