Electrochemical Reduction of N2 into NH3 under Ambient Conditions Using Ag-doped TiO2 Nanofibers

The efficient electrochemical synthesis of ammonia (NH3) is a topic of great concern in theoretical research and in various industries. However, given the limitations of high-performance catalysts, achieving high NH3 yields from the electrocatalytic N2 reduction reaction (ENRR) remains challenging. In this work, we report that a Ag-doped titanium dioxide (TiO2) nanofiber catalyst synthesized by a simple electrospinning method could effectively convert N2 into NH3 at room temperature. The Ag-doped TiO2 nanofibers had a high NH3 yield rate of 3.158 × 10–10 mol s–1 cm–2 with a Faradaic efficiency (FE) of 0.13% at a low overpotential of −0.6 V versus a reversible hydrogen electrode (RHE) in acidic solution (0.1 mol L–1 HCl). The absence of hydrazine in the system proved that the prepared catalyst has excellent selectivity. Operation for eight consecutive cycles at an overpotential of −0.6 V vs RHE demonstrated the high stability of the Ag-doped TiO2 nanofibers without obvious variations in the NH3 yield rate and FE. The current density in the chronoamperometric curve did not decrease remarkably over 12 h of continuous electrolysis, thus confirming the durability of the catalyst. This work proves that Ag/TiO2 nanofibers may be a highly efficient ENRR catalyst that could achieve high NH3 yield rates. The unique structure of the interface between Ag and TiO2 in the Ag/TiO2 nanofibers prepared by electrospinning not only enhances the adsorption of N2 but also promotes electron exchange and the synergy between the nanofibers and N2.