Lattice-Confined Single-Atom Fe1 Sx on Mesoporous TiO2 for Boosting Ambient Electrocatalytic N2 Reduction Reaction.

Abstract

Mimicking natural nitrogenase to create highly efficient single-atom catalysts (SACs) for ambient N2 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 FeS2 O2 coordination configuration. Theoretical calculations reveal that FeS2 O2 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 μg h-1 mgcat. -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 Ni1 Sx @TiO2 , Co1 Sx @TiO2 , Mo1 Sx @TiO2 , and Cu1 Sx @TiO2 SACs. Our study provides new hints for the design and biomimetic synthesis of highly efficient NRR electrocatalysts.