Electrocatalytic reduction of the pollutant nitrate to ammonia (NO3RR) using clean energy is being considered as a viable alternative to the Haber-Bosch process for producing industrially valuable ammonia. However, the multi electron-proton transfer process of the NO3RR to ammonia usually leads to poor selectivity and low current density, which still cannot meet the industrial requirements. Stabilizing the key intermediates during the reaction is particularly important for achieving high selectivity in the NO3RR towards production of NH3. Herein, we develop hydrogen bonding strategy to stabilize the key intermediates of NO3RR, which involves the design and synthesis of trinuclear copper(I) cluster-based metal organic frameworks (MOFs). The methyl groups in the copper based MOFs (DiMe-Cu3-MOF) can regulate the electron density around the Cu3 site and stabilize the key intermediates *NO2 through hydrogen bonding interaction with methyl groups. Thus, the DiMe-Cu3-MOF electrocatalyst delivers a high NH3 Faradaic efficiency (95%) of NO3RR with a high ammonia production of 401 μg•cm-2•h-1, and the partial current density of ammonia reaches an industrial level current density of -950.6 mA•cm-2. The control experiments and theoretical studies demonstrated that the introduction of methyl groups in the DiMe-Cu3-MOF can form atypical hydrogen bonding with the intermediates of the NO3RR and thus enhance the adsorption of intermediates and reduce the energy barrier of the conversion of NO3- to NH3. This work highlights the vital importance of adjusting the microenvironment through hydrogen bonding for enhancing the NO3RR performance.
