CuCo2S4 deposited on TiO2 : Controlling the pH Value Boosts Photocatalytic Hydrogen Evolution
Metallic spinel‐type CuCo2S4 nanoparticles were deposited on nanocrystalline TiO2 (P25®), forming heterostructure nanocomposites. The nanocomposites were characterized in detail by X‐ray powder diffraction (XRD), high‐resolution transmission electron microscopy (HRTEM), nitrogen sorption (BET) and UV/Vis spectroscopy. Variation of the CuCo2S4:TiO2 ratio to an optimum value generated a catalyst which shows a very high photocatalytic H2 production rate at neutral pH of 32.3 µmol/h (0.72 mL h–1), which is much larger than for pure TiO2 (traces of H2). The catalyst exhibits an extraordinary long‐term stability and after 70 h irradiation time about 2 mmol H2 were generated. An increased light absorption and an efficient charge separation for the sample with the optimal CuCo2S4:TiO2 ratio is most probably responsible for the high catalytic activity.