ZnO nanopowderwaspreparedbyadding100mLof0.4M
NaOH solutioninto100mLof0.2MZnSO4 solution atanap-
proximaterateof10mL/minundermagneticstirring.Thenthe
mixture waskeptat60 °C for2h.ForCusource,0.005MofCuNO3
in 100mLofDIwaterhasbeenpreparedandusedasstocksolu-
tion. TheZnO:Cusamplewaspreparedbyadding50mLof
0.005MCuNO3 (taken fromtheabovestocksolution)intoZnSO4
solution aspreparedabovefollowedbyNaOHadditionandkeptat
60 °C for2h.FortheZnO:Cu:Graphenesample,50mgofGra-
phene Oxidewasdispersedin50mLofdeionizedwaterandul-
trasonicatedfor30min.100mLof0.2MZnSO4, 50mLof0.005M
CuNO3 and 4mLof0.0008MNaBH4 wereaddedslowlyintothe
beaker containingGOunderstirringfollowedbyNaOHaddition
and keptat60 °C for2h..Alltheproductswerecentrifugedand
washedbydeionizedwaterandcalcinedat400 °C for4h.