Apparatus and methods for converting carbon dioxide and/or methane into higher alkanes and hydrogen gas in a single reaction chamber using a catalyst and microwave radiation. An apparatus for producing a product comprising at least one of the group of hydrocarbon having a formula CnHz where n is a positive integer greater than 1, and z is a positive integer between 2n + 2 and 2n hydrogen gas and. The apparatus comprises a reaction vessel for containing a reaction mixture of a gaseous carbon source represented by the letter W, selected from the group consisting of natural gas, CH 4 and CO 2 , and water (H 2 O), and having a catalyst and at least one microwave energy source.