N‐Coordinated Cu–Ni Dual‐Single‐Atom Catalyst for Highly Selective Electrocatalytic Reduction of Nitrate to Ammonia

Abstract

As a traditional method of ammonia (NH3) synthesis, Haber–Bosch method expends a vast amount of energy. An alternative route for NH3 synthesis is proposed from nitrate (NO3−) via electrocatalysis. However, the structure–activity relationship remains challenging and requires in‐depth research both experimentally and theoretically. Here an N‐coordinated Cu–Ni dual‐single‐atom catalyst anchored in N‐doped carbon (Cu/Ni–NC) is reported, which has competitive activity with a maximal NH3 Faradaic efficiency of 97.28%. Detailed characterizations demonstrate that the high activity of Cu/Ni–NC mainly comes from the contribution of Cu–Ni dual active sites. That is, (1) the electron transfer (Ni → Cu) reveals the strong electron interaction of Cu–Ni dual‐single‐atom; (2) the strong hybridizations of Cu 3d—and Ni 3d—O 2p orbitals of NO3− can accelerate electron transfer from Cu–Ni dual‐site to NO3−; (3) Cu/Ni–NC can effectively decrease the rate‐limiting step barriers, suppress N–N coupling for N2O and N2 formation and hydrogen production.

Laser-controlled tandem catalytic sites of CuNi alloys with ampere-level electrocatalytic nitrate-to-ammonia reduction activities for Zn–nitrate batteries

“…Currently, the performance enhancement based on the reported catalysts of Cu–Ni tandem sites is ungratified, and the interaction of tandem sites and their behaviors in catalytic processes remains questionable. 17,18…”

“…Currently, the performance enhancement based on the reported catalysts of Cu-Ni tandem sites is ungratified, and the interaction of tandem sites and their behaviors in catalytic processes remains questionable. 17,18 In this work, as a case study of regulated tandem site catalysts, Ni was successfully introduced into the Cu foil by a facile and fast laser irradiation method, which is conducive to the formation of alloys due to the characteristics of rapid heating and cooling during the preparation. 19,20 The obtained CuNi alloy nanoparticles on the Cu foil (CuNi NPs/CF) show the ampere-level NIRR performance with the highest NH 3 production rate of 94.57 mg h À1 cm À2 , the maximum faradaic efficiency (FE) of 97.03% and good stability for 12 h in an ultrahigh-concentration NO 3 À (44.3 g L À1 ) alkaline solution.…”

Heterostructured Co/Co3O4anchored on N-doped carbon nanotubes as a highly efficient electrocatalyst for nitrate reduction to ammonia

“…44 The graphitic carbon skeleton remained stable as the D and G bands for NC substrates stayed consistent at all potentials. 45 Besides, a Raman peak at 1049 cm −1 appeared, which may be caused by the vibration modes of aqueous NO 3 − . 46 Notably, a new Raman peak centered at 1591 cm −1 could be linked to *NH 3 .…”

Rags to Riches: Meliorating the Electrocatalytic Reduction of Nitrate to Ammonia over Cu-Based Nanoalloys

“…Therefore, to tackle the particular problem of HER and enhancing the selectivity of the desired product ammonia, the catalysts should be designed meticulously . Contextually, the bimetallic nanoalloy catalysts have shown exceptional electrocatalytic performances in NO x RR, − CO 2 RR, overall water splitting, electrochemical energy storage, OER, and as a microbial fuel cell . Introduction of another metal into the Cu lattice helps in better catalytic activity apparently due to the shift in the d-band center .…”