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

Abstract

Heterogeneous Cu 2 O/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 Cu 2 O/Cu nanoparticles were analyzed by SEM, XRD and N 2 sorption techniques. The catalytic performances of Cu 2 O/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 Cu 2 O/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 Cu 2 O. The Cu 2 O/Cu nanoparticles demonstrate good potential on degradation of MO because Cu nanoparticles in the Cu 2 O/Cu heterostructures promote the interfacial charge-transfer kinetics between Cu and Cu 2 O. 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 Cu 2 O/Cu catalyst still exhibit good catalytic activity after 4 photodegradation cycles of MO solutions.