At a speech at the Farnborough Airshow on Monday, she will offer more than £300m of government money for several projects.
In the first six months of this year, electric vehicles made up 5.5% of the UK’s new car market, compared with 4.3% over the same period in 2017.
The 25% levy came into effect at midnight Washington time.
Purplebricks’ share price fell 4.7% to 303.65p in early trading.
Shares in Sainsbury’s rose by 0.44% to 318.6p in early trading.
The subpoena from the US Department of Justice is in relation to compliance with the Foreign Corrupt Practices Act and money-laundering laws.
CO2 is used to kill farm animals before processing and in packaging to keep meat fresh but is in short supply.