Systems and methods are provided for selective oxidation of CO and/or C3− hydrocarbonaceous compounds in a reaction environment including hydrocarbons and/or hydrocarbonaceous components. The selective oxidation can be performed by exposing the CO and/or C3− hydrocarbonaceous compounds to a catalytic metal that is encapsulated in a small pore zeolite. The small pore zeolite containing the encapsulated metal can have a sufficiently small pore size to reduce or minimize the types of hydrocarbons or hydrocarbonaceous compounds that can interact with the encapsulated metal.