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 N-2 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 N-2 into NH3 at room temperature. The Ag-doped TiO2 nanofibers had a high NH3 yield rate of 3.158 x 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 N-2 but also promotes electron exchange and the synergy between the nanofibers and N-2.