This paper reports the synthesis, characterizations and applications of well-crystalline 2D-cerium oxide (CeO2) nanoflakes prepared by a rapid and facile solution combustion process. The nanoflakes were characterized in detail and applied as photocatalyst for dye-degradation and as an efficient electron mediator to fabricate high-sensitive hydroquinone chemical sensor. The detailed characterizations revealed that the prepared nanoflakes were well-crystalline and grown in very high-density. The synthesized CeO2 nanoflakes exhibited good photocatalytic activity toward the photocatalytic degradation of direct red-23 dye. Further, the synthesized nanoflakes were utilized as an efficient electron mediator to fabricate reproducible and highly sensitive hydroquinone chemical sensor. The fabricated chemical sensor exhibited a reproducible and reliable sensitivity of 2.04 mu A mM(-1) cm(-2) and the detection limit of 2.914 mu M with the correlation coefficient (R) of 0.98815 and good linearity from 78 mu M to 12.5 mM. The observed results confirmed that the CeO2 nanoflakes can efficiently be used for photocatalytic and sensing applications. (C) 2015 Elsevier Inc. All rights reserved.