Construction of solid-state Z-scheme carbon-modified TiO2/WO3 nanofibers with enhanced photocatalytic hydrogen production

Carbon-layer-coated TiO 2 /WO 3 nanofibers (WTC) were fabricated by combining the electrospinning technique (for TiO 2 /WO 3 nanofibers) and hydrothermal method (for carbon shell). The structure characterization results showed that TiO 2 /WO 3 nanofibers (WT) were encased within an uniform carbon shell about 10 nm in thickness. By adjusting the content of WO 3 , the graphitization degree of carbon layer could be controlled, and the WTC nanofibers had remarkable light absorption in the visible region. Furthermore, the photoelectrochemical performance and photocatalytic activity were investigated systematically. As expected, the H 2 -generation rate of the as-prepared composite materials was greatly enhanced compared with pure TiO 2 nanofibers (TNFs), TiO 2 /WO 3 nanofibers (WT) and TiO 2 @carbon core/shell nanofibers (TC). The enhanced activities were mainly attributed to the multichannel-improved charge-carrier photosynthetic heterojunction system with the carbon layer on the surface of TiO 2 as an electron collector and WO 3 as a hole collector, leading to effective charge separation on these components, which were evidenced by photoluminescence spectroscopy (PL), electrochemical impedance spectroscopy (EIS) and photocurrent analysis. Besides, the addition of WO 3 promoted the graphitization of carbon layer, which in turn improved transport of electrons in the carbon layer and also contributed to the performance improvement.