Efficient N2 reduction with the VS2 electrocatalyst: identifying the active sites and unraveling the reaction pathway

Abstract

The electrochemical nitrogen reduction reaction (NRR) is an effective method for sustainable production of NH₃. However, a robust NRR electrocatalyst is predominantly required in order to activate the inert N₂ molecule. In this article, we report the synthesis of flower-like VS₂ (FL-VS₂) as a high-performance NRR electrocatalyst. FL-VS₂ shows the highest NH₃ yield of 34.62 μg h⁻¹ mg_cat⁻¹ with a faradaic efficiency (FE) of 2.09%, which is higher than that of the counterparts. By using first-principles calculations, we identify that the S edge site and V edge site of VS₂ easily chemisorb H⁺ and N₂, respectively. A typical poisoning experiment verifies that the V site at the edge of FL-VS₂ is the active site for the NRR. The conversion of N₂ to NH₃ is more inclined to follow a hybrid pathway at the VS₂ electrocatalyst. This research not only provides an efficient electrocatalyst for the NRR, but also offers theoretical support for identifying the active sites and reaction mechanism of the NRR on transition metal dihalide-based materials.