Main‐Group Metal‐Nonmetal Dynamic Proton Bridges Enhance Ammonia Electrosynthesis

The electrochemical nitrogen reduction reaction (eNRR) is a crucial process for the sustainable production of ammonia (NH3) for energy and agriculture applications. However, the reaction's efficiency is highly dependent on the activation of the inert N≡N bond, which is hindered by the electron back‐donation to the π* orbitals of the N≡N bond, resulting in low eNRR capacity. Herein, we report a main‐group metal‐nonmetal (O−In−S) eNRR catalyst featuring a dynamic proton bridge, with In−S serving as the polarization pair and O functioning as the dynamic electron pool. In situ spectroscopic analysis and theoretical calculations reveal that the In−S polarization pair acts as asymmetric dual‐sites, polarizing the N≡N bond by concurrently back‐donating electrons to both the πx* and πy* orbitals of N2, thereby overcoming the significant band gap limitations, while inhibiting the competitive hydrogen evolution reaction. Meanwhile, the O dynamic electron pool acts as a “repository” for electron storage and donation to the In−S polarization pair. As a result, the O−In−S dynamic proton bridge exhibits exceptional NH3 yield rates and Faradaic efficiencies (FEs) across a wide potential window of 0.3 V, with an optimal NH3 yield rate of 80.07±4.25 μg h−1 mg−1 and an FE of 38.01±2.02 %, outperforming most previously reported catalysts. A main‐group metal‐nonmetal proton bridge catalyst (O−In−S), featuring the In−S polarization pair as asymmetric dual‐sites and electronegative oxygen as an electron pool, enables the asymmetric In−S dual‐sites to back‐donate electrons to the πx* and πy* antibonding orbitals of nitrogen (N2), achieving exceptional N2 fixation activity. This discovery paves the way for efficient electrocatalysts for activating inert molecules.