•Double-shelled NiO/rGO/TiO2 heterostructured were successfully fabricated for the first time.•Zero-bandgap rGO can increased the barrier height by changing the Fermi level of NiO core and TiO2 shell, and enhance the strength of built-in electron field.•The design of NiO/rGO/TiO2 coaxial nanocables can ensure the efficient use of the solar lightThe construction of p–n junctions with built-in electric field effect between two photocatalytic semiconductors is an efficient strategy to separate photogenerated carriers and enhances photocatalytic activity. However the effect is limited because the built-in electric field can be saturated because of the charge accumulation during the photocatalysis process. In this work, we demonstrate that inserting a layer of zero-bandgap graphene at the interface between p-type NiO and n-type TiO2 can further enhance the separation of photogenerated carriers by building double-shelled NiO/rGO/TiO2 heterostructured coaxial nanocables This double-shell nanostructure is proved possessing a remarkably high photocatalytic activity through water splitting experiments and photoelectrochemical measurements. The main mechanism for enhancement of photocatalytic activity is that zero-bandgap rGO can increased the barrier height by lowering the Fermi level of the NiO nanofiber core and increasing the Fermi level of the TiO2 nanowire shell, and enhance the strength of built-in electron field. Furthermore, the design of NiO/rGO/TiO2 heterostructured coaxial nanocables can ensure that the UV light can be absorbed by the TiO2 at the outer shell, whereas visible light can reach the NiO inner core, thus leading to an efficient use of the white light spectrum. This heterostructured coaxial nanocable is a promising candidate for applications in environmental and energy fields because of its facile and easily scalable synthesis combined to its superior broad-spectrum photocatalytic activity.

•For the first time to utilize renewable solar and wind energy in photocatalysis for organic contaminants removal and hydrogen fuel production.•The wind driven triboelectric nanogenerator assisted photocatalysis with surprisingly high efficient.•A 3-D stereo photoelectrocatalysis system was designed: TiO2 nanowires/graphite microfiber arrays.Photoelectrocatalysis is an efficient approach for the degradation of organic pollutants as well as for water splitting. However, an external power source supplying a direct current (DC) is essential to enhance the separation of photo-induced carriers. In this paper, a fully-functional photoelectrocatalysis device was constructed by connecting single crystalline TiO2 nanowires assembled on graphite microfibers (TiO2 nanowire/graphite fiber, TNGF) to a wind-driven triboelectric nanogenerator (WDTENG). The excellent photocatalytic and photoelectrocatalytic properties of TNGF originate from the ability of graphite fibers to transport rapidly the charge carriers, the high photocatalytic activity of TiO2 nanowires and the photo-induced carrier separation enhancement created by the zero band gap of graphite. When this system is used for hydrogen generation via photoelectrocatalytic water splitting, the hydrogen evolution of the TNGF is significantly increased under assistance of the WDTENG. Photoelectrochemical analysis demonstrates that the separation and recombination of photo-induced charge carriers in the 7TNGF composite is dependent on the applied voltage bias. Thus, the wind driven generator provides large enough voltage bias for efficient charge separation, leading to a highly enhanced photocatalytic performance. This work is the first instance of high performance photoelectrocatalysis device aimed either at depollution or at hydrogen production which is entirely based on renewable energy.