Enhanced photocatalytic hydrogen production by interface modification of 1D H2Ti3O7 structures: Effects of phase modulation and CuO co-catalyst

In the present work, the performance of TiO 2 materials featuring different one-dimensional morphologies consisting of modulated combinations of brookite, anatase, and rutile phases was evaluated in the photocatalytic production of hydrogen. These materials were synthesized by a hydrothermal method, starting from H 2 Ti 3 O 7 nanobelts. The variation of synthesis conditions of the hydrothermal method, such as HCl concentration and reaction time, enabled the modulation and formation of different proportions of brookite, anatase and rutile phases. The combination of crystalline phases enhanced the photocatalytic activity of the materials, doubling the hydrogen production (C3M-2h, 200.8 μmol) compared to the reference material (Degussa P25, 108.9 μmol). Subsequently, the synthesized materials that achieved better hydrogen production were surface modified by depositing 1 wt. % Cu through the wet impregnation method. This modification accomplished the improvement of the reaction yield by increasing the hydrogen production rate up to 146 μmol·h -1 , approximately 18 times higher than that of the base material. The characterization of the materials by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), UV-Vis spectroscopy, and Fluorescence emission spectroscopy measurements confirmed that the modulation of the crystalline phases and presence of CuO on the surface of the synthesized materials improved the mobility and separation of the ( e - -h + ) pairs, which generated less recombination and higher photocatalytic activity.