Fabrication of an Fe‐Doped SrTiO3 Photocatalyst with Enhanced Dinitrogen Photofixation Performance

Abstract

SrTiO3 as semiconducting photocatalyst has been extensively investigated due to its band edges meeting the thermodynamic requirements for water splitting, but a few attention has been concentrated on its application in the NH3 synthesis via N2 photofixation process. Herein, Fe‐doped SrTiO3 (FexSr1–xTiO3) products (0 ≤ x ≤ 0.20) were synthesized via a hydrothermal process followed by calcination at 700 °C. All FexSr1–xTiO3 products (0.03 ≤ x ≤ 0.20) deliver an enhanced N2 fixation ability, and FexSr1–xTiO3 (x = 0.10) achieves the best NH3 production activity of 30.1 µmol g–1 h–1, which is 3.2‐hold higher than that of SrTiO3 alone. Once the x value is higher than 0.10, FexSr1–xTiO3 will transform into composites containing Fe‐doped SrTiO3 and α‐Fe2O3, which acts as charge recombination sites, thus causes a decreased N2 fixation activity. Further investigations demonstrate that the surface Fe3+‐doped sites can not only chemisorb and activate N2 molecules, but also promote the interfacial electron transfer from Fe‐doped SrTiO3 to N2 molecules, and thus significantly improve the N2 fixation ability. The present Fe‐doped SrTiO3 products exhibit characteristic features such as stable and efficient N2 fixation ability as well as simultaneous realization of N2 reduction and H2O oxidation without co‐catalyst, which are of significance in artificial photosynthesis with H2O as electron and proton sources.