Core–Shell Silicon@Mesoporous TiO2 Heterostructure: Towards Solar-Powered Photoelectrochemical Conversion

Graphical Powered by the sun : A facile and low-cost synthesis of core–shell p-Si@mesoporous n-TiO 2 hybrid material was developed for solar-driven photoelectrochemical (PEC) production of H 2 . Core–shell heterostructured nanomaterials with mesopores have enormous potential applications in diverse fields. Herein, we report a facile extended Stöber method to synthesize core–shell heterostructured semiconducting nanomaterials with mesoporosity. Silver (Ag) metal-assisted chemically wet etched p-type silicon nanowires (Si NWs) were used as the core, and layer-controllable mesoporous n-type anatase TiO 2 was grown as the shell to successfully fabricate the core–shell p-Si@mesoporous n-TiO 2 hybrid materials. Detailed characterization reveals that the TiO 2 shell was composed of aggregated crystalline TiO 2 nanoparticles with diameters of ≈15 nm, where the TiO 2 coating thickness was tuned ≈50 nm. The interstitial pores of these nanoparticles were observed with average pore sizes of 4–8 nm. The core–shell structured p-Si@mesoporous n-TiO 2 hybrid materials were demonstrated as photocathodes for the solar-driven photoelectrochemical (PEC) production of H 2 at the semiconductor/electrolyte interface.