The distributions of measured acetylene conversions (X C2H2 ) and ethylene selectivities (S C2H4 ) are shown in black in Fig. and, respectively. These distributions correspond to measurements of the 12 materials under three T oven and associated to a number of t OS values between 0 and 405 min. In total, 1,076 measurements were performed. The distribution of measured X C2H2 values is highly concentrated around the values of 0.0 and 1.0, indicating that most of the materials and reaction conditions either result in inactive systems or in full conversion of acetylene, respectively. The high exothermicity of the reaction at such harsh reaction conditions impedes active catalysts to stabilize at acetylene conversion levels below 100 % without sophisticated cooling systems. We refer at this point to the work from Van Heerden on stationary states in autothermic processes. For this reason, we decided to analyze catalyst performance for all catalysts at stable full conversion levels even though this situation is not ideal in consecutive hydrogenation reactions such as the acetylene hydrogenation reaction. The distribution of measured S C2H4 values is in the approximate range [-1.0, 0.75], reflecting that the tested materials and conditions result in diverse behaviors ranging from totally unselective to highly selective hydrogenation of acetylene. A significant number of measurements results in S C2H4 close to -1.0, which correspond to total hydrogenation of both acetylene and co-fed ethylene to ethane. Additionally, many systems are associated to S C2H4 = 0, which indicates either equivalent rates of cofed ethylene hydrogenation and ethylene formation from acetylene or no activity (X C2H2 = 0).