Exhibit 23.1

INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM’S CONSENT

We consent to the inclusion in this Registration Statement of Advent Technologies Holdings Inc. (formerly known as AMCI Acquisition Corp.) on Form S-1 of our report dated March 27, 2020, which includes an explanatory paragraph as to the Company’s ability to continue as a going concern, with respect to our audits of the financial statements of AMCI Acquisition Corp. as of December 31, 2019 and 2018 and for the year ended December 31, 2019 and for the period from June 18, 2018 (inception) through December 31, 2018, which report appears in the Prospectus, which is part of this Registration Statement. We were dismissed as auditors on February 4, 2021 and accordingly, we have not performed any audit or review procedures with respect to any financial statements appearing in such Prospectus for the period after the date of our dismissal. We also consent to the reference to our Firm under the heading “Experts” in such Prospectus.

/s/ Marcum LLP

Marcum LLP

New York, NY

February 16, 2021