CeO2-rGO Composites for Photocatalytic H2 Evolution by Glycerol Photoreforming

The interaction between CeO2-GO or CeO2-rGO and gold as co-catalysts were here investigated for solar H2 production by photoreforming of glycerol. The materials were prepared by a solar photoreduction/deposition method, where in addition to the activation of CeO2 the excited electrons were able to reduce the gold precursor to metallic gold and the GO into rGO. The presence of gold was fundamental to boost the H2 production, whereas the GO or the rGO extended the visible-light activity of cerium oxide (as confirmed by UV-DRS). Furthermore, the strong interaction between CeO2 and Au (verified by XPS and TEM) led to good stability of the CeO2-rGO-Au sample with the evolved H2 that increased during five consecutive runs of glycerol photoreforming. This catalytic behaviour was ascribed to the progressive reduction of GO into rGO, as shown by Raman measurements of the photocatalytic runs. The good charge carrier separation obtained with the CeO2-rGO-Au system allowed the simultaneous production of H2 and reduction of GO in the course of the photoreforming reaction. These peculiar features exhibited by these unconventional photocatalysts are promising to propose new solar-light-driven photocatalysts for green hydrogen production.