As-prepared Pt4Ge/alumina also gave weak D2 TPD signal, peaking near ~200 K, implying that a single Ge atom also substantially decreased the D2 chemisorption probability and reduced the Pt-D binding strength. The onset of D2 desorption was well below the D2 desorption onset for C2D4 TPD from Pt4Ge, again suggesting that C2D4 decomposition is rate limiting. Subjecting Pt4Ge to two C2D4 TPD runs prior to the D2 TPD run resulted in only a small additional reduction in the D2 desorption signal, with no significant effect on the temperature dependence.