Efficient photoelectrochemical water-splitting over carbon membrane linked Au and TiO₂ nanotube arrays film based on multiple carriers transport paths

Herein, a carbon membrane and Au nanoparticles were combined to improve the efficiency of photoelectrocatalytic water splitting over a TiO₂ nanotube arrays film (TiO₂ NTAF). Two different ternary nanostructures were constructed by hydrothermal and photochemical deposition processes. One was carbon membrane bridged Au nanoparticles and TiO₂ nanotube arrays (Au/C/TiO₂ NTAF), while the other was Au nanoparticles sandwiched between carbon membrane and TiO₂ nanotube arrays (C/Au/TiO₂ NTAF). The two structures exhibited enhanced visible light harvesting ability, but they showed distinctly different photoelectric properties. The unique microstructure of C/Au/TiO₂ NTAF resulted in a much higher reduction of the electron cloud density of Au nanoparticles as carrier recombination centers, which were responsible for its poor photoelectrochemical performance. However, a champion photocurrent of Au/C/TiO₂ NTAF was observed (0.984 mA cm⁻²), indicating superior ability of the photoelectrocatalytic water splitting. The great enhancement was attributed to multiple carriers transport paths, which can efficiently utilize the sensitization of the carbon membrane and the surface plasmon resonance effect of the Au nanoparticles. (paper)