Near-Infrared Plasmon-Driven Nitrogen Photofixation Achieved by Assembling Size-Controllable Gold Nanoparticles on TiO<sub>2</sub> Nanocavity Arrays
Hao Huang, Shengyao Wang, Xingce Fan, Davin Philo, Liping Fang, Wenguang Tu, Teng Qiu, Zhigang Zou, Jinhua Ye
Abstract
Solar-driven reduction of nitrogen (N 2 ) to ammonia (NH 3 ) offers an alternative carbon-free strategy toward cleaner and more sustainable NH 3 production compared with the traditional Haber–Bosch process. However, the photofixation of N 2 by low photonic-energy near-infrared (NIR) light still represents a huge challenge. Here, we design an Au/TiO 2 hybrid plasmonic system via a solid-state dewetting process to arrange Au nanoparticles uniformly on ordered ultrathin TiO 2 nanocavity arrays based on the anodic TiO 2 templates, in which the tailored gold nanoparticle arrays serve as the mediator to guarantee NIR light harvesting and energy transfer. The oxidized layer of Ti is rich in oxygen vacancies produced simultaneously in solid-state-dewetting process which facilitates the adsorption and activation of N 2 molecules. The charge transfer and N 2 reduction reaction are driven in a tandem pathway, leading to an ammonia evaluation rate of 10.1 nmol cm –2 h –1 under NIR irradiation, while the photocatalytic performance shows no obvious decay after a cycle test. Briefly, the NIR-responsive Au/TiO 2 plasmonic photocatalyst system opens a new insight to achieve a better utilization of solar energy for photocatalytic nitrogen fixation.