Promoted photocatalytic N2 fixation to ammonia over floatable TiO2/Bi/Carbon cloth through relay pathway

J Colloid Interface Sci. 2024 Jun 15:664:198-209. doi: 10.1016/j.jcis.2024.02.214. Epub 2024 Mar 1.

Abstract

The floatable photocatalyst at N2-water interface allows the adequate supply of N2 reactant and the utilization of photothermal energy for photocatalytic N2 fixation, however, the presence of non-volatile NO3- product poses a challenge to the stability as it easily covers the catalytic active sites. Herein, a floatable TiO2/Bi/CC (Carbon cloth) photocatalyst was designed, in which the non-volatile NO3- can be transformed to the volatile NH3 via the newly synergistic relay photocatalysis pathway (N2 → NO3- → NH3) between TiO2 (N2 → NO3-) and Bi (NO3- → NH3). Attractively, the spontaneous NO3- → NO2- step occurs on Bi component to promote the relay pathway performing. Therefore, TiO2/Bi/CC system displays better long-term stability than TiO2/CC, and moreover, it achieves a higher NH3 yield of 8.28 mmol L-1 h-1 g-1 (i.e. 4.14 mmol h-1 m-2) than that 1.46 mmol L-1 h-1 g-1 for TiO2/Bi powder. Importantly, the N2 fixation products by TiO2/Bi/CC effectively promote lettuce growth and enhance lettuce nutrient contents, which further validates the feasibility of this system in large-scale application of crop cultivation.

Keywords: Ammonia synthesis; Crop cultivation; Floatable TiO(2)/Bi/CC; Relay pathway.