Abundant Size-Controlled Cu-Ni(Fe) Alloy Nanoparticles Decorated Reduced Graphene with Enhanced Electrocatalytic Activities for Chloramphenicol

A graphene series decorated with Cu-Ni(Fe) nanoparticles (NPs) (CuxNi(Fe)(y)/G) catalysts with controlled component ratios were fabricated and applied to the electrocatalytic degradation of chloramphenicol (CAP). Cu-Ni(Fe) NPs were decorated on graphene in the sequence that the Cu was added prior to the Ni(Fe) to achieve specialized and stable structures. Cu-Ni(Fe) NPs in Cu0.5Ni0.5/G and Cu0.5Fe0.5/G had diameters of 4.29 +/- 0.03 nm and 4.63 +/- 0.04 nm, respectively. Higher peak currents (0.242 mA and 0.221 mA) for H-adsorption, a lower onset potential and higher peak current were achieved in Cu0.5Ni0.5/G (-0.045 mA at -0.136 V) and Cu0.5Fe0.5/G (-0.035 mA at -0.197 V) for the oxygen reduction reaction (ORR) than the other Cu-Ni(Fe)/G. The number of electrons transferred calculated in the ORR using Koutecky-Levich plots was 1.92, which indicated a two-electron pathway for producing H2O2. Compared with Cu-1.0/G, Ni-1.0/G and Fe-1.0/G, Cu0.5Ni(Fe)(0.5)/G had a lower onset potential, higher selectivity (%H2O2 > 80%), which could be applied to further generate HO center dot. In conclusion, attributed to the alloy effect and the stronger synergistic effect between the G and the alloy NPs, the optimal Cu0.5Ni0.5/G catalyst with smallest size of alloy NPs and the best catalytic activities exhibited the efficient properties for further degradation of CAP. (C) 2017 The Electrochemical Society. All rights reserved.