Tuning the CuxO nanorod composition for efficient visible light induced photocatalysis

Abstract

A facile, low cost, and convenient method to fabricate Cu_xO (x = 1, 2) nanorod (NR) arrays is demonstrated by thermally oxidizing Cu NRs fabricated by oblique angle deposition. The single phase Cu₂O and CuO, and mixed phase Cu₂O/CuO polycrystalline NRs can be tuned simply by varying the thermal oxidation temperature. These Cu_xO NRs exhibit excellent visible light photocatalytic activity for both cationic (methylene blue) and anionic (methyl orange) dye degradations. When used as a photocathode, they also show good photoelectrochemical performance, especially the mixed phase Cu₂O/CuO NRs. The maximum stable photocurrent density is observed to be 0.24 mA cm⁻² under a simulated solar light. Incident photon-to-current efficiencies are found to be 20% and 44% at incident light wavelengths λ = 500 nm and 400 nm, respectively. These results show that the Cu_xO NRs fabricated through the oxidation method can be a suitable candidate for efficient visible light active photocatalysts for energy applications as well as for wastewater treatment.