Moureu was widely respected for his research work. As part of his research on acrylic acid and its derivatives, he was the first to synthesize acrylonitrile in 1893.
In addition, he studied acetylene compounds, phenolic compounds, plant essences, and rare gases found in wells and mines.
During the war, Moureu researched acrolein and sulfur mustard gas, working with his student Charles Dufraisse.  
Acrolein was an extremely unstable compound, which tended to polymerize on contact with air.  Already familiar with the preparation of acrolein, Moureu and Dufraisse were able to develop a way to stabilize it after carefully studying the processes by which it altered. Their work led to the use of acrolein and later benzyl iodide in weapons.
Their research also had great impact and long-lasting significance after the war.   It was first published in the Bulletin of the Chemical Society of France in 1922.
The autoxidation reactions that Moureu and Dufraisse described occur spontaneously in most organic products in the presence of oxygen from the air and certain catalysts.  Autoxidation affects virtually all living organisms. Moureu identified catalysts that could trigger such reactions, and other compounds that could slow or inhibit such reactions. He  called the inhibitors "antioxygens", now known as "antioxidants". 
Moureu is best known for this pioneering research. It has led to the use of antioxidants in the rubber and vegetable oil industries,
and to widespread applications in foods and medicines. Antioxidants are added to slow the spoiling of foods and the aging of rubber.
Moureu's work with sulfur mustard also became important after the war, as later researchers realized that some of the chemicals that were in mustard gas could be used as anti-cancer drugs, suppressing the division and proliferation of blood and bone marrow cells in leukaemia and lymphatic tumours.
With Adolphe Lepape, Moureu studied rare gases including krypton and xenon.
He developed methods for analyzing the gaseous components of mineral springs, and carried out comparative analyses of at least 108 springs.