The major R&D groups within Air Liquide focus on analysis, bioresources (foods and chemicals), combustion, membranes, modeling, and the production of hydrogen (H2) gas.

On May 25, 1902, and after two years of research, Georges Claude developed a process for liquefying air in order to separate the components (oxygen, nitrogen, argon).

On November 8, 1902, Paul Delorme gathered twenty-four subscribers, mainly engineers, to financially support the project,[5] and became the first president of "Air liquide, a company for the study and exploitation of Georges Claude processes".

[citation needed] In 1906, Air Liquide began operations in Belgium and Italy, followed by Canada, Japan and Hong Kong.

[8] In 1986, Air Liquide expanded into the United States with the acquisition of Big Three for $1.05 billion, a US-based company with operations in many countries across Europe and Asia.

[13] In 2001, Air Liquide acquired Messer Griesheim's operations in South Africa, Trinidad and Tobago, Canada, Egypt, Argentina and Brazil for €185 million.

[14] That same year, Air Liquide acquired the remaining 57% it did not yet hold from Hede Nielsen, a Danish company, which it had partially bought back in the 1990s.

[16] In 2005, Air Liquide acquired the remaining 13.2% in the Far East Oxygen and Acetylene Company (SOAEO), for an approximately amount of €150 million.

[20] In early 2008, Air Liquide entered a long-term contract with Neste Oil's Renewable Diesel Plant to supply hydrogen.

[21] In 2012, Air Liquide created a joint venture with the Belgian group Solvay, to produce fluorinated gases for flat screens and photovoltaic panels.

In 2013, Air Liquide created ALIAD, a venture capital investor, with the objective to invest in start-ups and future technologies specializing in the energy transition, health and digital sectors.

[27] In November 2015, Air Liquide announced it would acquire the American firm Airgas for a total of $13.4 billion, including debt.

[33] ALIAD's investments focus on health, energy transition and high-tech start-up, and support them by setting up privileged R&D and business agreements.

[39] In January 2018, the group announced an investments of 150 million euros in Asia to finance the construction of ultra pure nitrogen production units, a "carrier gas" used in the composition of various electronic applications.

In February 2018, Air Liquide launched the world's largest oxygen production unit for Sasol, an international energy and chemicals company.

The campus includes Air Liquide's largest Research & Development Center, fully renovated with an investment of €50 million.

[citation needed] According to the International Energy Agency, Air Liquide is actively partnering in carbon capture, utilization and storage (CCUS) projects across Europe and the United States.

[1] Air Liquide generates about a third of its sales revenue by supplying the large industry (26% in 2017): chemicals, petrochemicals, metallurgy and refining.

[43] In February 2018, Air Liquide launched the world's largest oxygen production unit for Sasol, an international energy and chemicals company based in South Africa.

[46] The main medical gases manufactured are: The Group also provides hygiene and disinfection solutions, through its German subsidiary Schulke [de] (Germany), as well as sterilization of surgical instruments, to fight against nosocomial diseases.

For its activities in research and development in the health sector, Air Liquide formed partnerships with several international research centers such as MGH (Massachusetts General Hospital, Boston, USA), ICM (Institut du Cerveau et de la Moelle épinière, France), Pasteur Institute, (France) or Leuven University (Belgium).

[citation needed] In 2020, Air Liquide along with Schneider Electric, Groupe PSA, and Valeo were asked to produce ventilators for intensive care units (COVID-19) by the Health Department.

During the Artemis 1 wet dress rehearsal the level of flow was insufficient, something that will be solved by a planned upgrade of separation equipment.

[56] For space missions, Air Liquide creates cryogenic equipment for launchers, orbital systems, firing points and sensors cooled at very low temperatures.

Its new units doubled Air Liquide's biomethane capacity, reaching 60MW, the equivalent of 500 GWh for a full year of production.