The anode reactions of solid oxide electrolyte based carbon fuel cells (SO-CFCs) are explored by comparing the electrochemical behaviors of SO-CFCs under varying anode carrier gas flow rates (FAr) and at different contact modes. The electrochemical performance of four raw carbon fuels, including a graphitic carbon (GC), two coals (lignite CF and anthracite YQ) and an activated carbon (AC), and their chars is tested to investigate the influence of carbon fuel properties on the cell performance. The results show that CO electro-oxidation and C-CO2 gasification were main anode reactions. The direct carbon electro-oxidation is insignificant under high FAr. Polarization performance of the chars under high FAr was similar with that of 5-10% CO. It is also concluded that the cell performance is greatly dependent on the carbon fuel gasification reactivity with CO2. Thermal pretreated AC displays the best durability performance for its stable and moderate CO2 gasification rate. Additionally, the coal ash does not affect the cell performance significantly. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.