Visible light induced H2 evolution on the hetero-junction Pt/CuCo2O4 prepared by hydrothermal route

The photo-electrochemistry of the hetero-junction Pt/CuCo2O4 synthesized by hydrothermal route was studied to assess its ability for the H2 formation under visible light illumination. The X-ray diffraction is characteristic of mixed phases with narrow lines of the spinel CuCo2O4 and Pt. The sensitizer CuCo2O4 has a forbidden band (Eg) of 1.30 eV, well suited to the sun spectrum and displays p-type behavior. Its conduction band (−0.660 VSCE), deduced from the capacitance – potential (C−2 – E) plot, is more cathodic than the H2O/H2 level (~−0.6 VSCE), thus producing spontaneous H2 evolution under irradiation. The photoelectrons are transferred to Pt clusters, to trigger the water reduction owing to the small H2-over-potential. A quantum conversion yield of 0.65% is obtained under visible light (total flux: 15 mW cm−2, 3.42 × 1018 photons s−1) with H2 evolution rate of ~103 µmol g−1 min−1, higher than that obtained over CuCo2O4 (73 µmol g−1 min−1).