Comparison of Figs. 1 and 2 (tables S1-S3 and S5-S7), shows that Ge addition to Ptn had several effects. Ca. 30% less C2D4 desorbed from the Ge/alumina surface than from alumina, indicating that Ge blocked some sites for 150 K C2D4 adsorption on alumina, presumably because both Ge and C2D4 adsorption tended to occur at similar alumina defect sites. Intact C2D4 desorption occurred in distinct low and high temperature features for both Ptn/alumina and PtnGem/alumina but run-to-run stability was far higher for the Ge-treated samples. D2 desorption (i.e., carbon deposition) was largely, but not entirely suppressed in the Ge-treated samples and occurred with distinctly bimodal temperature dependence.