In the CO2 sequestration, a desirable yet challenging option is the photocatalytic conversion with solar irradiation. While nanoscale semiconductors have been at the center of attention in the development of suitable photocatalysts for the CO2 conversion, carbon nanoparticles have recently emerged as a new class of photoactive materials for harvesting visible photons to drive photocatalytic processes. Results from this study demonstrate that aqueous suspended bare carbon nanoparticles could be excited with visible light to photocatalytically convert CO2 into formic acid, with the performance competitive to that of widely used semiconductor nanoparticles. (C) 2015 Elsevier B.V. All rights reserved.