High Active and Selective Electrocatalytic Nitrate-to-Ammonia Conversion in Fluorine-Rich ZnF₂ Nanorod: Experimental and Theoretical Insight

Electrocatalytic reduction of nitrate (NO3–) to highest value-added ammonia (NH3) in a water system is keenly concerning at present. However, the process of NO3– to NH3 is limited by the transfer of eight electrons with various undesired byproducts and the hydrogen evolution reaction (HER). Here, the fluorine-rich ZnF2 nanorod was experimentally demonstrated and theoretically confirmed as a high active and selective catalyst for electrocatalytic NO3–-to-NH3 conversion. The introduction of fluorine can suppress the most important competition of the HER, thus achieving excellent performance. The NO3– conversion, NH3 selectivity, NH3 yield rate, and NH3 Faradaic efficiency can reach 94.93%, 96.46%, 3.901 mg h–1 mgcat.–1, and 96.92%, respectively, as well as a respectable durability. Density functional theory calculations proved that the strong adsorption of NO3– species on tetracoordinate Zn atoms can refrain the competitive HER, and the N–O bond of *ONOO would break during the first proton-coupled electron-transfer step to form *OH*ONO occupying the near catalytic site that can reduce the likelihood of nitrogen formation and improve the selectivity of NH3.