Pd1Cu Single-Atom Alloys for High-Current-Density and Durable NO-to-NH3 Electroreduction

Abstract

Electrochemical reduction of NO to NH₃ (NORR) offers a prospective method for efficient NH₃ electrosynthesis. Herein, we first design single-atom Pd-alloyed Cu (Pd₁Cu) as an efficient and robust NORR catalyst at industrial-level current densities (>0.2 A cm^-2). Operando spectroscopic characterizations and theoretical computations unveil that Pd₁ strongly electronically couples its adjacent two Cu atoms (Pd₁Cu₂) to enhance the NO activation while promoting the NO-to-NH₃ protonation energetics and suppressing the competitive hydrogen evolution. Consequently, the flow cell assembled with Pd₁Cu exhibits an unprecedented NH₃ yield rate of 1341.3 μmol h^-1 cm^-2 and NH₃-Faradaic efficiency of 85.5% at an industrial-level current density of 210.3 mA cm^-2, together with an excellent long-term durability for 200 h of electrolysis, representing one of the highest NORR performances on record.

Keywords: electrochemical reduction of NO to NH3; operando spectroscopic measurements; single-atom alloys; theoretical calculations.