Heteroatoms co-doped copper nanocrystals with negatively shifted d-band center for selective nitrate-to-ammonia production

To design high-performance electrocatalysts with desired electronic structures is critical to facilitate the conversion of pollutant nitrate (NO 3 − ) to value-added ammonia (NH 3 ) at ambient condition. Nevertheless, the current electrocatalysts for NO 3 − -to-NH 3 still face low Faradaic efficiency and selectivity. We present here a heteroatoms co-doped strategy using phosphorus (P) and oxygen (O) to tune electronic structure of copper (Cu) nanocrystals to form highly active surface for selective NO 3 − -to-NH 3 . By combing experimental results and theoretical calculation, it is found that the heteroatom P, O-doping can negatively shift the Cu d -band center, which optimizes adsorption energies of intermediates, especially for *NO 3 − and *NH 3 . The P, O-doped Cu nanocrystal exhibits an efficient 8-electron transfer process for NO 3 − -to-NH 3 . It achieves both high NO 3 − conversion rate (91.09 %) and NH 3 Faradaic efficiency (91.72 %) in high concentration NO 3 − electrolyte (1.0 M KOH + 1400 ppm NO 3 − -N), retaining its potential applications in practical NO 3 − -to-NH 3 .