Theory-guided construction of electron-deficient sites via removal of lattice oxygen for the boosted electrocatalytic synthesis of ammonia

Rational design of catalytic sites to activate the inert N equivalent to N bond is of paramount importance to advance N-2 electroreduction. Here, guided by the theoretical predictions, we construct a NiFe layered double hydroxide (NiFe-LDH) nanosheet catalyst with a high density of electron-deficient sites, which were achieved by introducing oxygen vacancies in NiFe-LDH. Density functional theory calculations indicate that the electron-deficient sites show a much lower energy barrier (0.76 eV) for the potential determining step compared with that of the pristine NiFe-LDH (2.02 eV). Benefiting from this, the NiFe-LDH with oxygen vacancies exhibits the greatly improved electrocatalytic activity, presenting a high NH3 yield rate of 19.44 mu g.h(-1).mg(cat)(-1), Faradaic efficiency of 19.41% at -0.20 V vs. reversible hydrogen electrode (RHE) in 0.1 M KOH electrolyte, as well as the outstanding stability. The present work not only provides an active electrocatalyst toward N-2 reduction but also offers a facile strategy to boost the N-2 reduction.

Automated summary

The research focuses on rational design of catalytic sites to activate the inert N equivalent to N bond, leading to the construction of a NiFe-LDH nanosheet catalyst with a high density of electron-deficient sites achieved by introducing oxygen vacancies. This catalyst exhibited greatly improved electrocatalytic activity, with a high NH3 yield rate and outstanding stability, demonstrating a facile strategy to boost the N-2 reduction process.