In this study, catalytic activity of carbon dioxide reforming of methane was investigated over nickel-cobalt catalysts in various structural forms. Catalytic activity tests were performed at the temperatures of 600-800 degrees C in a micro-flow quartz reactor. SEM-EDX, XRD and XPS studies were also performed to understand the surface morphology of the catalysts. The results showed that 8 wt%Ni-2wt.%Co on wash-coated MgO over monolithic structure led to highest catalytic performances with CH4 and CO2 conversions of 83% and 89% respectively as well as H-2/CO ratio of 0.95 at 750 degrees C. SEM-EDX and XPS results of catalyst spent at 750 degrees C also showed considerable amount of coke formation; however, the use of 3% oxygen in the feed suppressed the coke formation significantly. The catalyst was stable for 48 h in the presence of O-2 (3%) added feed at the temperature of 750 degrees C. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.