Enhanced Photocatalytic Activity of Cu2O/Cu Heterogeneous Nanoparticles Synthesized in Aqueous Colloidal Solutions on Degradation of Methyl Orange

Heterogeneous Cu2O/Cu nanoparticles were synthesized by a colloidal chemistry approach using ascorbic acid as a reducing agent and polyvinylpyrrolidone as a surfactant. Morphology and structure of Cu2O/Cu nanoparticles were analyzed by SEM, XRD and N2 sorption techniques. The catalytic performances of Cu2O/Cu nanoparticles for the degradation of methyl orange (MO) were investigated and reaction kinetics of MO degradation over the catalyst was also studied. The results show that the heterogeneous Cu2O/Cu nanoparticles display cobblestone-like morphology with particle sizes ranging from 20 nm to 40 nm, which are slightly smaller in particle size and higher in BET surface areas than pure Cu2O. The Cu2O/Cu nanoparticles demonstrate good potential on degradation of MO because Cu nanoparticles in the Cu2O/Cu heterostructures promote the interfacial charge-transfer kinetics between Cu and Cu2O. High initial MO concentration produces low degree of MO degradation, and increases the reaction time to reach equilibrium, and the degradation reactions follow the pseudo-first-order kinetics model. The Cu2O/Cu catalyst still exhibit good catalytic activity after 4 photodegradation cycles of MO solutions.