Plasmonic Nickel-TiO2 Heterostructures for Visible-Light-Driven Photochemical Reactions.

Plasmon-mediated carrier transfer (PMCT) at metal-semiconductor heterojunctions has been extensively exploited to drive photochemical reactions, offering intriguing opportunities for solar photocatalysis. However, to date, most studies have been conducted using noble metals. Inexpensive materials capable of generating and transferring hot carriers for photocatalysis via PMCT have been rarely explored. Here, we demonstrate that the plasmon excitation of nickel induces the transfer of both hot electrons and holes from Ni to TiO2 in a rationally designed Ni-TiO2 heterostructure. Furthermore, it is discovered that the transferred hot electrons either occupy oxygen vacancies (VO ) or produce Ti3+ on TiO2 , while the transferred hot holes are located on surface oxygens at TiO2 . Moreover, the transferred hot electrons are identified to play a primary role in driving the degradation of methylene blue (MB). Taken together, our results validate Ni as a promising low-cost plasmonic material for prompting visible-light photochemical reactions.