Photoelectrochemical Properties of CuCrO2: Characterization of Light Absorption and Photocatalytic H2 Production Performance

CuCrO2 delafossite was prepared by the solid-state reaction between Cr2O3 and Cu2O at high temperature (900–1100 °C). The materials were characterized by XRD, X-ray photoelectron, Raman and UV–Vis spectroscopy and transmission electron microscopy. The visible light absorption of the p-type semiconductor increased with increasing calcination temperature. First principles density functional theory calculations were used to compute the density of states and distinguish between Cr3+ d–d transitions and the charge separation electron transitions, which cannot be distinguished in CuCrO2 by UV–Vis spectroscopy. Photocathodes were prepared by depositing the as-prepared CuCrO2 on an FTO substrate by electrophoresis. The resulting cathodic photocurrents under visible light irradiation increased with increasing calcination temperature. CuCrO2 is a photostable semiconductor unlike Cu2O. Photocatalytic H2 production in ethanol/water mixtures shows that the resulting materials are active in water splitting. Co-catalysts substantially increase the activity, the most preferred one is Pt with an order of magnitude increase in performance.