NiO nanoparticles dotted TiO 2 nanosheets assembled nanotubes P-N heterojunctions for efficient interface charge separation and photocatalytic hydrogen evolution

The low charge separation efficiency of semiconductor photocatalyst is still a stumbling block to improve photocatalytic performance. The p-n heterojunction with built-in electric field usually favors the spatial charge separation. Herein, NiO nanoparticles dotted TiO 2 nanotubes p-n heterojunction photocatalysts (NiO/TNs) are fabricated through hydrothermal and wet-impregnation strategies. The resultant NiO/TNs with relatively large surface area of 102.8 m 2 g −1 shows excellent photocatalytic H 2 production rate of 228 μmol h −1 g −1, which are four times higher than that of TNs (50 μmol h −1 g −1 ) under AM 1.5G irradiation without any cocatalyst. The high photocatalytic activity can be ascribed to the uniform growth NiO nanoparticles on surface of TNs enhancing the photoresponse to visible light region, and the formation of p-n heterojunctions induced built-in electric field promoting photogenerated electrons transmission from NiO to TNs through the heterogeneous interface, thus enhanced the charge carriers migration and separation efficiently.