Vanadium Diboride (VB 2 ) for NO Electroreduction to NH 3 .

We report VB 2 as an efficient electrocatalyst for NO-to-NH 3 electroreduction (NORR), showing the highest NH 3 -Faradaic efficiency of 89.6% with the corresponding NH 3 yield rate of 198.3 μmol h -1 cm -2 at -0.5 V vs RHE. Theoretical calculations demonstrate that B sites of VB 2 act as the key active centers which can facilitate the NORR protonation energetics and inhibit the competitive hydrogen evolution, boosting both NORR activity and selectivity.