PARIS, Oct 1 (Reuters) - French companies TotalEnergies , Air Liquide and Vinci announced the launch of what they said would be the world's largest clean hydrogen infrastructure fund, as companies increase their presence in the green energy sector.

The companies said this fund aimed to reach 1.5 billion euros ($1.74 billion), and had already secured initial commitments of 800 million euros.

"We believe that clean, renewable hydrogen will play a key role in the energy transition, and TotalEnergies wants to be a pioneer in its mass production," said TotalEnergies Chairman and CEO Patrick Pouyanne.

"We are currently working on several projects, notably to decarbonize the grey hydrogen used in our European refineries by 2030. We are convinced that a collective effort is needed to kick-start the hydrogen sector and take it to scale," he added.

($1 = 0.8637 euros) (Reporting by Benjamin Mallet; Editing by Sudip Kar-Gupta)