Carbon dioxide and methane reforming using a unique DC arc plasma reactor without catalyst could achieve high conversions and selectivity in milliseconds. Very little coke was formed during the course of reaction. Influences of the total flow rate and molar ratio of CO2 to CH4 at an input power of 170W were studied to find the optimum operating conditions. Increasing the input energy density promoted the conversions of reactants and reduced the formation of the by-products efficiently. The conversions of CO2 and CH4 reached 89.8% and 96.3%

respectively

and the selectivities to H2 and CO products were 99.6% and 99.3%

respectively

where the mole ratio of CO2 to CH4 was 1. Excessive CO2 could benefit the conversion of CH4 and result in the high selectivity to syngas. Specific energy requirement (SER) was used to express the energy utilization efficiency of the process

providing a practical guidance on optimization of reaction conditions to increase the energy efficiency.