Size-Dependent Effect of Cu₂O Nanocubes in Electrochemical and Photocatalytic Properties

Abstract

Cu 2 O nanocubes with different size (ranging from 20 nm to 400 nm) were prepared by a seed-mediated method to systematically explore the strong size-dependent properties in photocatalytic degradation of methyl orange (MO). Cu 2 O nanotubes were characterized by TEM, XRD, UV-Vis measurements. The size-dependent photocatalytic efficiency of the Cu 2 O nanocubes was evaluated by degradation of methyl orange (MO) in water under visible light ( λ > 420 nm) irradiation. Furthermore, the photocurrent, linear sweep voltammetry (LSV) and electrochemical impedance spectra (EIS) measurements were applied to elucidate the size-dependent properties of Cu 2 O nanocubes, which demonstrated that smaller Cu 2 O nanocubes with certain length (30 nm) showed higher current density, faster electron transfer and lower rate of charge recombination in their exposed (100) facet. Therefore, 30 nm Cu 2 O nanocubes showed stronger visible light absorption capacity and higher photocatalytic activity in MO degradation among a series of nanocubes (20, 30, 100, 130, 200 and 400 nm) and their corresponding photocatalytic activities decreased with increasing the particles sizes.