In a grey building squeezed in an industrial corner of Brooklyn, New York, Stafford Sheehan shows me a jar full of black metallic pellets. “This is the special sauce,” he says. They don’t look like much, but he says they could help produce billions of litres of fossil-free liquid fuel.
Sheehan’s start-up, Air Company, is one of a growing set of manufacturers trying to use captured CO2 to replace products now made with fossil fuels, which can help to reduce emissions. But…
