A method for preparing a non-thermal plasma reactor substrate includes disposing electrical vias on green stage first and second ceramic plates; filling the electrical vias with conductive material; and forming electrical contact via cover pads; disposing conductive material on the first ceramic plate to form an electrode plate having a main electrode portion and a terminal lead for electrically connecting the main electrode portion to the electrical vias; laminating the electrode plate and the second ceramic plate together, embedding the electrode therebetween; co-firing the plates to form a laminated co-fired embedded-conductor element; stacking a plurality of the laminated co-fired embedded-conductor elements to form a multi-cell stack, the filled electrical vias aligning in the stack to provide an electrical bus for connecting alternating elements in the stack; and disposing spacers with matching vias and via cover pads between adjacent pairs of elements to form exhaust gas passages.