Cobalt Decoration on Cu₂O Photocatalyst via Electrodeposition for Enhanced Methylene Blue Degradation

Abstract

Cuprous oxide (Cu₂O) is a promising material for photocatalysis due to its narrow bandgap, cost-effectiveness, and non-toxicity. However, its practical application is hindered by the rapid recombination of electron-hole pairs and low stability. This study addresses these limitations by decorating Cu₂O film with a cobalt (Co) cocatalyst. The Cu₂O/Co film was successfully synthesized on indium tin oxide (ITO) substrate through electrodeposition. Characterisation results confirmed the presence of small, agglomerated Co deposits that scattered on Cu₂O grain boundaries. Electrochemical impedance spectroscopy showed that Cu₂O/Co exhibited a charge transfer resistance of 21.94 Ω, which is lower compared to Cu₂O at 24.16 Ω. This indicates that the addition of Co enhances interfacial charge transfer kinetics. Photodegradation test of Cu₂O with Co then revealed a higher degradation efficiency of 76.51% than that of Cu₂O film at 67.55%, highlighting the potential of Co as a cocatalyst for Cu₂O.