Iron-doped SnS2/SnO2 heterostructures modulate interfacial electric field for efficient ammonia synthesis

Tin (Sn), owing to its unique electronic structure and inherent suppression of the hydrogen evolution reaction (HER), has garnered significant attention as an electrocatalyst for nitrogen reduction reactions (NRR). Synthesizing high-performance Sn-based heterostructure catalysts, however, remains a substantial challenge. In this study, we employ a combination of interface engineering and doping strategies to introduce iron (Fe) into the SnS 2 /SnO 2 heterostructure for the first time and develop a novel Fe-SnS 2 /SnO 2 @NF catalyst, which represents the first application of such a catalyst in NRR. Furthermore, density functional theory (DFT) calculations reveal that the introduced Fe promotes charge redistribution at the SnS 2 /SnO 2 interface, thereby enhancing the interfacial electric field. This amplified electric field plays a key role in activating orbital interactions and regulating electron distribution, thereby greatly facilitating the conversion of N 2 to NH 3 via a distal binding mechanism. This effect has been rarely reported in previous studies. Notably, the Fe-SnS 2 /SnO 2 @NF catalyst achieves an ammonia yield of 39.05 ± 2.27 μg h −1  cm −2 and a Faradaic efficiency (FE) of 29.52 ± 0.71% at room temperature, surpassing the NRR activity of other Sn-based materials. This work represents a significant advancement in understanding the role of doping strategies in enhancing the interfacial electric field of heterostructures and provides valuable insights into their effectiveness for nitrogen fixation.