TiO2 nanotubes coupled with nano-Cu(OH)2 for highly efficient photocatalytic hydrogen production

Noble-metal-free Cu(OH)2/TNTs (TNTs: TiO2 nanotubes) nanocomposite photocatalysts were successfully prepared by loading nano-Cu(OH)2 on TNTs via a hydrothermal-precipitation process. These were then characterized in terms of morphology and physicochemical properties by employing TEM, XRD, XPS, BET, UV–Vis DRS and PL. The effects of Cu(OH)2 loading, amount of catalyst on the photocatalytic hydrogen production performance of Cu(OH)2/TNTs were investigated in detail in aqueous methanol solution under UV irradiation. The results show that, compared with pure TNTs, the TNTs loaded with highly dispersed 8 wt% Cu(OH)2 exhibited remarkably improved activity for hydrogen production (the largest quantity of evolved hydrogen was ca. 14.94 mmol h−1 g−1 catalyst) with good photostability. This high activity is attributed to the strong synergistic function of Cu(OH)2/TNTs, including suitable potential of Cu(OH)2/Cu (E0 = −0.222 V) between conduction band (−0.260 V) of TNTs and the reduction potential of H+/H2 (E0 = 0.000 V), a unique tubular microstructure of TNTs coated with nano-Cu(OH)2, large BET specific surface area and high dispersion of Cu(OH)2. Furthermore, a process mechanism for methanol/water decomposition over Cu(OH)2/TNTs is proposed to understand its high activity.

► Cu(OH)2/TNTs photocatalysts were prepared by a hydrothermal-precipitation process.
► Coupling of TNTs with nano-Cu(OH)2 greatly enhanced photocatalytic hydrogen production.
► This improved activity is due to the strong synergistic function of Cu(OH)2/TNTs.
► A possible mechanism for methanol/water decomposition over Cu(OH)2/TNTs is proposed.