Boosting Electrocatalytic Ammonia Production through Mimicking “π Back-Donation”

Electrocatalytic dinitrogen reduction reaction (N₂RR) is an emerging route for ammonia synthesis at ambient conditions. Albeit the “π back-donation” process enables N₂RR activity on transition metals with empty d-orbitals, given its dilemma in overcoming hydrogen evolution reaction (HER) competition, exploring p-block-element-based catalysts with relatively inferior HER activity is achievable for high selectivity. The challenge lies in designing rational structure to improve N₂RR activity. Here, we synergistically integrate oxygen vacancy (V_O) with hydroxyl on Bi₄O₅I₂ (V_O-Bi₄O₅I₂-OH), which render this p-block-element-based material active to mimic “π back-donation” behavior because of sufficient vacant orbitals. In neutral media, the electrocatalytic N₂RR performance of V_O-Bi₄O₅I₂-OH in terms of splendid faradic efficiency (32.4%) is superior to most of the prior reports using p-block-element-based catalysts. Our findings show a new strategy toward standout N₂RR activity, which holds great potential in exploiting other p-block-element-based electrocatalysts.