TiO2/black phosphorus heterojunction modified by Ag nanoparticles for efficient photoelectrochemical water splitting

How to improve photon absorption , photoelectric conversion efficiency, and carrier separation and transfer efficiency is a huge challenge for promoting the efficiency of photoelectrochemical (PEC) water splitting. Herein, the black phosphorus nanosheets (BPNs) was assembled on the surface of TiO 2 nanorods arrays (TiO 2 NAs) through electrostatic attraction to form TiO 2 /BP heterojunction material. Meanwhile, Ag nanoparticles were successfully loaded on the surface of TiO 2 /BP heterojunction material to form Ag nanoparticles modified TiO 2 /BP heterojunction composite material. The TiO 2 /BP heterojunction modified by Ag nanoparticles nanostructures exhibited a remarkable enhancement in the PEC water splitting in comparison with the pristine TiO 2 . Photoelectrochemical performance at 1.23 V vs. RHE bias-potential under 100 mW cm −2 solar light illumination shows that synthesized Ag–TiO 2 /BP photoanode displaying the highest photocurrent density of 1.74 mA cm −2 , which is practically 3.34 times higher than that of pristine TiO 2 (0.52 mA cm −2 ), presenting a significantly improved PEC performance for water splitting. After 18 months, the photocurrent of synthesized Ag–TiO 2 /BP photoanode can still reach 1.63 mA cm −2 , and the performance is stable. It demonstrated that the formation of heterojunction by electrostatic attraction of TiO 2 and BP and then modification with Ag nanoparticles is an effective strategy for improving the PEC water splitting.