Activity trends for 22 metals and metal alloys are reported for the conversion of CO2 and CH4 to 2 : 1 H2 : CO syngas and carbon. A correlation is observed between CO2 conversion and the free energy of oxidation by CO2 on pure metal catalysts. Indium and indium alloys activate CO2 at the highest rates. We identify a new bifunctional 20 : 80 mol% Sn-In alloy that activates both CO2 and CH4 while catalyzing both reactions.