Preparation of nanocrystalline Cu2O by a modified solid-state reaction method and its photocatalytic activity

The nanocrystalline Cu2O was successfully prepared by calcining the precursor synthesized by a ball-milling step using Cu-2(OH)(2)CO3 and H2C2O4 center dot 2H(2)O as initial reactants without any other additives. The as-synthesized precursor and the resulting calcined product are characterized by XRD and TG/DTA. The result shows that the reaction between Cu-2(OH)(2)CO3 and H2C2O4 center dot 2H(2)O is complete after 15 min of milling and the precursors are of the crystalline sizes between 17 and 37 nm. The Cu2O is obtained with crystallite sizes of 15-21 nm after the ball-milled precursors is calcined at 310 degrees C for a certain time. The XRD also shows that the ball-milling time and the calcining time influence the crystallite sizes of the products to a certain extent. The average crystallite sizes of Cu2O decreases gradually with the increase of ball milling time, while they increase gradually with the increase of calcining time. In addition, the prepared Cu2O exhibits a high catalytic activity for the photodegradation of methyl orange under visible light irradiation, and the photocatalytic degradation ratio of methyl orange reaches to 88.7% after 2 h of irradiation. (C) 2013 Elsevier B.V. All rights reserved.