 BOSTON--BUSINESS WIRE--Advent Technologies Holdings, Inc. NASDAQ: ADN Advent today joins the U.S. in celebrating the 7th Annual National Hydrogen and Fuel Cell Day, which marks the growth of the industry by raising awareness of the benefits fuel cell technologies and hydrogen energy provide in reducing emissions while driving economic growth. National Hydrogen and Fuel Cell Day is observed on October 8 in recognition of the atomic weight of hydrogen - 1.008. Hydrogen is already providin 