A recyclable, robust and highly active Fe2O3 nanoparticles supported over bio-silica, i.e. diatomaceous earth (Fe(2)O(3)NPs@DE) catalyzed oxidation of aryl/alkyl/heteroaryl aldehydes at room temperature has been developed. The DE enhanced the catalytic activity of Fe2O3 NPs dramatically by serving itself as a smart support. Fe(2)O(3)NPs@DE could be efficiently reused with a slight loss in its catalytic activity. The novel supported catalyst is air stable and hence all the reactions can be conducted under aerobic condition. By the measurement of the "green-ness" our protocol emerges as a benign alternative over the existing methodologies. (C) 2013 Elsevier B.V. All rights reserved.