Optimization of photoelectrochemical performance in chemical bath deposited nanostructured CuO

Low cost nanostructured CuO photocathodes are fabricated via simple alkaline bath oxidation of Cu-foil at 60 degrees C in the presence of (NH4)(2)S2O8. The structural, morphological, electrical and optical properties of the as-grown CuO film are tuned by calcination in air up to 300 degrees C in order to enhance its photo-electrochemical performance. The photocathode fabricated by optimization of NaOH concentration (at 150 mM) and calcination temperature (200 degrees C), produces a photocurrent density of -1.3 mA/cm(2) at 0 V RHE under AM 1.5G simulated solar spectrum in nearly neutral pH (similar to 6.6) electrolyte. The improvement in photocurrent is attributed to enhanced photogeneration across direct band edges with a most appropriate gap of 1.55 eV instead of its inherent indirect band gap nature. The photocathode can be employed in photoelectrochemical energy conversion as well as photo-reduction of water by adopting a suitable corrosion protection scheme. (C) 2016 Elsevier B.V. All rights reserved.