Lattice reconstruction of one-dimensional mineral to achieve dendritic heterojunction for cost-effective nitrogen photofixation

Achieving sustainable ammonia synthesis strategies to replace traditional Haber-Bosch process remains a significant challenge; however, photo-driven catalysis system based on natural nano-minerals promises a great potential to meet the challenge. In our work, an acid-treated natural one-dimensional clay palygorskite (Pal) is substituted with iron ion to realize lattice reconstruction via a microwave-hydrothermal process. The modified Pal with Fe substitution (Fe-Pal) has the original crystal structure with a narrowed band gap. As the mass ratio of Fe is beyond 30 wt%, extra Fe2O3 precipitates on the Pal surface and the nanocomposite resembles a dendritic heterostructure, which effectively enhances visible light absorption and exposes abundant active sites for synergistic adsorption and photo-activation of nitrogen. The 60 wt% Fe-Pal nanocomposite exhibits a remarkable photocatalytic fixation capability for nitrogen under the visible light. Density function theory calculation is employed to help elucidate the photocatalytic mechanism. Our findings potentially provide a green and costeffective way to synthase nitrogen.

Automated summary

By substituting iron ions into one-dimensional clay mineral palygorskite, a narrow band gap iron-substituted nanocomposite was formed, exhibiting remarkable photocatalytic nitrogen fixation capability under visible light. Additional Fe2O3 precipitation on the surface forms dendritic heterostructure, enhancing light absorption and exposing more active sites.