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

Abstract

AbstractAs a traditional method of ammonia (NH3) synthesis, Haber–Bosch method expends a vast amount of energy. An alternative route for NH3synthesis 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 NH3Faradaic 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 N2formation and hydrogen production.