Boosting the acidic electrocatalytic nitrogen reduction performance of MoS2 by strain engineering

Abstract

It has been widely confirmed that expanding the layer spacing of layer-structured MoS₂ can boost the hydrogen evolution reaction (HER) activity of MoS₂. Inspired by this, a strain engineering strategy was applied to defect-rich MoS₂ nanosheets by facilely substituting F to compress the interlayer space of MoS₂. Because of the smaller size and higher electronegativity of F as compared to S, the catalytic HER was remarkably suppressed. By considering the strongly reduced uphill energy for the hydrogenation of adsorbed N₂ on MoS₂ due to the introduction of F ions, as revealed by first-principles calculations, electrochemical nitrogen reduction reaction (NRR) activity and selectivity on the F-doped MoS₂ (F-MoS₂) catalyst under acidic conditions can be significantly boosted. Faradaic efficiency toward the NRR on F-MoS₂ was therefore enhanced to 20.6% with a maximum NH₃ yield of 35.7 μg h⁻¹ mg_cat⁻¹ at −0.2 V vs. RHE during long-term operation.