Covalent Organic Framework Bifunctional Catalyst for Glucose Oxidation Reaction Coupled Nitrate to Ammonia Electrolysis

Abstract

Ammonia is a crucial feedstock for the chemical industry, a carbon-free energy source, and a safe source for hydrogen storage. The electrochemical nitrate reduction reaction (NO3RR) is one promising strategy for greener ammonia synthesis due to high water solubility and low N═O bond dissociation energy of NO3–. More importantly, polluted water is a source of NO3–. Herein, we rationally designed a bifunctional covalent organic framework catalyst (Ru-Tta-Dfp) having a triazine- and pyridine-rich backbone with inherent Ru-nanocluster sites to control both NO3– and H+ diffusion and interactions to achieve selective conversion of NO3– to ammonia monitored by operando Raman spectroscopy (93.93% faradaic efficiency and yield rate of 1.16 mg h–1cm–2 at −0.4 V vs RHE). Moreover, we have developed a strategy for the first time to couple the anodic glucose oxidation reaction (GOR) to facilitate the cathodic NO3RR with reduced energy consumption and to achieve value-added products at both electrodes. Notably, NO3RR-GOR full cell studies generate a ∼2.5 times higher NH3 yield rate than that of NO3RR-OER.