Reducing gaseous carbon dioxide to valuable chemicals and fuels by using gaseous hydrogen can decrease the concentration of greenhouse gases that contribute to global warming. Carbon dioxide conversion into fuels such as methane, methanol, and formic acid is a good hydrogen-storage method. In this paper, a comparative study of CO2 conversion into formic and acetic acids on alumina-supported nickel oxide with and without the presence of carbon is reported. NiO (111) with high surface area was synthesized through a simple and one-pot fusion solid-state method at 550 degrees C and 700 degrees C. The synthesized catalysts were tested in carbon dioxide hydrogenation reaction in a batch slurry reactor at 130 degrees C and under mild pressure. Interestingly, the optimum condition of the reaction also successfully produced C-2 carboxylic acid in significant amounts. The highest levels of formic acid and acetic acid production were 8.13 and 7.63 mmol/L, respectively. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.