File Name : figure s1.tif Caption : figure s1. h-cell details and plasma reactor dimensions. File Name : figure s2.tif Caption : figure s2. the i-t curve for a single electrocatalytic reaction process. File Name : figure s3.tif Caption : figure s3. the ac-powered gliding arc discharge exhibited two distinct discharge modes (a) a-g mode, and (b) b-g mode. File Name : figure s41.tif Caption : figure s4. optical emission spectrum of the air rotating gliding arc.