Oriented 2.0.0 Cu2O nanoplatelets supported on few-layers graphene as efficient visible light photocatalyst for overall water splitting

•Oriented 200 Cu2O nanoplatelets grafted on few layers graphene have been prepared by pyrolysis of Cu2+-chitosan.•Oriented 200 Cu2O grafted on graphene exhibit photocatalytic activity for overall water splitting.•A rate of 19.5 mmoles of H2 per gram of catalyst per hour has been achieved in the absence of sacrificial electron donor.•Cu2O grafted on graphene is remarkable stable upon prolonged irradiation

Cu2O nanoplatelets with preferential 2.0.0 facet orientation supported on few layers graphene were prepared as films in a single step by pyrolysis at 900 °C under inert atmosphere of Cu2+-chitosan precursor. Cu2O¯/fl-G films exhibit a photocatalytic activity for overall water splitting of 19.5 mmol/gCu+G h. This value is about 4 orders of magnitude higher than the photocatalytic activity measured for unoriented Cu2O nanoparticles on few-layers graphene or than commercial Cu2O nanoparticles and about three orders of magnitude higher than the activity reported in the literature for Cu2O nanoparticles. In addition Cu2O nanoparticles on few-layers graphene retain about 50% of its photocatalytic activity after 6 days of continuous irradiation. It is proposed that this activity and stability arises from the combination of features derived from the pyrolysis preparation procedure including strong Cu2O-graphene grafting, the role of graphene as cocatalyst and preferential 2.0.0 facet orientation.

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