 In that year he began teaching in the chemistry department of the University of Pennsylvania in Philadelphia, where he remained for twenty-two years, and where he became departmental chair and the Hirschmann-Makineni Professor, and founded the Penn Science Teacher Institute.In 2007 he became Dean of the College of Science and Technology of Temple University, also in Philadelphia, Pennsylvania, and was Provost of Temple University during 2013 - 2016.In 2017, Dai was appointed Vice President for International Affairs at Temple University.