Cu-enhanced photoelectronic and ethanol sensing properties of Cu₂O/Cu nanocrystals prepared by one-step controllable synthesis

Metal nanocrystals are considered as effective components to enhance the photoelectronic properties of semiconductors. Herein, we report the enhancement of the photoelectronic response and photoelectronic catalysis on Cu₂O by forming a Cu nanocrystal layer on its surface via a one-step approach. The photocurrent of Cu₂O-rich Cu₂O/Cu reaches 190 μA cm^-2 in the first run and is about 4 times that of pure Cu₂O. The cyclic voltammetry (CV) signal for methanol oxidation with Cu₂O/Cu gives a higher methanol oxidation peak current than with that with Cu₂O when irradiated by ultraviolet-visible light. The ethanol gas sensing performance of Cu₂O-rich Cu₂O/Cu hetero-nanocrystals is also investigated. It is shown that the sensitivity of the Cu₂O-rich Cu₂O/Cu hetero-nanocrystals is higher (4.83) than that of Cu₂O nanocrystals (3.87) at an ethanol concentration of 2000 ppm.