Efficient sunlight promoted nitrogen fixation from air under room temperature and ambient pressure via Ti/Mo composites

TL;DR

This study introduces a Ti/Mo composite photocatalyst that significantly enhances nitrogen fixation from air at room temperature and ambient pressure, offering a promising sustainable approach inspired by nitrogenase activity.

Contribution

The paper presents a novel Ti/Mo composite photocatalyst with enhanced nitrogen fixation efficiency, demonstrating a 16-fold increase over pure TiO2 and providing insights into the role of surface defects and light interactions.

Findings

Nitrogen fixation performance increased 16 times compared to pure TiO2.

Nitrogen to ammonia conversion was confirmed via isotope labeling.

Maximum nitrogen fixation rate reached 432 μg·g₍cat₎⁻¹·h⁻¹.

Abstract

Photocatalytic nitrogen fixation is an important pathway for carbon neutralization and sustainable development. Inspired by nitrogenase, the participation of molybdenum can effectively activate nitrogen. A novel Ti/Mo composites photocatalyst is designed by sintering the molybdenum acetylacetonate precursor with TiO$_{2}$. The special carbon-coated hexagonal photocatalyst is obtained which photocatalytic nitrogen fixation performance is enhanced 16 times compared to pure TiO$_{2}$ at room temperature and ambient pressure. The abundant surface defects in this composite were confirmed to be the key factor for nitrogen fixation. The $^{15}$N$_{2}$ isotope labeling experiment was used to demonstrate the feasibility of nitrogen to ammonia conversion. Also, modelling on the interactions between light and the synthesized photocatalyst particle was examined for the light absorption. The optimum nitrogen fixation conditions have been examined, and the nitrogen fixation performance can reach up to 432 ${\mu}$g$\cdot$g$_{\text{cat}}^{-1}\cdot$h$^{-1}$. Numerical simulations via the field-only surface integral method were also carried out to study the interactions between light and the photocatalytic particles to further confirm that it can be a useful material for photocatalyst. This newly developed Ti/Mo composites provide a simple and effective strategy for photocatalytic nitrogen fixation from air directly under ambient conditions.