Conversion of methane by an electric barrier-discharge plasma using an inner electrode with discharge disks set at 5 mm intervals

•The between discharge disks with 5mm interval can increase methane conversion.•The interval can improve the selectivity of propane, C4 and over hydrocarbon.•The product carbon selectivity is not changed with increasing flow rate at Pw of 32W.•The product carbon selectivity of both reactors is different at Pw of 3W.