Electrochemical Reduction of N₂ into NH₃ by Donor–Acceptor Couples of Ni and Au Nanoparticles with a 67.8% Faradaic Efficiency

Abstract

The traditional NH3 production method (Haber–Bosch process) is currently complemented by electrochemical synthesis at ambient conditions, but the rather low selectivity (as indicated by the Faradaic efficiency) for the electrochemical reduction of molecular N2 into NH3 impedes the progress. Here, we present a powerful method to significantly boost the Faradaic efficiency of Au electrocatalysts to 67.8% for the nitrogen reduction reaction (NRR) by increasing their electron density through the construction of inorganic donor–acceptor couples of Ni and Au nanoparticles. The unique role of the electron-rich Au centers in facilitating the fixation and activation of N2 was also investigated via theoretical simulation methods and then confirmed by experimental results. The highly coupled Au and Ni nanoparticles supported on nitrogen-doped carbon are stable for reuse and long-term performance of the NRR, making the electrochemical process more sustainable for practical application.

Highly Efficient Photo-/Electrocatalytic Reduction of Nitrogen into Ammonia by Dual-Metal Sites

“… 25 For NRR, several heteronuclear metal-dimers anchored on N-doped graphene and phthalocyanine were proposed to have an improved catalytic activity than the corresponding homonuclear DACs. 26 , 27 Very recently, Chen et al 28 obtained a NRR Faradaic efficiency up to 67.8% by constructing donor–acceptor couples of Au and Ni nanoparticles on N-doped carbon. The donor–acceptor couples can enhance the preadsorption of N 2 and decrease the energy of desorption of NH 3 on electron-rich surface of Au simultaneously.…”

Current Progress of Electrocatalysts for Ammonia Synthesis Through Electrochemical Nitrogen Reduction Under Ambient Conditions

“…Ab imetallic electrocatalyst prepared by replacing at ransitionm etal with one of the noblem etalsa lso enhanced the NRR performance. Xue et al [64] significantly increasedt he FE of the catalyst by constructingN ia nd Au nanoparticles. Theoretical simulations provedt he presenceo fA u and Ni nanoparticles, whichp romoted the adsorption and dissociation of molecular N 2 on the active centero fe lectron-rich Figure 5.…”

Recent Advances in Electrochemical Synthesis of Ammonia through Nitrogen Reduction under Ambient Conditions

“…proposed a concept of inorganic donor‐acceptor couple Au−Ni), in which Au get electron from Ni and become electron rich, therefore, in favor of N 2 absorption and activation. This catalysts boosted the selectivity up to 67.8 % at −0.14 V vs. RHE in an acidic electrolyte . Despite that much work has been performed on the NRR, it is still far from industrial applications since the activity and selectivity of catalysts do not reach the desired level at the same time.…”