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

Abstract

The efficient electrochemical synthesis of ammonia (NH 3 ) is a topic of great concern in theoretical research and in various industries. However, given the limitations of high-performance catalysts, achieving high NH 3 yields from the electrocatalytic N 2 reduction reaction (ENRR) remains challenging. In this work, we report that a Ag-doped titanium dioxide (TiO 2 ) nanofiber catalyst synthesized by a simple electrospinning method could effectively convert N 2 into NH 3 at room temperature. The Ag-doped TiO 2 nanofibers had a high NH 3 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 TiO 2 nanofibers without obvious variations in the NH 3 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/TiO 2 nanofibers may be a highly efficient ENRR catalyst that could achieve high NH 3 yield rates. The unique structure of the interface between Ag and TiO 2 in the Ag/TiO 2 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 .

Progress of Experimental and Computational Catalyst Design for Electrochemical Nitrogen Fixation

“…∼−0.40 150 NiSb, 148 NiPc, 149 NiO@TiO 2 , 150 Ni-BCN 151 10. 75 129,162,164,165 ∼30 161 −0.05 165 ∼−0.80 166 Rh/GDY, 129 Y-TiO 2 -C, 161 BP@SnO 2−x , 162 Te-C, 163 Ag/TiO 2 , 164 SnO 2 /NC, 165 Sn/SnS 2 , 166 SnS 2 @Ni, 167 Y 1 /NC, 168 C@YSZ, 169 Te/SeO 170 Iso-eSi x , 178 F/PC, 179 Cl-GDY, 180 CNS 181 h-BNNS, 182 PNG, 183 LiN 2 /Mo, 31 LiNR, 37 Li-SICON, 38 LiCl, 39 HBTCu 40 150−200 atm are applied to ensure the favorable reaction equilibrium toward the NH 3 products. Thus, high temperature and pressure are needed to guarantee a significant turnover frequency (TOF, Figure 2B).…”