Fabrication, characterization and photoelectrochemical properties of cuprous oxide-reduced graphene oxide photocatalysts for hydrogen generation

Reduced graphene oxide protected Cu2O/Cu foil (rGO/Cu2O/Cu foil) photocathodes have been synthesized via a two-step strategy. (NH4)(2)S2O8 was first used to oxidize Cu foil and prepare Cu(OH)(2) nanostructures/Cu foil. In the second step, graphene oxide (GO) solution and the prepared Cu(OH)(2)/Cu foil sample were hydrothermally reacted in a Teflon lined stainless steel autoclave for different periods of time at 120 A degrees C, followed by calcination at 450 A degrees C under N-2 atmosphere for 3 h. The effect of modification of rGO on the photoelectrochemical activity of different rGO/Cu2O/Cu foil samples has been studied by FESEM, XRD, FTIR, Raman spectroscopy and UV-Vis diffuse reflectance spectroscopy. Continuous and transparent layer of GO sheets are formed on the surface of Cu(OH)(2) nanostructures/Cu foil, according to FESEM results. The photoelectrochemical properties of the prepared samples in the dark and under illumination conditions were investigated using linear sweep voltammetry and chronoamperometry techniques. The rGO/Cu2O/Cu foil photocathodes exhibit enhanced photocurrent density under illumination (85 mW/cm(2)) in comparison with the bare Cu2O/Cu foil photocathode. The improved separation efficiency of photogenerated charge carriers may be mainly accounted for this enhanced photoelectrochemical performance. A low photostability of 12.5% of the initial photocurrent density was observed for the bare Cu2O/Cu foil photocathode after 1000s of illumination whereas this value reached to almost 77% after modification of rGO. The new rGO/Cu2O/Cu foil nanocomposite prepared in this study is believed to be a promising photocathode material in photoelectrochemical cells for efficient water splitting.