Lattice-Confined Single-Atom Fe1Sx on Mesoporous TiO2 for Boosting Ambient Electrocatalytic N2 Reduction Reaction

Mimicking natural nitrogenase to create highly efficient single-atom catalysts (SACs) for ambient N-2 fixation is highly desired, but still challenging. Herein, S-coordinated Fe SACs on mesoporous TiO2 have been constructed by a lattice-confined strategy. The extended X-ray absorption fine structure and X-ray photoelectron spectroscopy spectra demonstrate that Fe atoms are anchored in TiO2 lattice via the FeS2O2 coordination configuration. Theoretical calculations reveal that FeS2O2 sites are the active centers for electrocatalytic nitrogen reduction reaction (NRR). Moreover, the finite element analysis shows that confinement of opened and ordered mesopores can facilitate the mass transport and offer an enlarged active surface area for NRR. As a result, this catalyst delivers a favorable NH3 yield rate of 18.3 mu g h(-1) mg(cat.)(-1) with a high Faradaic efficiency of 17.3 % at -0.20 V versus a reversible hydrogen electrode. Most importantly, this lattice-confined strategy is universal and can also be applied to Ni1Sx@TiO2, Co1Sx@TiO2, Mo1Sx@TiO2, and Cu1Sx@TiO2 SACs. Our study provides new hints for the design and biomimetic synthesis of highly efficient NRR electrocatalysts.

Automated summary

In this study, S-coordinated Fe single-atom catalysts (SACs) on mesoporous TiO2 were constructed using a lattice-confined strategy for nitrogen fixation. The catalyst showed highly efficient electrocatalytic performance, and the strategy can also be applied to other metal sulfides for catalysis.