Fabrication of Fe-doped SrTiO3 photocatalyst with enhanced dinitrogen photofixation performance

摘要： 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 700oC. 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.