BOSTON–(BUSINESS WIRE)–Advent Technologies Holdings, Inc. (NASDAQ: ADN) (“Advent”) today announced that Dr. Vasilis Gregoriou, Advent Chairman and CEO, welcomed the U.S. Ambassador to Greece, Geoffrey R. Pyatt, to the Company’s facilities at Patras Science Park. During the Ambassador’s visit there was a walking tour of the production areas of Advent Technologies SA at Patras Science Park. The productions areas are: FC Stacks/Hardware R&D and Manufacturing Area This area is a dedicated are