The energy band structure of Cu2O, Cu2O/CuO and Cu2O/CuO/Ni.

The graphene modified Cu2O nanowire array demonstrates improved photocurrent density and photostability, attributed to the synergetic effect of graphene.

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This paper reports on the synthesis of reduced graphene oxide (RGO)-intercataled graphene oxide (GO) nano-hybrid and investigates its application in photoelectrochemical (PEC) water reduction. The optical, structural, and morphological properties of RGO-intercalated GO (RGO/GO) nano-hybrid were studied using UV-Visible spectroscopy, X-ray diffraction, and scanning electron microscopy, respectively. The reduction of GO to RGO was studied using FTIR spectroscopy. The XRD and FTIR investigation shows the strong π-π stacking interactions between the layered GO host-RGO guest sheets. An improvement in PEC water reduction activity was exhibited by RGO/GO nano-hybrid photoelectrode, with a maximum photocurrent of − 61.35 μA/cm 2 for RGO 1 wt% in GO versus − 42.80 μA/cm 2 for pristine GO photoelectrode (43% improvement). The mechanism for photocurrent enhancement was studied by electrochemical impedance analysis. The PEC performance enhancement of RGO/RO nano-hybrid photoelectrode is attributed to the strong π-π stacking interactions between RGO and GO, leading to superior electron collection and transportation by RGO and hence reduced charge carrier recombination. In addition, the UV-Visible absorption and Taut plot analysis showed the higher light harvesting efficiency of the RGO/GO compared to GO, displaying a band gap of 2.58 eV and 3.11 eV for RGO/GO and GO, respectively. The findings of this work show the potential of a strongly coupled layered host-guest nano-hybrids for high-performance optoelectronic materials. Graphic abstract